Evaluation of the GPM IMERG half-hourly final precipitation product in the quantification of rainfall erosivity in central Italy

Abstract

The NASA Global Precipitation Measurement (GPM) Integrated Multi-satellitE Retrievals for GPM (IMERG) product is one of the few gridded precipitation products available at a sub-hourly temporal scale. This high temporal resolution is required in many hydrological applications, including the estimation of the rainfall-runoff erosivity factor R, used in the USLE and RUSLE soil erosion prediction models. In this study, through a comparison with data measured at two rain gauges in central Italy, the limits and potential of the GPM-IMERG product on O.t-degree resolution in providing estimates of the R-factor are highlighted. Results indicate that the product can provide accurate estimates in areas relatively homogeneous from an orographic and climatic point of view. On the other hand, it fails to identify the gradients of both precipitation and erosivity that characterize more complex areas, such as those close to the mountain ranges.