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When woven together, the tapestry of experiences of staff and scientists provide the complete picture of OCO-2.<\/strong><\/p>\nBreathe in\u2026 Breathe out.<\/strong><\/em><\/p>\nThis simple rhythm sets the foundation of life on Earth \u2013 and it\u2019s a pattern that a NASA satellite has been watching from space for over a decade.<\/p>\nOn July 2, 2024, NASA\u2019s Orbiting Carbon Observatory-2 (OCO-2) celebrated 10 years since its launch. Built by NASA\/Jet Propulsion Laboratory (NASA\/JPL), OCO-2 is now viewed as the gold standard for carbon dioxide (CO2<\/sub>) measurements from space and has quietly become a powerful driver of technological, ecological and even economic progress \u2013 including providing unexpected insights into plant health, crop-yield forecasting, drought early warning systems, and forest and rangeland management.\u00a0<\/p>\nWhile the mission can point to many scientific achievements \u2013 some of which will be highlighted in the pages that follow \u2013 these accomplishments have occurred in the context of a larger human story. Scientists from around the world have come together to bring the important data from this satellite to the broader community, making OCO-2 the success that it is today.<\/p>\nThis article provides readers an introduction to several transformative characters in this carbon story. The text peers behind the scenes to reveal the circuitous path that scientists and engineers must navigate to take a brilliant scientific concept and turn it into flight hardware that can be launched into space to make beneficial observations. The article depicts milestones that mark the mission\u2019s successes, but also the failures, dead ends, long nights, and discouragements that make up the complexity of any science story.<\/p>\n2003<\/em><\/strong>: The First OCO Science Team Meeting<\/strong><\/p>\nMeasuring CO2<\/sub> from space: Great idea but can it really be done?<\/strong><\/em><\/p>\nWhen the idea for OCO was first proposed, it wasn\u2019t universally embraced. At the time, more than a few experts scoffed at the idea that CO2<\/sub> could be measured from space. Unlike nitrogen and oxygen, which are the dominant components of Earth\u2019s atmosphere, CO2<\/sub> is a trace gas, often no more than a few hundred parts per million. Miniscule, elusive, and nomadic, these measurements, though challenging, are crucial because of the important role CO2<\/sub> plays in global climate.<\/p>\nIn April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Breathe in\u2026 Breathe out.<\/strong><\/em><\/p>\nThis simple rhythm sets the foundation of life on Earth \u2013 and it\u2019s a pattern that a NASA satellite has been watching from space for over a decade.<\/p>\nOn July 2, 2024, NASA\u2019s Orbiting Carbon Observatory-2 (OCO-2) celebrated 10 years since its launch. Built by NASA\/Jet Propulsion Laboratory (NASA\/JPL), OCO-2 is now viewed as the gold standard for carbon dioxide (CO2<\/sub>) measurements from space and has quietly become a powerful driver of technological, ecological and even economic progress \u2013 including providing unexpected insights into plant health, crop-yield forecasting, drought early warning systems, and forest and rangeland management.\u00a0<\/p>\nWhile the mission can point to many scientific achievements \u2013 some of which will be highlighted in the pages that follow \u2013 these accomplishments have occurred in the context of a larger human story. Scientists from around the world have come together to bring the important data from this satellite to the broader community, making OCO-2 the success that it is today.<\/p>\nThis article provides readers an introduction to several transformative characters in this carbon story. The text peers behind the scenes to reveal the circuitous path that scientists and engineers must navigate to take a brilliant scientific concept and turn it into flight hardware that can be launched into space to make beneficial observations. The article depicts milestones that mark the mission\u2019s successes, but also the failures, dead ends, long nights, and discouragements that make up the complexity of any science story.<\/p>\n2003<\/em><\/strong>: The First OCO Science Team Meeting<\/strong><\/p>\nMeasuring CO2<\/sub> from space: Great idea but can it really be done?<\/strong><\/em><\/p>\nWhen the idea for OCO was first proposed, it wasn\u2019t universally embraced. At the time, more than a few experts scoffed at the idea that CO2<\/sub> could be measured from space. Unlike nitrogen and oxygen, which are the dominant components of Earth\u2019s atmosphere, CO2<\/sub> is a trace gas, often no more than a few hundred parts per million. Miniscule, elusive, and nomadic, these measurements, though challenging, are crucial because of the important role CO2<\/sub> plays in global climate.<\/p>\nIn April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
