The evolution of spatial and temporal distribution of rainfall erosivity in Henan Province, central China

With the development of urbanisation, arable land has been drastically reduced and soil has been eroded, which has a negative impact on the food economy and agricultural development in some areas. Henan Province covers four basins, the Yangtze River, the Yellow River, the Huaihe River, and the Haihe River, with complex water conditions, and is a key agricultural region in China. Therefore, this paper uses 53 years of day-by-day rainfall data from 1969–2022 at 112 rainfall stations in Henan Province, and adopts the Zhang Wenbo erosivity model and the rainfall erosivity model of the First National Water Conservancy Census to calculate the erosive power of rainfall and combines with the multi-year The average rainfall was analysed using the Kriging interpolation method in the Geostatistical Wizard of ArcGIS, and the corresponding spatial distribution maps of rainfall and rainfall erosive force were derived. Wavelets and Mann-Kendall were used to analyse the fact of sudden changes, trends and cycles of rainfall and rainfall erosivity in the study area. Theresults show that the average rainfall (1969–2022) in Henan province is 718.26 mm, and the average rainfall erosivity ( R ) is 3213.46 MJ·mm/(hm 2 ·h). R values are positively correlated with rainfall intensity and amounts, and show an upward trend year by year. The spatial distribution of R shows a gradual increase from northwest to southeast, which is closely related to the topography. There is a cyclic change in the rainfall in the study area, with the first primary cycle being the first cycle in every 53 years. The results of the study can be useful for other regions in central China.