Index of rain aggressiveness and erosivity in different climate types in Brazil

Abstract

Heavy rains are responsible for triggering erosion processes and landslides. Knowledge of the spatial variation of rainfall aggressiveness makes it possible to plan land use and propose prevention and mitigation measures. This work aims to evaluate the rainfall aggressiveness indices and relate them to the climatic types in Brazil. Estimated monthly precipitation data were used for each Brazilian municipality and the Fournier (IF), Modified Fournier (IFM) and Total Erosivity Index (TEI) indexes were calculated. The data were geoprocessed and correlated with the climate types in Brazil, according to the Köppen classification. The IF ranged from 7.3 to 110.5 with 47.5% of the territory classified as “Moderate erosivity”. The IFM ranged from 48 to 388 with 76% in the “Very High” erosivity class and 16.0% “High”. The climate types Af, Am Cfb, Cwa and Cwb are classified as “Moderate erosivity” or higher. The TSI ranged from 444 to 4977 and 54.3% had “High” erosivity and 31.5% “Moderate”. The climate type Am presented the highest mean TSI followed by Aw, Af, As, CWa and Cwb, with TSI above 2000. The lowest TSI values ​​were observed in the Cfa and Cfb climates, followed by the BSh climate.