This simple rhythm sets the foundation of life on Earth \u2013 and it\u2019s a pattern that a NASA satellite has been watching from space for over a decade.<\/p>\n
On July 2, 2024, NASA\u2019s Orbiting Carbon Observatory-2 (OCO-2) celebrated 10 years since its launch. Built by NASA\/Jet Propulsion Laboratory (NASA\/JPL), OCO-2 is now viewed as the gold standard for carbon dioxide (CO2<\/sub>) measurements from space and has quietly become a powerful driver of technological, ecological and even economic progress \u2013 including providing unexpected insights into plant health, crop-yield forecasting, drought early warning systems, and forest and rangeland management.\u00a0<\/p>\nWhile the mission can point to many scientific achievements \u2013 some of which will be highlighted in the pages that follow \u2013 these accomplishments have occurred in the context of a larger human story. Scientists from around the world have come together to bring the important data from this satellite to the broader community, making OCO-2 the success that it is today.<\/p>\nThis article provides readers an introduction to several transformative characters in this carbon story. The text peers behind the scenes to reveal the circuitous path that scientists and engineers must navigate to take a brilliant scientific concept and turn it into flight hardware that can be launched into space to make beneficial observations. The article depicts milestones that mark the mission\u2019s successes, but also the failures, dead ends, long nights, and discouragements that make up the complexity of any science story.<\/p>\n2003<\/em><\/strong>: The First OCO Science Team Meeting<\/strong><\/p>\nMeasuring CO2<\/sub> from space: Great idea but can it really be done?<\/strong><\/em><\/p>\nWhen the idea for OCO was first proposed, it wasn\u2019t universally embraced. At the time, more than a few experts scoffed at the idea that CO2<\/sub> could be measured from space. Unlike nitrogen and oxygen, which are the dominant components of Earth\u2019s atmosphere, CO2<\/sub> is a trace gas, often no more than a few hundred parts per million. Miniscule, elusive, and nomadic, these measurements, though challenging, are crucial because of the important role CO2<\/sub> plays in global climate.<\/p>\nIn April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
While the mission can point to many scientific achievements \u2013 some of which will be highlighted in the pages that follow \u2013 these accomplishments have occurred in the context of a larger human story. Scientists from around the world have come together to bring the important data from this satellite to the broader community, making OCO-2 the success that it is today.<\/p>\n
This article provides readers an introduction to several transformative characters in this carbon story. The text peers behind the scenes to reveal the circuitous path that scientists and engineers must navigate to take a brilliant scientific concept and turn it into flight hardware that can be launched into space to make beneficial observations. The article depicts milestones that mark the mission\u2019s successes, but also the failures, dead ends, long nights, and discouragements that make up the complexity of any science story.<\/p>\n
2003<\/em><\/strong>: The First OCO Science Team Meeting<\/strong><\/p>\nMeasuring CO2<\/sub> from space: Great idea but can it really be done?<\/strong><\/em><\/p>\nWhen the idea for OCO was first proposed, it wasn\u2019t universally embraced. At the time, more than a few experts scoffed at the idea that CO2<\/sub> could be measured from space. Unlike nitrogen and oxygen, which are the dominant components of Earth\u2019s atmosphere, CO2<\/sub> is a trace gas, often no more than a few hundred parts per million. Miniscule, elusive, and nomadic, these measurements, though challenging, are crucial because of the important role CO2<\/sub> plays in global climate.