An estimation of the contribution from TRMM-identified extreme storms to the total precipitation in South America
The TRMM PR data are first used to investigate the relative contribution of precipitation from the TRMM-identified echo cores to the full storms in which the echo cores are embedded within on regional, seasonal, and diurnal scales by each separate storm type. The second part of the study assesses how much of the climatological rainfall in South America is accounted for by storms containing deep convective, wide convective, and broad stratiform echo components. Systems containing these echoes produce very different hydrologic responses. Extreme storm events with stratiform and convective elements lead to some of the highest rain contributions in specific regions throughout South America. Over 50% of the rain in subtropical South America from the austral fall through spring is contributed by extreme convective elements. During the austral warm season, regions that experience frequent mesoscale convective systems (MCSs) in the subtropics have convective rain contributions ranging from 50-60% of the total climatological rain. These numbers are very comparable to other precipitation contribution studies for warm season MCSs in the United States. From a hydrologic and climatological viewpoint, this empirical knowledge is critical, as the type of runoff and flooding that may occur depends on the specific character of the convective storm and has broad implications for the hydrological cycle in this region.