Properties of deep convection in tropical continental, monsoon, and oceanic rainfall regimes



[1] This study compares vertical structures and properties of deep convection for continental, monsoonal, and oceanic rainfall regimes based on 13-yr TRMM measurements. There is evident regime separation in convective structures and properties of deep convection: continental and oceanic regimes are at two ends of the spectrum, with monsoon regimes intermediate between them. For example, most of the continental rainfall (70–80%) is contributed by storms having 40-dBZ radar echoes reaching above 6-km, strong ice scattering signature, and lightning flashes. This indicates that continental convection is dominated by robust mixed-phase processes such as freezing of raindrops or riming of graupel supported by strong updrafts. In contrast, less monsoon rainfall (∼40%) or very limited oceanic rainfall (∼10%) involves these vigorous microphysical processes in mixed-phase regions. Though monsoons are intermediate in convective intensity, both current and previous studies show that their active periods are closer to oceanic regimes and their break periods are slightly closer to continental regimes. In short, this study offers novel guidance for categorization of convective properties of three regime archetypes and will be important for future regional, climatological, and modeling studies.