<\/p>\nIn April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Measuring CO2<\/sub> from space: Great idea but can it really be done?<\/strong><\/em><\/p>\nWhen the idea for OCO was first proposed, it wasn\u2019t universally embraced. At the time, more than a few experts scoffed at the idea that CO2<\/sub> could be measured from space. Unlike nitrogen and oxygen, which are the dominant components of Earth\u2019s atmosphere, CO2<\/sub> is a trace gas, often no more than a few hundred parts per million. Miniscule, elusive, and nomadic, these measurements, though challenging, are crucial because of the important role CO2<\/sub> plays in global climate.<\/p>\nIn April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
When the idea for OCO was first proposed, it wasn\u2019t universally embraced. At the time, more than a few experts scoffed at the idea that CO2<\/sub> could be measured from space. Unlike nitrogen and oxygen, which are the dominant components of Earth\u2019s atmosphere, CO2<\/sub> is a trace gas, often no more than a few hundred parts per million. Miniscule, elusive, and nomadic, these measurements, though challenging, are crucial because of the important role CO2<\/sub> plays in global climate.<\/p>\nIn April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
In April 2003, a handful of hopeful scientists gathered at the California Institute for Technology (Caltech) for the first OCO Science Team meeting. To mark the occasion, they took a break during the meetings and lined up for a group photo \u2013 see Photo 1<\/strong>. Upon returning to work, they took up the arduous task of determining how to measure CO2<\/sub> from space with a satellite and instrument hardware that simply did not exist.<\/p>\nOCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
OCO-2 was developed as part of NASA\u2019s Earth System Science Pathfinder <\/a>program, which supports small, low-cost missions that can still provide tremendous value for high-impact goals. The satellite carries a high-resolution spectrometer that collects data in three, narrow spectral bands. These spectral bands follow a divide and conquer strategy \u2013 two measure the clear \u201cfingerprint\u201d that CO2<\/sub> leaves when it absorbs sunlight, and one takes the same measurement for oxygen (O2<\/sub>). The satellite is able to estimate CO2<\/sub> concentrations by comparing the CO2<\/sub> and O2<\/sub> measurements.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 1<\/strong>. A photo of participants during the original OCO Science Team meeting in 2003 at the California Institute of Technology. <\/div>\nPhoto credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
2014: A Night at Vandenberg Air Force Base \u2013 To Launch or Not to Launch<\/strong><\/p>\nA Mother and daughter await the midnight launch.<\/em><\/strong><\/h4>\nOn a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
On a warm July evening in 2014, Vivienne Payne<\/strong> [JPL\u2014current OCO-2 Project Scientist<\/em>] would normally have tucked her four-year-old daughter into bed. But this night was special. They were lined up in a crowd waiting for a bus to take them to Vandenberg Air Force Base (now Space Force Base) in California. The group huddled in the chill night air awaiting the launch of the OCO satellite into the cosmos.<\/p>\nShortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\nWhile Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Shortly after midnight, hundreds of guests spread blankets across the gravelly ground to make their wait more comfortable. The air was charged with excitement. The participants waited quietly, murmuring to one another while the soft slosh of the Pacific Ocean offered a steady pendulum counting down to the impending launch. Like most people there that night, Vivienne felt upbeat and excited, but she also understood the gravity of the moment \u2013 a lot was riding on this launch.<\/p>\n
While Vivienne had not been part of OCO since inception \u2013 having joined the project in 2012 \u2013 she knew OCO\u2019s story.\u00a0The first launch in 2009 ended in failure \u2013 when a faulty launch vehicle doomed the first OCO to a watery grave just moments after launch. In the aftermath, the OCO community were left in limbo, unsure if the project would survive. All was not lost. The Japan Aerospace Exploration Agency (JAXA) had successfully launched the Greenhouse-gas Observing satellite<\/a> (GOSAT or IBUKI<\/em>, Japanese for \u201cbreath\u201d) that same year. This launch gave the OCO team an opportunity to test and refine their methods and algorithms using data from GOSAT.<\/p>\nAs the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\nVivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\nFortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\nFor Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\nAs they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
