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Cycle de vie des systèmes convectifs de mousson dans les régions tropicales: préparation à la mission Megha-Tropiques    

Abstract :   The main objective of this work is to study the monsoonal convective systems by using meteorological satellite observations. For this purpose, a new algorithm called TOOCAN based on a three dimensional segmentation of the IR imagery has been developed in order to detect and track objectively and automatically convective systems. This new technique improves the characterisation of the cold cloud shield associated to convective systems along their life cycles. Composites of precipitating structures along the cycle life of organized cloud systems are then computed by merging geostationary satellite data with precipitating estimates derived from microwave measurements on board low earth orbit satellites. These techniques are then applied to the IR data from METEOSAT and microwave data from the TRMM satellite over several monsoonal seasons in West Africa and India. On the whole monsoonal region, the results show that the temporal evolution of the cold cloud shield associated to convective systems describes a symmetry between the growth and the decay phases. It is also shown that the parameters of this conceptual model of monsoonal convective systems are strongly correlated, reducing thereby the problem to a single degree of freedom. The evolutions of the precipitating area fraction and the convective rain fraction associated to convective systems indicate that the life cycle of these systems can be described by three phases: initiation, mature and dissipation. This pattern is robust across the entire monsoonal region and the scale factors of this idealized model indicate complex regional specificities.
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https://pastel.archives-ouvertes.fr/pastel-00576870
Contributor : Thomas Fiolleau <>
Submitted on : Tuesday, March 15, 2011 - 3:08:14 PM
Last modification on : Friday, October 23, 2020 - 5:03:50 PM
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  • HAL Id : pastel-00576870, version 1

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Thomas Fiolleau. Cycle de vie des systèmes convectifs de mousson dans les régions tropicales: préparation à la mission Megha-Tropiques    . Climatologie. Ecole Polytechnique X, 2010. Français. ⟨pastel-00576870⟩

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