Applicability of two satellite-based precipitation products for assessing rainfall erosivity in China

Soil erosion has become one of the most serious environmental problems worldwide, and rainfall is considered a crucial factor in water erosion. Rainfall erosivity is defined as the ability of precipitation to trigger soil erosion. The accurate assessment of rainfall erosivity is essential before taking appropriate measures to stop or slow down water erosion. In this study, we calculated the rainfall erosivity in China using the Xie model and two satellite-based precipitation products (SPPs). Gauge-based data from 2417 stations in China were used for a comparison of the results. We also proposed a procedure to assess the performance of the two SPPs using four statistical metrics and provided recommendations for different sub-regions at different time scales. The results showed that the annual rainfall erosivity based on the IMERG-F and TMPA 3B42-V7 products and the in situ gauge stations were 2014, 1954, and 2138 MJ·mm/(hm²·h·yr), respectively. The spatial correlation between IMERG-F and situ gauge stations is 0.944 and that between the TMPA 3B42-V7 product and situ gauge stations is 0.909. The variation trends of the two were highly similar to those of the gauge-based rainfall erosivity at all time scales. The TMPA 3B42-V7 product is recommended for estimating rainfall erosivity in Haihe River Basin and Huaihe River Basin at monthly scale, in Haihe River Basin and China at seasonal scale, in the Haihe River Basin, Huaihe River Basin, Yellow River Basin at annual scale; while the IMERG-F is recommended for the remaining regions except Continental Basins at the three time scales. Generally, the IMERG-F has broader applicability than the TMPA 3B42-V7 product for estimating rainfall erosivity in China. The results of this study provide a reference for selecting suitable SPPs for rainfall erosivity estimates.