As the gravel poked through the thick flannel blankets, Vivienne shifted uncomfortably waiting for the interminable countdown to reach its conclusion \u2013 and then everything stopped. A technical issue was detected, triggering a command to abort the launch.<\/p>\n
Vivienne tried to explain to her disappointed daughter that this was simply how things went with space work. Sometimes you put in 1000 work-years of labor, get up in the middle of the night, and sit on uneven ground just to have everything stopped, unceremoniously.<\/p>\n
Fortunately, the problem was quickly resolved, and the launch was rescheduled for the very next night. The participants returned to the staging site \u2013 rinse and repeat. This time Vivienne\u2019s daughter was decidedly more sluggish. At 3:00 AM PDT, OCO-2 launched flawlessly into space. Unfortunately, a layer of fog obscured the spectators\u2019 view. While it could not be seen, the resounding boom of the rocket taking off could be heard for miles.<\/p>\n
For Vivienne, the sonic boom shocked the ears and rumbled through the bodies of the assembled crowd, who erupted in cheers. Having invested a lot of her time in the OCO project during the past two years, she was thrilled to see a successful launch. <\/p>\n
As they returned to their hotel, Vivienne\u2019s daughter remained unimpressed. \u201cMummy, let\u2019s not do that again,\u201d she said as she splayed out on the hotel bed and soon fell fast asleep.<\/p>\n
2014: OCO-2 Joins A Larger Earth Observing Story<\/strong><\/p>\nLeading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Leading to surprising new insights about how we see plants \u2013 and fires<\/strong><\/em>.<\/p>\nWhen OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
When OCO-2 launched in 2014, it joined a tightly coordinated group of Earth-observing satellites known as the Afternoon Constellation <\/a>(or the \u201cA-Train\u201d) \u2013 see Figure 1<\/strong>. Flying in formation, the satellites could combine their observations to unlock more than any one mission could reveal on its own. Around the same time, scientists discovered that OCO-2 could do more than measure CO2<\/sub> \u2013 it could also detect signs of plant health.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 1<\/strong>. As of January 2024, the international Afternoon Constellation (\u201cA-Train\u201d) has two missions remaining: OCO-2 and GCOM-W. While Aqua and Aura continue to collect science data, the satellites have both slowly drifted out of the constellation \u2013 and will soon be decommissioned. CALIPSO ended its scientific mission on August 1, 2023. CloudSat radar operations ceased on December 20, 2023.<\/div>\nFigure credit<\/strong>: NASA<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nThis discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
This discovery opened the possibilities for many different people, including Madeleine Festin<\/strong>, a former wildland firefighter in Montana, to work with OCO-2 data through an internship sponsored by the DEVELOP<\/a> program, under the Earth Action<\/a> element (formerly known as Applied Sciences<\/a>) of NASA\u2019s Earth Science Division.<\/p>\nWhen she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\nOCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
When she was on the ground battling fires, Madeleine faced the harsh reality that fire prediction is notoriously difficult. In the field, she might be surrounded by smoke with just 20 ft (6 m) of visibility and red flames tearing through dry brush. Through her internship, she\u2019s continued to tackle fires \u2013 just from a very different vantage point.<\/p>\n
