Abstract:

Based on daily precipitation data for the table land-protected area,this paper analyzed temporal and spatial variation and trends and explored the main factors influencing rainfall erosion according to Mann-Kendall analysis,wavelet analysis and statistical methods.Results reveal as follows:(1) The average annual rainfall of the Loess Plateau protected area in Shanxi,Shaanxi and Gansu Provinces,China over the past 60 years is 599.2 mm,the average annual rainfall erosivity is 1 871.91 MJ·mm·hm^-2·h^-1·a^-1,and the rainfall erosivity is.There has been a slight upward trend over the past 60 years and seasonal differences have changed significantly.(2) The spatial distribution of rainfall erosivity in the Loess Plateau protected area is found to generally decrease from the south to both sides.The Mann-Kendall Z value shows a downward trend except for the northern and eastern parts of the study area,while all other regions show an upward trend.(3) The rainfall erosivity of the Loess Plateau protected area has a long period of 32 years,also showing 13 years and 52 years of shorter periods during the time period studied.(4) Of the main atmospheric circulation factors affecting the midhigh latitudes in the northern hemisphere,only the factor reflecting the fluctuation of cold and warm episodes by season has a significant effect on rainfall erosion of the entire region and the Shaanxi highland.There is a negative correlation between the two and the remaining circulation index.There is found to be no significant correlation with rainfall erosion;in addition,sunspots show a positive correlation with the change law of precipitation erosion in Shaanxi plateau area,but no significant correlation with the other plateau areas.

Key words: Loess Plateau, rainfall erosion, spatial and temporal distribution, influence factor