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Preparations for Next Moonwalk Simulations Underway (and Underwater)<\/h1>\n<\/div>\n<\/div>\n<\/div>\n
Some of the same properties of light and optics that make the sky blue and cause rainbows can also help scientists unlock mysteries about cloud formation and the effects of tiny particles in our air.<\/p>\n
NASA\u2019s upcoming PACE mission will offer important insights on airborne particles of sea salt, smoke, human-made pollutants, and dust \u2013 collectively called aerosols \u2013 by observing how they interact with light. With PACE data, scientists will provide better answers to key questions such as how aerosols affect cloud formation or how ice clouds and liquid clouds differ. Understanding the nature of airborne particles and clouds is crucial to deciphering how climate and air quality are changing.<\/p>\n
Two instruments on NASA\u2019s upcoming PACE mission will look at aerosols and clouds \u2013 the A and C in the name of the Plankton, Aerosol, Cloud, ocean Ecosystem satellite. After launch in early 2024, the PACE mission will scan the Earth and gather data on the chemical composition, movement, and interaction of aerosols and clouds through the use of two cutting-edge polarimeters \u2013 instruments that measure light properties.<\/p>\n There are characteristics of light that we can see with our eyes, such as color. Other characteristics are invisible to the human eye, like what scientists call polarization.<\/p>\n \u201cPolarization is something that we don\u2019t have an intuitive sense for because our eyes don\u2019t see it,\u201d said Kirk Knobelspiesse, polarimetry lead for the PACE mission at NASA\u2019s Goddard Space Flight Center in Greenbelt, Maryland. \u201cIf you saw the world through eyes that could see polarization, like our sensors can, you would see rainbows everywhere.\u201d \u00a0<\/p>\n Light leaving the Sun moves in all different directions like a wave \u2013 this is called unpolarized light, said Brian Cairns, deputy project scientist for PACE. When it interacts with something like a cloud or an aerosol particle, however, light can oscillate more in one direction than the others: It is now polarized light. This quirk of light behavior can help scientists learn more about the characteristics and interactions of aerosols and water droplets in the sky.<\/p>\n Polarimeters measure the angle at which the light is polarized, which reveals specific characteristics of whatever the light had bounced off of. With these instruments, scientists can piece together the size, composition, abundance, and other traits of the particles in the atmosphere.\u00a0<\/p>\n The two polarimeters on PACE \u2013 HARP2 and SPEXone \u2013 make a great pair because of the complementary differences in what they measure. HARP2, built at the University of Maryland, Baltimore County, will observe four wavelengths of light from up to 60 different angles. SPEXone, built at the Netherlands Institute for Space Research (SRON) and Airbus Netherlands B.V., will peer down at a narrower swath, using five viewing angles but looking at light at hyperspectral resolution \u2013 the full range of colors in a rainbow. Together the polarimeters will offer a picture of Earth\u2019s atmosphere in unprecedented detail.<\/p>\n Scientists have been observing aerosols from space for decades, though the community has not had polarimetry data for a decade, noted Otto Hasekamp, senior scientist at SRON. PACE will provide polarimeter data from multiple vantage points and, due to technological advancements in the instruments, the data will be of better quality than ever before.<\/p>\n \u201cIt\u2019s exciting to see the culmination of working actively on instrument models and prototypes,\u201d said Jeroen Rietjens, instrument scientist at SRON, \u201cthen finally seeing it end up on a real satellite.\u201d<\/p>\n After PACE is launched in early 2024, the satellite will scan Earth every two days, gathering immense quantities of data on the chemical composition, movement, and interaction of aerosols and clouds.<\/p>\n \u201cWe want to measure properties of aerosols because aerosols affect climate,\u201d said Hasekamp. They reflect light back into space and can also absorb it, which plays a role in how much of the Sun\u2019s energy reaches Earth\u2019s surface. Aerosols also affect cloud formation and properties, but the details of these relationships are not fully known to scientists. The data PACE collects will help to clarify some of these unknowns.<\/p>\n The new polarimetry data will also offer real-time insights on air pollution. \u201cPACE measurements will not only answer fundamental science questions, but will also improve people\u2019s quality of life,\u201d said Marcela Lor\u00eda-Salazar, assistant professor at the School of Meteorology at the University of Oklahoma and PACE early adopter. The PACE Early Adopters program<\/a> promotes the integration of PACE data into practical applications of science.<\/p>\n Lor\u00eda-Salazar is particularly interested in how aerosols change over time and with location, with an extra emphasis on the altitude of aerosols over the middle of the United States. There, PACE will allow scientists to identify aerosols, while also deciphering what they mean for air quality.<\/p>\n The measurements from PACE\u2019s polarimeters will also help improve our understanding of Earth\u2019s climate. By adding PACE atmospheric data to models, scientists will be able to replace the estimates now used to fill data gaps in those models with data from current measurements.<\/p>\n \u201cI\u2019m hoping to help gather the data that will reduce model uncertainty and help us make better predictions for how we expect our climate to play out in the next decades and centuries,\u201d Knobelspiesse said.<\/p>\n By\u00a0<\/strong><\/em>Erica McNamee<\/strong><\/em><\/a>
Download this video in HD formats from NASA Goddard\u2019s Scientific Visualization Studio:\u00a0https:\/\/svs.gsfc.nasa.gov\/14454\/<\/a><\/figcaption><\/figure>\n![\"The](\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2023\/12\/kirk-fogbow.jpg?w=2048\")
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<\/em><\/strong>NASA\u2019s Goddard Space Flight Center<\/strong><\/em><\/a>, Greenbelt, Md.<\/strong><\/em><\/p>\nShare<\/h2>\n<\/p><\/div>\n