OCO-2 can detect the faint glow given off by plants during photosynthesis. This glow, called solar-induced fluorescence<\/em> (SIF), offers a fast, sensitive indicator of plant health \u2013 see Figure 2<\/strong>. While other satellite-based tools, such as soil moisture or vegetation indices often detect stress only after damage has already occurred, SIF values drop the moment photosynthesis slows down \u2013 even if the plant still looks green. These data open the door to new applications: monitoring crop performance, identifying flood-damaged areas, and tracking drought before it sparks wildfires. That\u2019s exactly how Madeleine is now using the data.<\/p>\nMadeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\nWhat makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Madeleine\u2019s team, a collaboration between OCO-2 scientists and the U.S. Forest Service, is working to update fire-risk models \u2013 some of which were developed in the 1980s \u2013 by incorporating SIF data.<\/p>\n
\u201cIt\u2019s fulfilling to know that you\u2019re helping people,\u201d Madeleine says. \u201cAnd it\u2019s nice to see science and firefighting work align.\u201d<\/p>\n
What makes the data even more powerful is OCO-2\u2019s synergy with its A-Train counterpart, the Moderate Resolution Imaging Spectroradiometer<\/a> (MODIS) instrument on NASA\u2019S Aqua<\/a> platform. MODIS contributes land-cover information that, when paired with OCO-2\u2019s SIF measurements, creates a detailed, global dataset of plant photosynthesis far beyond what either satellite could produce on its own. This example is a perfect synergistic pairing of measurements the A-Train has made possible. This information gives Madeleine and her team a better foundation for improving fire prediction tools.<\/p>\n\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n\n\n\n<\/a><\/figure>\nFigure 2<\/strong>. OCO-2 can measure plant health and photosynthesis from space. Puente Hills in eastern Los Angeles County, CA was once one of the largest landfills in the United States. The landfill has since been closed and its surface replanted to resemble a natural hill rising above the surrounding densely populated neighborhoods. These two images show how solar induced fluorescence<\/em> (SIF), or \u201cplant glow,\u201d measured from OCO-2 and OCO-3 can be used to study urban greenery. The satellite image of the landfill and surrounding area [left<\/em>] is followed by the SIF data overlay [right<\/em>]. It is possible to compare the photosynthetic activity in the reclaimed landfill to nearby green spaces, as well as the plant health in the surrounding neighborhoods.<\/div>\nFigure credit<\/strong>: NASA\/Jet Propulsion Laboratory OCO-2, OCO-3<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
\u201cWhen firefighting, I used to hear about all these fire indices and metrics, and never knew what they meant,\u201d Madeleine says. \u201cNow, I\u2019m learning the science behind it. And it\u2019s interesting to think about how to get that information to firefighters on the ground, without overburdening them. What do they really need to know, and how can we deliver it in a way that helps?\u201d<\/p>\n
2016: Trekking to the Desert to Calibrate OCO-2<\/strong><\/p>\nA technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
A technologist tramps around in the desert for instrument calibration.<\/strong><\/em><\/p>\nCarol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>] had been to the Nevada desert so many times that she knew the way by heart. After skirting the Sequoia Forest and stopping for the night just past the Nevada border, she led a caravan of scientists along Highway 6 to mile marker 100, turning right onto a dirt road between two fence posts. Traveling 10 mi (16.5 km) down the road, a cloud of dust raised up from the car tires before the vehicle came to a stop at their destination \u2013 a patch of spindly instruments hammered into the barren desert floor. A big plaque marked the spot with the NASA logo and the words, \u201cSatellite Test Site.\u201d Standing under vast blue sky, Carol felt like she\u2019d come home. Over the past few years, Carol had grown accustomed to leading these summer expeditions to Railroad Valley, NV. Often the team from JPL is joined by guests from Japan and other international colleagues representing various satellite missions \u2013 see Photo 2<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 2<\/strong>. Group photo at Railroad Valley, NV during a summer field campaign. Carol Bruegge<\/strong> [OCO-2\u2014Technologist<\/em>, fifth from left<\/em>] joins JPL members and guests from Japan working on the Greenhouse-gas Observing satellite. The group included [left to right<\/em>] Hirokazu Yamamoto, Atsushi Yasuda, Hideaki Nakajima, Kei Shiomi, Thomas Pongetti, Bruegge, Dejian Fu, Junko Fukuchi, Makoto Saito, and Rio Kajiura.