Masking of Residual Snow and Ice Covered Surfaces for Improving Aerosol Retrievals From MODIS Data

Aerosol particles in the atmosphere can affect climate directly by interacting with solar and terrestrial radiation and indirectly by their effect on cloud microphysics, albedo, and precipitation. The atmospheric aerosol products have been derived operationally from multi-channel imaging data collected with the moderate resolution imaging spectroradiometers (MODIS) on board the NASA Terra and aqua spacecrafts. Through analysis of several years´ MODIS aerosol products (Collection 4), we have found that the aerosol products over land are slightly contaminated by snow and ice during the springtime snow-melting season. We have developed an empirical technique using MODIS channels centered near 0.66, 0.86 and 1.24 mum and a thermal emission channel near 11 mum to mask out these snow-contaminated pixels over land. Improved aerosol retrievals have been obtained.