AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Spatial Distribution of Aerosols in Four U.S. Regions: Impacts on Satellite Measurements
ANDREAS BEYERSDORF, Luke Ziemba, Timothy A. Berkoff, Sharon P. Burton, Gao Chen, James Collins, Anthony L. Cook, Chelsea Corr, Suzanne Crumeyrolle, Marta Fenn, Richard Ferrare, Johnathan Hair, David B. Harper, Chris Hostetler, Jack J. Lin, Robert Martin, Richard Moore, Raymond R. Rogers, Amy Jo Scarino, Shane Seaman, Michael Shook, Kenneth Thornhill, Edward Winstead, Bruce Anderson, NASA Langley Research Center
Abstract Number: 681 Working Group: Urban Aerosols
Abstract Aerosol measurements from satellites in geosynchronous orbit allow a unique opportunity to measure urban air quality at high spatial and temporal resolution. Typical measurements of air quality are based on ground sites spaced sporadically within urban areas. While these offer high quality temporal measurements of air quality, their spatial coverage is limited. Conversely, satellites in low earth orbit can provide measurements over the entire globe but give limited information on the temporal nature of air pollution. However, geosynchronous satellites will be able to measure air quality throughout the day for a specific region of interest (such as North America for the planned NASA TEMPO satellite). A key constraint of satellite measurements is the spatial resolution of the retrieved data products. As the satellite footprint increases, the precision of aerosol properties improves; however, the ability of the satellite to measure small-scale variations in pollution diminishes. Currently, TEMPO is planned to measure aerosol optical depth (AOD) with a spatial resolution of 36 square-km. In this study, sub-pixel variability is used as a metric of how representative the satellite measurement is of ground-based air quality.
Data from the DISCOVER-AQ airborne project are used to determine the sub-pixel variability in AOD, boundary layer extinction and other aerosol properties in four U.S. regions: Baltimore, Maryland, Houston, Texas, Denver, Colorado, and California’s San Joaquin Valley. Sub-pixel variability in boundary layer extinction was lowest in Denver (one sigma variability of 3 /Mm at 36 square-km spatial resolution) due to low aerosol loadings and highest in the San Joaquin Valley (19 /Mm) due to variable boundary layer depths and stagnant conditions. Variability in AOD (measured by an airborne high-spectral resolution lidar) was more consistent amongst the sites (0.017 to 0.035) because it is a measure of column loadings and hence not dependent on boundary layer depth changes.