DocumentCode :
1210617
Title :
Angular distribution models, anisotropic correction factors, and mixed clear-scene types: a sensitivity study
Author :
Bertrand, Cédric ; Clerbaux, Nicolas ; Ipe, Alessandro ; Dewitte, Steven ; Gonzalez, Luis
Author_Institution :
Dept. of Obs., R. Meteorol. Inst. of Belgium, Brussels, Belgium
Volume :
43
Issue :
1
fYear :
2005
Firstpage :
92
Lastpage :
102
Abstract :
Because radiometers do not measure the earth´s outgoing flux directly, angular distribution models (ADMs) are used to invert measured radiances at the top of atmosphere (TOA) to flux. However, data used to build ADMs are generally not sorted for mixed scene types, and anisotropic correction factors for such scenes are not usually available. In the present study, we have analyzed shortwave (SW) flux values retrieved over nine areas representative of a junction between two different ADM scene types in the Meteosat-7 field of view. The Clouds and the Earth´s Radiant Energy System (CERES) broadband SW ADMs were used to perform the radiance-to-flux conversion. Because of the large anisotropy difference that can exist between ADMs, use of the ADM that corresponds to the scene type with the highest percent coverage over footprints containing a mixture of scene types generates instantaneous as well as systematic errors in the retrieved SW flux values. Nevertheless, in the absence of available mixed scene type ADMs, we show that the CERES on the Tropical Rainfall Measuring Mission satellite SW ADMs can be combined together to provide reliable mixed scene types anisotropic correction factors. The use of such anisotropic factors appears to be especially well suited along the coastline of continents.
Keywords :
atmospheric techniques; microwave measurement; radiative transfer; radiometry; remote sensing; sunlight; CERES; Clouds and the Earth´s Radiant Energy System; Earth; Meteosat-7; Tropical Rainfall Measuring Mission satellite; angular distribution models; anisotropic correction factors; continent coastline; mixed clear-scene types; radiance inversion; radiance-to-flux conversion; radiometers; remote sensing; sea ice; shortwave flux values; solar radiation; top of atmosphere; vegetation; Add-drop multiplexers; Anisotropic magnetoresistance; Atmosphere; Atmospheric measurements; Atmospheric modeling; Clouds; Earth; Layout; Radiometers; Satellite broadcasting;
fLanguage :
English
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
Publisher :
ieee
ISSN :
0196-2892
Type :
jour
DOI :
10.1109/TGRS.2004.838361
Filename :
1381625
Link To Document :
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