Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 3 3 2010 10.5194/amtd-3-2107-2010 http://www.atmos-meas-tech-discuss.net/3/2107/2010/ http://www.atmos-meas-tech-discuss.net/3/2107/2010/amtd-3-2107-2010.html http://www.atmos-meas-tech-discuss.net/3/2107/2010/amtd-3-2107-2010.pdf 2107 2164 2010-05-12 Retrieval of spectral aerosol optical thickness over land using ocean color sensors MERIS and SeaWiFS W. von Hoyningen-Huene hoyning@iup.physik.uni-bremen.de J. Yoon M. Vountas L. G. Istomina G. Rohen T. Dinter A. A. Kokhanovsky J. P. Burrows Institute of Environmental Physics, University of Bremen, Bremen, Germany For the determination of aerosol optical thickness (AOT) Bremen AErosol Retrieval (BAER) has been developed. Method and main influences on the aerosol retrieval are described together with validation and results. The retrieval separates the spectral aerosol reflectance from surface and Rayleigh path reflectance for the shortwave range of the measured spectrum of top-of-atmosphere reflectance less than 0.670 μm. The advantage of MERIS (Medium Resolution Imaging Spectrometer on ENVISAT) and SeaWiFS (Sea viewing Wide Fiels Sensor on OrbView-2) observations are the existence of several spectral channels in the blue and visible range enabling the spectral determination of AOT in 7 (or 6) channels (0.412–0.670 μm) and additionally channels in the NIR, which can be used to characterize the surface properties. A dynamical spectral surface reflectance model for different surface types is used to obtain the spectral surface reflectance for this separation. Normalized differential vegetation index (NDVI), taken from the satellite observations, is the model input. Further surface BRDF is considered by the Raman-Pinty-Verstraete (RPV) model. 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