Characterization of Some Elements of the Sahelian Climate and Their Interannual Variations for July 1983, 1984 and 1985 from the Analysis of METEOSAT ISCCP Data

Abstract

METEOSAT infrared and water vapor radiance data from the ISCCP dataset are used to describe climatic characteristics for the months of July 1983, 1984 and 1985, corresponding to very different rainy seasons in Sahelian Africa. Mean cloudiness distribution diurnal cycle of local convection, life cycle of squall lines and drift velocities computed from WV images are studied. The results and their interannual variations are shown to be consistent with analyses from other data sources, including conventional data. The utilization of both kinds of analyses allows not only the validation of the satellite approach but also an improved description of the climatic situations as different parameters are inferred. The main cloud systems and circulation differences between the driest and the wettest months studied are in general agreement with previous observational and simulation studies comparing dry and wet years. Abstract METEOSAT infrared and water vapor radiance data from the ISCCP dataset are used to describe climatic characteristics for the months of July 1983, 1984 and 1985, corresponding to very different rainy seasons in Sahelian Africa. Mean cloudiness distribution diurnal cycle of local convection, life cycle of squall lines and drift velocities computed from WV images are studied. The results and their interannual variations are shown to be consistent with analyses from other data sources, including conventional data. The utilization of both kinds of analyses allows not only the validation of the satellite approach but also an improved description of the climatic situations as different parameters are inferred. The main cloud systems and circulation differences between the driest and the wettest months studied are in general agreement with previous observational and simulation studies comparing dry and wet years.