Use of a high-resolution-satellite-based precipitation product in mapping continental-scale rainfall erosivity: A case study of the United States

Abstract

A rainfall erosivity map is useful for understanding the spatial variability of rainfall erosivity, and for identifying regions vulnerable to soil erosion by rainfall. This study addresses a new approach to mapping rainfall erosivity on a continental scale, based on a high-resolution-satellite-based precipitation product—the National Oceanic and Atmospheric and Atmospheric Administration’s Climate Precipitation Center morphing technique (CMORPH). For this purpose, a rainfall erosivity map of the contiguous United States is experimentally developed, and is analyzed from the perspectives of the corresponding hydrological basins and climate features. In general, we conclude that the CMORPH precipitation product is useful for mapping rainfall erosivity on a continental scale. In the contiguous United States, the mean of rainfall erosivity was 1260 MJ mm ha−1 h−1 yr−1, with high variability by region. The coastal regions showed the highest rainfall erosivity, at 20%. The seasonality of the rainfall erosivity was evident in most coastal regions (rainfall erosivity depends on climates). The rainfall erosivity in the tropical climate zone was the highest, whereas it was the lowest in the arid climate zone (and spatially homogeneous). However, corrections were required for improving the accuracy of the CMORPH precipitation in most coastal regions, i.e., to secure a better rainfall erosivity product. Compared to a rain gauge-based rainfall erosivity map, the CMORPH’s rainfall erosivity map tended to underestimate the rainfall erosivity in coastal regions near the Gulf of Mexico and Atlantic Ocean, but overestimated it in coastal regions near the Pacific Ocean.