Análise de tendências de índices de mudanças climáticas na precipitação do estado de Pernambuco

Abstract

Many studies shown that the increase in the planet’s average temperature causes the hydrological cycle to intensify. This could cause changes in rainfall patterns, such as an increase in the frequency and intensity of extreme events resulting in severe and prolonged droughts in some locations and excessive rainfall in others, which would significantly impact the hydrological availability of a region and the quality of life of its inhabitants. Thus, it is necessary to study the variability and impacts of climate change, enabling a better understanding of the area’s climate in order to adapt and mitigate these climatic conditions. In this context, the present work aimed to analyze the trends and magnitudes of 11 extreme weather indices recommended by the Expert Team on Climate Change Detection Monitoring and Indices for the state of Pernambuco. For this, 809 grid points were used, which contain information regarding daily rainfall from 1961 to 2020 and three non-parametric methods were employed: the Mann-Kendall test for trend detection, sen’s slope for estimating the magnitude of the trend, and the Mann-Whitney-Wilcoxon test to assess whether there are significant differences in the index values for each region of Pernambuco: Zona da Mata, Agreste, and Sertão. In addition, the Inverse Distance Weighting interpolator was used to perform the spatial analysis of precipitation and extreme weather indices. The results indicated an intensification of drought over much of the state, with significant reductions in total annual precipitation, consecutive wet days, and an increase in consecutive dry days. The trends show an acceleration in the desertification process in the Sertão region, which is part of the semi-arid Northeast and already suffers from scarce and poorly distributed rainfall. In relation to the Zona da Mata, the extreme rainfall indices showed significant increases, alerting us to the natural disasters that affect this region. The Agreste region showed similar results to the Zona da Mata, but with less intensity. Based on the results obtained it is possible to infer that the study area tends to become drier, with rainfall increasingly concentrated in shorter periods of time, and the dry periods interspersed between these rainfall events are becoming longer.