Influence of typhoons on the spatiotemporal variation in rainfall erosivity in the Pearl River Basin

A typhoon can change the rainfall pattern over its path. Exploring the impact of typhoons on rainfall erosivity (RE) is very important for the prevention and control of soil erosion in key areas of the Pearl River Basin. Based on the long-term daily rainfall products from 1960 to 2020 and the GPM high-resolution rainfall products from 2001 to 2020, the Mann-Kendall test, Bernaola Galvan segmentation algorithm, and spatial autocorrelation are used in this study to analyze the spatiotemporal variation characteristics of RE and the influence of typhoons. The results indicate that (1) RE has obvious spatiotemporal heterogeneity. The average annual RE is 11,314.10 MJ·mm·ha−2·h−1. The RE shows an upward trend of 8.63 MJ·mm·ha−2·h−1/year, and this study shows that an abrupt change point occurred in 1992. In addition, the RE decreases from southeast to northwest, showing an extremely significant agglomeration near the delta. (2) The spatiotemporal variations in typhoon RE are different from those of the RE across all periods. Typhoons slow the increase in RE, change the abrupt change points, and increase the degree of agglomeration. There are significant resonance periods between typhoons and RE. (3) RE is significantly correlated with the typhoon potential risk index. Typhoons affect RE by increasing precipitation, the rainfall duration, and rainfall kinetic energy. This study explores the importance of typhoons to the spatiotemporal variations in RE, which is crucial for identifying soil erosion risks and formulating prevention and control strategies under extreme climate impacts.