<\/div>\nPhoto credit<\/strong>: Tom Pongetti<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nCarol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Carol knew that a successful field campaign required that they protect the instruments from the thick corrosive salt on the ground. Then the work could begin. The team hiked through the desert, collecting data that would ensure that OCO-2 could continue to provide high-quality data. As they hiked, the team carried hand-held spectrometers and measured the reflection of sunlight off Earth\u2019s surface \u2013 timed precisely to match the moment the satellite passes overhead. By comparing the satellite\u2019s readings with the ground-based measurements, the team can check the accuracy of the satellite readings. Reflection is one ingredient used in calculating the concentration of CO2<\/sub> in the overlying air.<\/p>\nThis remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
This remote location in Nevada wasn\u2019t chosen by accident. In this part of the desert, the ground is perfectly flat, free of plants, and surrounded by ground littered with salt. This smooth, bare surface means no bumps and textures could disrupt the signal. For satellite calibration, it doesn\u2019t get better than this.<\/p>\n
2018: A Contentious Meeting in Noordwijk, Netherlands Sparks A Revolution<\/strong><\/p>\nCould OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Could OCO-2 data be used to construct a nation-by-nation CO2<\/sub> budget?<\/strong><\/em><\/p>\nDavid Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
David Crisp<\/strong> [JPL emeritus<\/em>\u2014original OCO Principal Investigator and former<\/em> OCO Science Team Leader<\/em>] was tired. He didn\u2019t know if it was jet lag or a reflection of the 16- to 18-hour workdays that had persisted for weeks. This particular week had started with a 10-hour flight from Los Angeles to the Netherlands. Now, he was standing in front of carbon scientists who had gathered from around the world.<\/p>\n\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
\u201cWe need to put together a team that will be brave enough to make a CO2<\/sub> budget, nation-by-nation,\u201d David said.<\/p>\nHis statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\nDespite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
His statement was met with thoughtful silence. Neither the data nor the models were ready. The consensus in the room was that the proposed venture may not work. David was magnanimous toward his critics, but he persisted with his idea.<\/p>\n
Despite the rocky start, David met with representatives in charge of creating national emission inventories. He could see exasperation on their faces \u2013 running ragged, short-staffed, and trying to tally up every single barrel of oil and bushel of coal burned within their country\u2019s boundaries. Even more challenging was tallying other tasks, such as deforestation and agricultural practices. David firmly believed that if OCO-2 could provide independent estimates from space as promised, it would provide the on-the-ground \u201ccarbon accountants\u201d a reliable comparison \u2013 see Figure 3<\/strong>.<\/p>\n\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\nAlthough David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
\u201cWe might have a satellite that can help,\u201d Dave told them.<\/p>\n
Although David has since retired, his perseverance is now bearing fruit. What began as a hypothetical solution is now much closer to reality. OCO-2\u2019s high-precision measurements can now detect CO2<\/sub> linked not just to countries, but large cities, industrial zones, and even individual power plants \u2013 all while researchers continue perfecting efforts to identify contributions from specific city sectors. OCO-2 provides a valuable, independent reference that nations can use to track the progress of their emission inventories. Researchers have created an entire OCO-2-sourced database of CO2<\/sub> estimates by country, available through the U.S. Greenhouse Gas Center<\/a>.<\/p>\n\n\n\n<\/a><\/figure>\nFigure 3<\/strong>. A map of the net emissions and removals of carbon dioxide (CO2<\/sub>) for 2015\u20132020 using estimates informed by OCO-2. Green depressions represent countries that remove more CO2 <\/sub>than emitted. Tan or red ridges represent countries with higher CO2<\/sub> emissions than removed.<\/div>\nFigure credit<\/strong>: NASA Science Data Visualization Studio<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\n2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
