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An attempt to retrieve low cloud motion winds over land in the African Monsoon flow on Meteosat pictures
Author(s) -
Désalmand Françoise,
Szantai André,
Desbois Michel
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1998gl900286
Subject(s) - cloud computing , remote sensing , meteorology , monsoon , environmental science , optical flow , histogram , pixel , geology , computer science , geography , image (mathematics) , computer vision , operating system
It has been possible to extract cloud motion winds corresponding to the African monsoon flow during the rainy season over land from the set of all cloud wind vectors provided by a crude cloud tracking method on VIS Meteosat pictures. The selection cannot be based only on IR radiances, due to the presence of semi‐transparent clouds and partial coverages of the pixels. Several tests have been proposed with an additional selection, based on the analysis of the histogram of cloud motion directions. Cloud motion winds obtained on VIS pictures are clearly separated in this diagram and justify the selection of a direction range where only clouds embedded in the monsoon flow are tracked. These winds are also validated by comparisons with NCEP analysed fields.