New gridded dataset of rainfall erosivity (1950–2020) on the Tibetan Plateau

Abstract. The risk of water erosion on the Tibetan Plateau (TP), a typical fragile ecological area, is increasing with climate change. Rainfall erosivity maps are useful for understanding the spatiotemporal patterns of rainfall erosivity and identifying vulnerable regions. This study generated a gridded annual rainfall erosivity dataset of the TP for 1950–2020 using a new approach based on 1-min precipitation observations at 1787 weather stations and 0.25° hourly European Center for Medium-Range Weather Forecasts Reanalysis 5 (ERA5) precipitation data. We conclude that ERA5 is generally useful for mapping annual rainfall erosivity on the TP, considering the high correlation coefficient and consistent spatiotemporal patterns between the ERA5-based and observed annual rainfall erosivity. In addition, obvious underestimation of the ERA5-based annual rainfall erosivity was found. After correction by a multiplier factor map, the annual rainfall erosivity values for 2013–2020 are in good agreement with the observed values in terms of the correction coefficient and probability density. Finally, a new annual rainfall erosivity dataset for 1950–2020 was produced after the ERA5-based annual rainfall erosivity values were corrected. We found that the area-averaged mean annual rainfall erosivity on the TP is 307 MJ·mm·ha−1·h−1 and tends to decrease from southeast to northwest. Key regions with large rainfall erosivity potential are concentrated in the Bomi–West Sichuan and Dawang–Chayu areas. This new annual rainfall erosivity dataset could extend our knowledge of rainfall erosivity patterns and provide fundamental data for quantifying soil erosion in the TP.