Global retrieval of columnar aerosol single scattering albedo from space‐based observations

Abstract

We retrieve the global distribution of columnar single scattering albedo ( ω 0 ) by taking advantage of the high sensitivity of satellite measurements at ultraviolet channels by the Total Ozone Mapping Spectrometer (TOMS) to both aerosol optical depth and ω 0 and the high sensitivity of satellite measurements at visible channels by the Moderate Resolution Imaging Spectroradiometer (MODIS) to aerosol optical depth. A radiative transfer model (LIDORT) is used to calculate the local ω 0 that reproduces the TOMS aerosol index, when constrained by MODIS aerosol optical depth and by relative vertical profiles from a global chemical transport model (GEOS‐CHEM). The simulated aerosol profiles are evaluated with lidar measurements of aerosol extinction. The retrieved ω 0 at 360 nm is near 1 over the remote ocean, in contrast with values of 0.75 to 0.9 over regions dominated by biomass burning and mineral dust aerosol. The retrieval uncertainty is 15%. We validate our retrieval with measurements from the Aerosol Robotic Network (AERONET); the correlation coefficient, slope, and intercept are 0.75, 0.99, and 0.02 respectively.