Análise espaço-temporal da precipitação pluviométrica por Índice de Anomalia de Chuva (IAC) no Sertão de Pernambuco

Abstract

Extreme weather events assume great social and economic relevance, especially in the semiarid regions. The analysis of the rainfall regime of a given region can be done by the Rain Anomaly Index (IAC), which allows understanding and classifying the rainfall regime as to the severity of dry and rainy cycles. The objective of this study was to study the spatio-temporal variability of precipitation in the Sertão de Pernambuco, using the Rain Anomaly Index (IAC) for the climatological normal (1987-2017). For this, rainfall data were obtained from the municipalities of Afogados da Ingazeira, Araripina, Arcoverde, Cedro, Flores, Inajá, Ipubi, Mirandiba, Serra Talhada, Serrita and Sertânia. Annual and interannual precipitation analyzes were performed, negative and positive anomalies were determined throughout the climatological normal and precipitation spatial distribution maps were elaborated in the different annual classifications based on the IAC. The results reveal that in ten of the eleven municipalities studied the rainy season corresponds to the months from January to April. It was found that the years 1993, 1998 and 2012 were the driest in the series, while 1988, 2004 and 2009 were the driest. The number of negative anomalies in the analyzed period was 54.8%, thus showing greater numbers of dry than wet years. It was also found that the Sertão mesoregion has a certain degree of homogeneity in relation to extreme events, i.e., rainy or dry years, when they occur, tend to affect most of the territory. In this work, it was shown that the IAC can be used as a tool to assist climate monitoring and rainfall variability of a given region.