Contribuição ao estudo da distribuição de chuva no Estado do Rio Grande do Norte.

Abstract

A simple method is proposed in order to discriminate three different rainfall conditions — designated as "pessimistic", "normal" and "optimistic" — according to the most fre quent rainiest semester and three-month periods. The empirically fixed discriminating criteria to identify those conditions are based on the total precipitation of the semester and three month periods , corresponding to selected probability levels (P < 25%, 25% <_ P <_ 75% and P < 75%) , using the incomplete gamma distribution model proposed by MIELKE (1975). Rainfall data collected in the State of Rio Grande do Norte, Brazil, from about 69 stations with more than 20 years of recording period were used. Charts of percentual contribution of the rainiest semester and three-month periods are also included, as well as annual mean values charts of water sur plus and deficiency, estimated through the THORNTHWAITE & MATHER's methodology (1955) for the three above mentioned conditions .