Precipitação provável mensal e anual para o Estado do Pará.

Abstract

Considering the scarcity of hydrological information in the literature that may contribute to the development of sustainable irrigated agriculture in Pará and considering the hypothesis that it is possible to represent rainfall frequency distribution through the Gamma function, the present study aimed at adjusting rainfall frequency distributions of localities in Pará state (Brazil) and, based on them, determine and spatialize problable monthly and annual rainfall, with 75% probability. Daily rainfall data were obtained in National Water Agency (ANA) database (153 pluviometric stations). 1,836 historical series of monthly rainfall and 153 annual rainfall series were made. The estimate of probable precipitation was made by Gamma function and this model was approved by the Kolmogorov-Smirnov test in 98.1% of the historical series. Only monthly series failed in the test. The P75% were adequately specialized in Pará state, and the highest rainfall are concentrated in the northeast region with emphasis on the coast of the state and the region near the city of Portel. In the southeast of Pará it was observed that the areas close to Tocantins and Mato Grosso states stayed during five months with predominance of P75% smaller than 50 mm. The probable rainfall of Pará state were adequately estimated and spatialized and the Gamma function can be used to represent therainfall frequency distribution in Pará State, considering that most of the historical series were approved in adherence test.