| The wide application of satellite-based and reanalysis-based precipitation data has greatly promoted hydrometeorological research in areas where precipitation observations are scarce.However,the suitability of such precipitation products needs to be carefully evaluated before applications in certain basins because their inherited errors vary with different climate zones,seasonal cycles and land surface conditions;in addition,the watershed runoff is the main energy driver of soil erosion.Although the basin runoff is widely used to explore the spatial distribution characteristics of runoff erosion,there are still some limitations that cannot be avoided.It can better reflect the spatial distribution of runoff erosion by using runoff erosion capability from the perspective of energy.In this paper,we systematically evaluate the effects of satellite-based precipitation products(Tropical Rainfall Measuring Mission(TRMM)and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record(CDR))and reanalysis-based precipitation products(China Meteorological Assimilation Driving Datasets for the Soil and Water Assessment Tool(SWAT)model(CMADS)and National Centers for Environmental Prediction-Climate Forecast System Reanalysis(CFSR))on runoff simulation for the first time in the Xihe River Basin,China.And analyze the spatial variabilities between runoff erosion capacity and underlying surface factors by combining spatial gradient analysis and GWR(Geographically Weighted Regression)analysis.The major conclusions of this research can be summarized as follows:(1)The trend of precipitation was relatively stable,and the trends of annual runoff and annual sediment runoff showed a significant downward during the period from 1976 to 2015 in the Xihe River Basin.The precipitation was mainly concentrated in May.-Sept.and peaked in Jul.The runoff was significantly higher in Jul.-Oct.than in other months.The monthly average runoff reached the maximum in Sept.,and the sediment transport rate increased significantly in Jul.and Aug.(2)The satellite-based precipitation has a higher quality than reanalysis-based precipitation.The CFSR and CDR overestimate precipitation,while the TRMM and CMADS underestimate precipitation in the Xihe River basin.The TRMM precipitation performs best during the wet season,while the CDR precipitation performed best during the dry season.After bias correction,the quality of TRMM precipitation improves significantly.(3)The results of runoff simulation show that the CFSR simulation result is significantly different from the observed runoff,and the runoff simulation results based on the OBS are the best,followed by TRMM.The simulation results of TRMM,CDR and CMADS severely underestimate the peak flood flow.The runoff simulation quality of corrected TRMM has been significantly improved,and the peak flood flow simulation is more accurate.(4)The results show that the spatial distribution of runoff erosion capacity in the study area is characterized by “Northern strong southern weak;Western strong eastern weak;And local significant”.In the upper reaches of the basin,the topographic factors are the main controlling factors of runoff erosion.With the elevation and slope increasing,the runoff erosion ability becomes stronger;In the middle reaches of the basin,the area where the vegetation coverage is low and the land use is dominated by cultivated land shows strong runoff erosion ability;In the downstream areas,the underlying surface conditions are better and the runoff erosion ability is weak;Soil factors have less impact on runoff erosion compared with terrain factors and vegetation factors. |
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