Spatio-temporal assessment of extreme precipitation events in southeastern Brazil

Abstract

Climate change is a phenomenon directly attributed to human activity due to greenhouse gas emissions and changes in land use and land cover. In this way, climate change has and will have direct and indirect impacts on the components of the climate systems, including the hydrological cycle, through an increase in the frequency and intensity of extreme events, such as heavy rains or droughts, which impact natural systems, groups, and human systems, as well as on economic activity, such as the energy, agricultural and water sectors that are directly dependent on the variables of the hydrological cycle. The southeast region of Brazil (São Paulo, Minas Gerais, Rio de Janeiro, and Espírito Santo) produces 60\% of the national wealth and much of the country's electricity, in addition to housing 80 million people. Extreme weather events have hit this region in recent decades, causing an increasing number of natural disasters. Good examples are the 2014/15 water crisis and the occurrence of heavy rains, particularly in the summers. Given the importance of this theme, the present study aims to analyze the spatial and temporal variability of precipitation over southeast Brazil through the Generalized Extreme Values (GEV) distribution. To this end, seasonal variability and changes in the patterns of precipitation extremes in the period 1981-2020 were analyzed, based on data obtained from the CPC (Climate Predict Center). This research revealed that the frequency and intensity of extreme rainfall events have been changing, notably decreasing during winter.