Spatial and Temporal Distribution of Snowmelt Runoff Erosivity in the Black Soil Area of Northeast China

[Objective] Snowmelt erosion is one of the main forms of soil erosion in the black soil area of Northeast China, which plays an important role in land degradation in the area. The erosivity of snowmelt runoff is the key factor for calculating the erosion amount of snowmelt runoff, so it is of great significance to study the erosivity of snowmelt runoff. The erosivity of snowmelt runoff is mainly affected by snow depth, radiation intensity and warming rate, and its main driving forces include snowmelt rate and surface runoff. [Methods] The erosivity of daily average snowmelt runoff in the past 31 years was calculated, the temporal and spatial distribution characteristics of snowmelt runoff erosivity in the black soil area of Northeast China were analyzed, and the main influence factors of snowmelt runoff erosivity in each region were analyzed by using geographic detectors. [Results] The daily average snowmelt runoff erosivity in the three black soil subregions from 1990 to 2020 showed a trend of first increasing and then decreasing, and gradually stabilized in recent years, and the erosivity of daily average snowmelt runoff for many years was 0.01 (MJ·mm)/(hm2·h·a). Spatially, the erosivity of multi-year daily average snowmelt runoff was in the range of 0~0.21 (MJ·mm)/(hm2·h·a), showing a pattern of small in the middle and large in the surrounding areas. The influence factors of snowmelt runoff erosivity in spatial were as follows, the snow depth was large in the north and small in the south, the solar radiation intensity decreased from west to east, and the warming rate decreased from north to south. The influence factor of snowmelt runoff erosivity were analyzed by ground detector, and it was found that the warming rate had the strongest effect in the Mengdong black soil subregion, while the snow depth had the strongest effect in the Songnen black soil subregion and the Sanjiang black soil subregion. [Conclusion] Analyzing the spatiotemporal characteristics and influence factors of snowmelt runoff erosivity in the black soil region of Northeast China from 1990 to 2020 had certain theoretical and practical significance for deepening the study of snowmelt runoff erosivity characteristics and snowmelt erosion prevention in the study area.