Robust observational quantification of the contribution of mesoscale convective systems to rainfall in the tropics
Résumé
Satellite estimation of precipitation and satellite derived statistics of Mesoscale Convective Systems (MCS) are analyzed conjunctively to quantify the contribution of the various types of MCS to the water budget of the tropics. The study focuses on two main mesoscale characteristics of the systems: duration and propagation. Overall, the systems lasting more than 12h are shown to account for around 75% of the tropical rainfall. 60% of the rainfall is due to systems traveling more than 250km, a typical GCM grid. A number of regional features are also revealed by factoring in the convective systems' morphological parameters in the water budget computation. These findings support the challenging effort to account for such mesoscale features when considering the theory on the future evolution of the water budget as well as the physical parameterizations of climate models. Finally, our analysis provides a simple metric for evaluating high resolution numerical simulations of the tropical water budget. Furthermore, our results are shown to be robust to the selection of the satellite rainfall products.
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