On the duration and life cycle of precipitation systems in the tropics

Abstract

After decades of active research, knowledge of the precipitating mesoscale convective systems has made strong progress based on many regional investigations. Yet a tropical-wide perspective on these systems is only recently emerging thanks to satellite observations. This chapter is dedicated to this tropical view with an emphasis on the duration and the life cycle of precipitating system that are physically sound characteristics of the organization of the system. The more organized systems are dominating the contribution to the precipitation totals despite their low occurrence. It is shown that the systems lasting more than 12 h correspond up to 70% of the precipitation. At the system scale, the recent satellite observations dedicated to precipitation allow for a new appraisal of the conceptual model of mesoscale convective system (MCS) initiation, mature stage and dissipation. A preliminary quantification of the precipitation, latent heating and radiative cooling evolution within the life cycle of the MCS suggests the importance of the latent heating process in the first half of the system lifetime. In the second part, the radiative cooling needs to be accounted for to draw a complete picture of the energy budget of the systems.