Analysis of Aerosol Property Spatial Variability in the San Joaquin Valley During DISCOVER-AQ Field Campaign from High-ResolutionMISR Data

A challenge for space-based instruments monitoring air quality is to distinguish between pollution high in the atmosphere and pollution near the surface, and to quantify the spatial gradients of pollution types. To address this issue, the recent DISCOVER-AQ field experiment in California employed airborne and ground-based aerosol property observations to evaluate existing satellite instruments. The Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA Terra satellite had three overpasses of the San Joaquin Valley during DISCOVER-AQ field campaign on January 20, 27, and February 5 2013. MISR uses a combination of multi-spectral and multi-angle data to retrieve aerosol optical depth (AOD) and particle property information globally at 17.6 km spatial resolution. Using the same algorithm with data collected in all 36-channels at 275 m resolution (Local Mode), which was activated during DISCOVER-AQ field campaign, high-resolution 4.4 km aerosol retrievals were performed in addition to the standard 17.6 km retrievals. In addition, the MISR Research Aerosol Retrieval algorithm was used to perform 1-3 km resolution retrievals with a broad range of aerosol components and mixtures in the algorithm comparison space. We present evaluation and analysis of MISR high-resolution aerosol property data over the San Joaquin Valley during the DISCOVER-AQ field campaign. We use simultaneous AERONET DRAGON ground-based aerosol retrievals to evaluate of quality and spatial consistency of the MISR higher resoltuion retrievals. MISR aerosol type retrievals are further compared with High Spectral Resolution Lidar (HSRL) retrievals, available from collocated B200 flights. In particular, we focus on the January 20 case when stratified dusty aerosol mixtures were detected by HSRL. We demonstrate that MISR high-resolution AOD retrievals are in better agreement with ground-based aerosol observations and reveal greater details about the aerosol spatial variability in the San Joaquin Valley, compared to the MISR standard 17.6 km product. In addition, we investigate the relationship between AOD variability and PM2.5 (particular matter) observations derived from California air quality monitoring stations.