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

Abstract

We retrieve the global distribution of columnar single scattering albedo (ω0) 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 ω0 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 ω0 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 ω0 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.