Downscaling the resolution of the Rainfall erosivity factor to soil erosion calculation in watersheds to Atlantic Forest biome, Brazil

The calculation of the R-factor (Rainfall erosivity) for implementation in soil erosion models such as USLE (Universal Soil Loss Equation) and RUSLE (Revised Universal Soil Loss Equation) encounters substantial difficulties due to the scarcity of spatial databases in adequate resolution for actions of territorial planning at the local level. Otherwise, there is a spatial database available with a coarse resolution of themes that can be used to calculate the R-factor. We apply the spatial downscaling, based on regression models: linear (LN), general additive model (GAM), random forest (RF), cubist (CU), on erosivity data (target variable) prepared for the State of São Paulo, Brazil, with a spatial resolution of 2,500 m. We used DEM and slope data with 30 m fine-resolution from the Atibaia watershed, located between the metropolitan regions of São Paulo (RMSP) and Campinas (RMC) to apply the downscaling. This framework improved the spatial resolution of the R-factor, necessary to calculate soil loss in the USLE and RUSLE equations in a territory where the scarcity of data with the fine resolution is still limited to the development of territorial planning projects at the local level. The RF model was better with R² 0.93.