Análise da variabilidade espaço-temporal da precipitação pluviométrica do estado de Pernambuco utilizando índices climáticos.

Abstract

Climate change is already a global reality and its effects on the environment in which we live are increasingly evident, mainly due to the speed at which they are occurring. Climatic scenarios indicate a greater frequency and intensity of extreme weather events, representing a great threat to the Northeast of Brazil, especially to the state of Pernambuco, which in turn, is commonly affected by periods of intense rain and prolonged drought. Thus, this work aimed to analyze the spatial and temporal variability of rainfall in the state of Pernambuco, as well as the occurrence of extreme rainfall events. Thus, in this study, the following climate indices were used: Precipitation Concentration Index (PCI), Standardized Precipitation Index (SPI), Precipitation Concentration Degree (PCD), Precipitation Concentration Period (PCP) and Rainfall Anomaly Index (RAI), and the tests non-parametric Mann-Kendall and Sen's Slope, for the analysis of trends in precipitation series and climate indices worked. For that, daily rainfall data from the historical series from 1990 to 2020 were used, where data were obtained from the APAC and INMET databases. The results obtained indicated that the east of the state presents a more distributed rainfall throughout the year, presenting itself as "moderately seasonal", in the Metropolitana do Recife and Zona da Mata mesoregions, "seasonal", in the Agreste Pernambucano mesoregion, and "strongly seasonal” in the Sertão Pernambucano and Sertão do São Francisco mesoregions. Through the SPI, it was found that most of the severe and extreme droughts occurred in the 1990s, except in the Sertão do São Francisco mesoregion, where they were predominant in the 2010s. With the RAI methodology, it was possible to identify that there was a higher frequency of negative anomalies compared to positive ones, especially in the last decade, indicating a possible change in precipitation patterns. Trend analyzes indicated that only the SPI-12 showed trends in the Metropolitana do Recife, Agreste and Sertão Pernambucano mesoregions, however, the Sen’s Slope test indicated that the magnitude of these trends are not significant.