Seth, A., M. Rojas, B. Liebmann, and J.-H. Qian, 2004: Daily rainfall analysis for South America from a regional climate model and station observations. Geophys. Res. Lett., 31(7), L07213, 10.1029/2003GL019220, 4pp.


Seasonal rainfall prediction, while useful for some planning, does not have the temporal resolution required for many applications. Information regarding sub-seasonal variations in rainfall is often needed for water management and agriculture sector decisions. Daily station observations are used to characterize rainfall frequency and intensity and to verify a regional climate model (RegCM). The model is driven by reanalyses and by general circulation model ensemble realizations for two anomalous seasons in South America. Rainfall distributions simulated by the RegCM slightly overestimate smaller events at the expense of large events in the Northeast and Amazon, yet the smallest rainfall events are generally well represented. Importantly, the RegCM captures the shift in the rainfall distribution which occurs between 1983 (more small events) and 1985 (more large events). The sensitivity of these results to periodic reinitialization show some promise. These results imply that regional models may provide useful statistics on the subseasonal character of rainfall, however, longer nested integrations are needed.