Índices pluviométricos na análise da intensidade e variabilidade regional das chuvas no Nordeste do Brasil.

Abstract

Knowledge of the rainfall time series trend in Northeast Brazil ((NEB)is an important information for agricultural planning and water resources. The main objective of this work was to propose a set in rainfall index capable of analyzing the intensity and variability of regional rainfall. These indexes were determined based on 600 daily time series of rainfall on NEB and the trends was evaluated based on the Mann-Kendall test. It was used daily time series of annual rainfall and number of days with rainfall with at last 30 years of data, continuous and flawless. The results show that the semi-arid part of NEB appears more likely the emergence of centers of desertification of the coastal and the northern part of the region. In addition, the dry periods of the semi-arid northeast will become more extensive over the years, and the total rainfall will decrease sharply especially in the dry season. The results also indicate that the states of Pernambuco and Bahia have the longest dry spell of the NEB, nearly a month without rainfall during the rainy season; while Maranhão and Piauí are the states that have the lowest number of consecutive rainless days throughout the region studied.