Aerosol retrieval fort the Multi-Spectral Imager (MSI) on EartCARE
Wolfgang von Hoyningen-Huene(1), Gerard Hesselmans(2), Gerrit de Leeuw(3), Alexander A. Kokhanovsky(1), Leslie Gale(2) and John P. Burrows(1)
(1) University of Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany
(2) BMT ARGOSS, Voorsterweg 26, 8316 PT Marknesse, Netherlands
(3) Finnish Meteorological Institute, Erik Palmenin Aukio 1, P.O. Box 503, FI-00101 Helsinki, Finland
The Multi Spectral Imager (MSI) is planned as an instrument of the future ESA EarthCARE mission to observe the atmospheric conditions in the surrounding of the main profiling instruments, the atmosphere Lidar in space (ATLID) and the cloud and precipitation radar (CPR) and the broad band radiometer (BBR). Since one goal of the EarthCARE mission is the investigation of aerosol conditions, a retrieval of aerosol optical thickness for the observation and instrument conditions of the MSI instrument is required.
In preparation of the future mission, the development of aerosol retrieval algorithms has been started as part of the ESA ITT AMARSI (Aerosol Modelling and Retrieval from Multi-Spectral Imager). The first step was a retrieval approach for aerosol optical thickness (AOT) over ocean together with the associated target discrimination. It is based on the MSI channels 1 – 4, in visible (0.659 µm) and NIR (0.865, 1.64 and 2.20 µm) and give the AOT for channels 1 and 2. Channel 4 is used for the correction of water surface contribution. The algorithm determines aerosol reflectance from the observations, performs corrections for Rayleigh path reflectance and the surface influence. Look-up-tables are generated, using forward model calculations to obtain AOT from aerosol reflectance.
The algorithm has been tested with synthetic data, generated from the forward model and with real satellite observations, prepared from selected MODIS channels, according the MSI settings.