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Prise en compte des hétérogénéités dans la restitution de l'eau nuageuse et des précipitations par radiométrie micro-onde passive

Abstract : Satellite observations of precipitation by microwave (MW) radiometers are one of the basis for climate study. However, the partial filling of coarse MW radiometer field-of-view causes the underestimation of retrieved quantities (beam-filling effect, BFE). From simulations (cloud and radiation), the relationship between BFE and the sub-pixel cloud fraction (CF) is studied. The results show a cloud type dependency of BFE, and a maximum for low cloud fraction. As CF is the main factor for a correction of rain rate MW retrievals, TB and CF are combined as inputs of a neural network algorithm. MW, IR and radar data have been used to test this approach. Two sub-pixel cloud fractions are defined: the first derived from IR measurements, the second from radar. The results are encouraging and show the advantage of the synergic use of different sensors. In the perspective of a classification embedded in MW retrieval algorithms, a method has been developed for the classification of mesoscale cloud scenes. The classification is obtained from an index based on IR data without clear / cloudy sky threshold
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https://tel.archives-ouvertes.fr/tel-00009275
Contributor : Damien Lafont <>
Submitted on : Tuesday, May 17, 2005 - 1:11:30 PM
Last modification on : Friday, April 5, 2019 - 8:07:51 PM
Document(s) archivé(s) le : Friday, April 2, 2010 - 9:27:39 PM

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  • HAL Id : tel-00009275, version 1

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Damien Lafont. Prise en compte des hétérogénéités dans la restitution de l'eau nuageuse et des précipitations par radiométrie micro-onde passive. Océan, Atmosphère. Université Blaise Pascal - Clermont-Ferrand II, 2005. Français. ⟨tel-00009275⟩

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