Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 3 2 2010 10.5194/amtd-3-1645-2010 http://www.atmos-meas-tech-discuss.net/3/1645/2010/ http://www.atmos-meas-tech-discuss.net/3/1645/2010/amtd-3-1645-2010.html http://www.atmos-meas-tech-discuss.net/3/1645/2010/amtd-3-1645-2010.pdf 1645 1705 2010-04-12 Speeding up the AOT retrieval procedure using RTT analytical solutions: FAR code I. L. Katsev katsev@light.basnet.by A. S. Prikhach E. P. Zege J. O. Grudo A. A. Kokhanovsky Institute of Physics, National Academy of Sciences of Belarus, Pr. Nezavisimosti 68, 220068, Minsk, Belarus Institute of Environmental Physics, University of Bremen, O. Hahn Allee 1, 28334 Bremen, Germany We present here the aerosol retrieval technique that uses radiative transfer computations in the process of retrieval rather than look-up tables (LUT). This approach provides operational satellite data processing due to the use of the accurate and extremely fast radiative transfer code RAY previously developed by authors along with approximate analytical solutions of the radiative transfer theory. The aerosol optical thickness (AOT) and Angström exponent are optimized in the iteration process using the least-squares technique with fast computations of the derivatives of radiative characteristics in respect to retrieved values. The developed technique can be adapted for processing data of various satellite instruments (including any spectral multi-angle polarization-sensitive sensors). <br><br> Beside, two important problems that determine the accuracy of the AOT retrieval are considered. The first one is the effect of the preliminary choice of the aerosol model, particularly for retrieval from satellite instrument providing only spectral data (MERIS, MODIS). The second problem is the influence of clouds in adjacent pixels. 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