2019: Another OCO Takes flight \u2013 This Time to The International Space Station <\/strong><\/p>\nUsing \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Using \u201cspare parts\u201d to get more details about plant health and the carbon cycle.<\/strong><\/em><\/p>\nAfter completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
After completing OCO-2, enough spare parts remained to construct a sister mission \u2014 OCO-3, which launched in 2019 to continue the work of measuring CO2<\/sub> in the atmosphere from the International Space Station (ISS). The satellite\u2019s unique orbit gives it a new vantage point. While OCO-2 continues to orbit Earth in a near-polar path, OCO-3 travels aboard the ISS in a lower, shifting orbit that allows it to study different areas of Earth\u2019s surface at different times of day. OCO-3 also features a special scanning mode, called the snapshot area mapping<\/em> (SAM) that lets scientists zoom in on areas of interest (e.g., cities or volcanoes) to study carbon emissions and vegetation in greater detail. Together, OCO-2 and OCO-3 provide complementary perspectives on Earth\u2019s carbon cycle and plant health at space and time resolutions that have not been possible from space before.<\/p>\n2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
2021: LA During a Pandemic Is a Far Cry from Finland<\/strong><\/p>\nA data scientist foregoes saunas and berry-picking to make the dream of OCO-2 a reality.<\/strong><\/em><\/h4>\nOtto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Otto Lamminp\u00e4\u00e4<\/strong> [JPL\u2014Data Scientist<\/em>] opened the picture his sister had texted him. His family looked back with wide smiles, holding buckets overflowing with scarlet berries and framed by the velvety firs of Finland. It had been almost two years since he\u2019d seen them in person. He\u2019d moved to Los Angeles to work at JPL on the OCO-2 and OCO-3 mission just as the COVID-19 pandemic engulfed the planet \u2013 see Photo 3<\/strong>.<\/p>\n\n\n\n<\/a><\/figure>\nPhoto 3<\/strong>. Otto Lamminp\u00e4\u00e4<\/strong> and Amy Braveman<\/strong> [both from JPL] in Finland.<\/div>\nPhoto credit<\/strong>: Otto Lamminp\u00e4\u00e4<\/div>\n<\/figcaption><\/div>\n<\/div>\n<\/div>\nOtto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
Otto had never gone a week without seeing his family or skipped a berry-hunting party in the forests of his native Finland. With the forced distance, he placed himself in his home forests in his mind. He used this memory to marvel at the capacity of the vast forests to \u201cbreathe in\u201d CO2<\/sub>\u00a0and convert it into trunks, branches, and roots through photosynthesis. With the COVID-19-imposed travel restrictions, Otto wasn\u2019t sure how long he\u2019d have to wait to go back home. <\/p>\nBut whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n
But whenever that homecoming occurred, Otto knew that a piece of OCO-2 would be waiting for him. North of the Arctic Circle in Sodankyl\u00e4, a cluster of Earth instruments nestled in a snowy meadow include a field station that is part of the\u00a0Total Carbon Column Observing Network<\/a> (TCCON) of Fourier Transform Spectrometers (FTS). These stations act as OCO-2 and OCO-3\u2019s \u201cground crew.\u201d As the satellites orbit Earth, the FTS simultaneously measures direct solar spectra in the near-infrared spectral region, which allows for retrieval of column-averaged CO2<\/sub> concentrations, as well as other key atmospheric constituents, over the snowy meadow. Back in the lab, Otto, along with other OCO-2 and OCO-3 scientists, compare the data collected at the field station to the satellite data. This feature was detailed in The Earth Observer<\/em>\u00a0article, titled \u201cIntegrating Carbon from the Ground Up: TCCON Turns Ten,\u201d was published July\u2013August 2014, Volume 26 issue 4, pp. 13\u201317).<\/a><\/p>\n\n\n\n<\/a><\/figure>\nFigure 4<\/strong>. Global map of the ground stations, also known as the Total Carbon Column Observing Network (TCCON). The red dots mark the active ground observation stations to validate OCO-2 and OCO-3 data.<\/div>\n