Global patterns in daytime cloud properties derived from GOME backscatter UV-VIS measurements |
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Authors: | D G Loyola R W Thomas R Spurr B Mayer |
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Affiliation: | 1. Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Methodik der Fernerkundung (IMF), Oberpfaffenhofen , D-82234 , Wessling , Germany diego.loyola@dlr.de;3. Deutscher Wetterdienst (DWD), Hohenpei?enberg Meteorological Observatory , D-82383 , Hohenpei?enberg , Germany;4. RT Solutions, Inc. , 9 Channing Street, Cambridge , MA , 02138 , USA;5. Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosp?hre (IPA), Oberpfaffenhofen , D-82234 , Wessling , Germany;6. Lehrstuhl für Experimentelle Meteorologie, Ludwig-Maximilians-Universit?t , Theresienstrasse 37, 80333 , München , Germany |
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Abstract: | In this paper, we present an overview of the cloud property data set derived from 8 years of reflected solar ultraviolet-visible (UV-VIS) measurements taken by the global ozone monitoring experiment (GOME) instrument from April 1996 to June 2003. We consider four such properties: cloud amount, cloud-top pressure, cloud optical thickness and cloud type. Cloud amounts are generated from GOME broadband polarization data using data fusion techniques, while cloud-top height (pressure) and cloud-top albedo are retrieved from GOME backscatter measurements in the oxygen (O2) A-band via neural network inversion of simulated reflectances. Cloud optical thickness is derived as an additional parameter from the cloud-top albedo and radiative transfer model simulations, and cloud type is determined from the cloud-top pressure and optical thickness. We analyse global and seasonal patterns for these properties, looking at monthly means, standard deviations and the 8-year average values. We compare GOME results with the longer-period multisatellite international satellite cloud climatology project (ISCCP) D-series cloud climatology. The overall good agreement demonstrates that GOME provides accurate and complementary cloud information. Differences in cloud amount, cloud-top height and optical thickness values are due primarily to contrasting measurement strategies (GOME measures daytime-only UV-VIS backscatter, ISCCP is based on several day and night infrared satellite observations). We look forward to the extension of this UV-VIS cloud parameter series with the advent of more recent backscatter atmospheric composition instruments such as the scanning imaging absorption spectrometer for atmospheric cartography (SCIAMACHY) on-board the environmental satellite (ENVISAT) and the GOME-2 series on the MetOp platforms. |
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