Distribuição da precipitação na cidade do Rio de Janeiro a identificação de eventos extremos

Abstract

The objective of this research is to identify changes in the distribution of extreme precipitation events in the city of Rio de Janeiro. To fulfill this purpose, a methodology was applied based on the RClimdex software, allowing to verify if there were changes in the distribution of precipitation 11 indexes made available by the Climate Change Detection and Indices (ETCCDMI) platform related to climate change, from 1997 to 2017 in 15 spatially distributed rainfall stations in the city of Rio de Janeiro / RJ. Subsequently, these indices were submitted to linear regression, segmented linear regression, coefficient of determination (r2), standard error of estimation and t-test for the angular coefficient of the line. The results showed that the total annual precipitation index of the city of Rio de Janeiro changed in 2007/2008, demonstrated by the segmented linear regression. Rainfall increase was verified from the beginning of the analyzed period until approximately 2007/2008. From 2008 onwards, it was observed a reduction in the annual total of precipitation until the end of the series analyzed in 2017. Most of the stations analyzed showed the same pattern in the other indexes evaluated over the twenty years and few showed statistical trends. significant. Overall, these results indicated a decrease in rainfall over the past 10 years and a decrease in extreme precipitation events. The extremely humid days (R99p) and the maximum total daily precipitation (Rx1day) increased in the years 1997 to 2017, which may contribute to the increase of extreme precipitation events in the region.