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A Validation of Solar Backscatter Radiances using Antarctic Ice

Glen Jaross(1), Jeremy Warner(1) and Marcel Dobber(2)

(1) Science Systems and Applications, Inc., 10210 Greenbelt Road, Lanham, MD 20706, United States
(2) Royal Netherlands Meteorological Institute (KNMI), PO Box 201, 3730 AE DeBilt, Netherlands


In this presentation we discuss our approach to validation of sun-normalized radiance measurements from polar-orbiting, UV/VIS spectrometers. In particular, we have evaluated the OMI and TOMS sun-normalized radiances at wavelengths greater than 330 nm, and the four shortest MODIS/Aqua bands. Our analysis should be equally applicable to SCIAMACHY up to 800 nm. The technique involves comparing normalized radiances measured over the Antarctic continent with top-of-the-atmosphere (TOA) values computed with a radiative transfer model. In our model we assume a pure Rayleigh-scattering, aerosol-free, cloud-free atmosphere, and a mean surface reflectance derived from measurements on the ground. TOA radiances are sensitive to the bi-directional distribution of surface reflectance, especially at high solar zenith angles. We have developed a surface reflectance model to help correct these effects, but it still remains the largest source of uncertainty. We estimate the residual uncertainty at all wavelengths to be 2/%.


Workshop presentation

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry