Evaluation of the daily rainfall concentration index in Brazil

Abstract

The concentration of rain in short periods can trigger erosion processes and natural disasters such as floods and landslides. In order to investigate the spatial and temporal distribution of daily precipitation throughout the Brazilian territory, the Concentration Index (CI) of daily precipitation was used. 1,402 daily rainfall series were used based on regular records from 1991 to 2020. The results of the annual CI allowed the identification of five climatic zones: 0.7% of the Brazilian territory with CI <0.54 located in the state of Mato Grasso do Sul; 29.4% with CI values between 0.54 and 0.56 located in the central-west region, and in small portions of the south, southeast and north regions; 48.1% with CI values between 0.56 and 0.58 distributed in the south, southeast, north and northeast regions of the Brazilian territory; 14.7% with a CI between 0.58 and 0.60 in the northeast region, and in interior portions of the south and southeast regions; 7.1% with CI values between 0.60 and 0.70 characterized by coastal regions from the north of the state of Santa Catarina to the state of Rio Grande do Norte