Using Space-Borne Lidar to Identify Tropospheric Aerosols

Abstract

An important contemporary problem is the identification of aerosols from space. Ground based lidar systems can use correlative measurements to determine aerosol types but spaceborne lidar systems (such as CALIPSO) rely on models for this identification. Most spaceborne systems (including CALIPSO, MODIS, and OMI) use models based on observations by AERONET, a world- wide network of ground based sun photometers. The aerosol parameters determined by AERONET include the real and imaginary refractive indices, the single scattering albedo and the extinction and absorption Angstrom coefficients. We compare the predictions of the satellite models with AERONET measurements by evaluating the Mahalonibis distances from the model prediction to clusters of aerosols of specific types (such as Urban-Industrial, Biomass Burning, and Dust). We show that some regions do not fit any of the traditional categories; consequently, aerosol identification is problematic. We discuss some of the difficulties associated with aerosol identification from space, specifically considering the CALIPSO system

An important contemporary problem is the identification of aerosols from space. Ground based lidar systems can use correlative measurements to determine aerosol types but spaceborne lidar systems (such as CALIPSO) rely on models for this identification. Most spaceborne systems (including CALIPSO, MODIS, and OMI) use models based on observations by AERONET, a world- wide network of ground based sun photometers. The aerosol parameters determined by AERONET include the real and imaginary refractive indices, the single scattering albedo and the extinction and absorption Angstrom coefficients. We compare the predictions of the satellite models with AERONET measurements by evaluating the Mahalonibis distances from the model prediction to clusters of aerosols of specific types (such as Urban-Industrial, Biomass Burning, and Dust). We show that some regions do not fit any of the traditional categories; consequently, aerosol identification is problematic. We discuss some of the difficulties associated with aerosol identification from space, specifically considering the CALIPSO system