Satellite Remote Sensing of Air Quality from Geostationary Orbit

Abstract: Remote sensing from satellite instruments has enabled global measurements of trace gases and aerosols in the Earth’s atmosphere. These observations allow us to examine the global distribution of trace gases relevant to air quality and climate, to estimate emissions from natural and anthropogenic sources, and to study the transport of atmospheric pollution. Satellite instruments measuring backscattered ultraviolet and visible radiation are particularly sensitive to the atmosphere near the Earth’s surface, and are used to detect several trace gases of importance to air quality, including ozone, nitrogen dioxide, sulfur dioxide and formaldehyde. These observations are currently made by a suite of sun-synchronous satellite instruments, which typically measure a location once per day with a spatial resolution of tens of kilometers. The next generation air quality missions are scheduled to launch within the next five years into geostationary orbit, and will provide hourly observations with spatial resolutions on the order of 2×4 km ² . Our group at the Harvard-Smithsonian leads the development of TEMPO (Tropospheric Emissions: Monitoring of Pollution), the North American component of this global air quality satellite constellation, which will make measurements over Canada, the U.S. and Mexico. In this talk, I will discuss the techniques we use to determine trace gas observations from these current and future instruments, and present observations from NASA’s two geostationary mission airborne simulators, which have produced the first high spatial resolution maps of trace gases over U.S. and Korean cities and industrial sites.