Runoff Simulation Of Xilin River Driven By Multi-source Data And Impact Of Land Cover Change On Runoff

Xilin Gol Grassland is the most representative area of the typical grassland in the north of China,and it is a green screen for wind and sand fixation in northern China.As the source of Xilin Gol grassland life,the Xilin River has severe climatic conditions and extremely fragile ecological systems.Strengthening the protection of water resources and ecological environment has become a hot issue in society and scientific research.To solve the problem of eco-environmental problems and the sustainable development of resources such as water and vegetation in typical grassland basins in Inner Mongolia,we should cut in from the perspective of basin scales,explore the driving mechanism of water resources systems,and analyze the impact of changing conditions on the underlying surface of the basin.This article takes the Xilin River Basin as the research object,investigates and studies the soil and land use in the area,and obtains the Xilin River runoff data,as well as local economic development and other indicators.Using the SWAT distributed hydrological model,runoff simulation of the Xilin River was conducted to analyze the evolution mechanism of the water cycle in the basin.At the same time,the reanalysis data CFSR and the China Assimilation Data Set CMADS were analyzed and evaluated by statistics and collaborative kriging in Xilin.The applicability of the river basin;through the SWAT model,the use of extreme land use methods to study the effects of land use/climate change on runoff in the basin,providing a feasible basis for the rational development of water resources in the basin and the governance of the ecological environment.The results of the study are as follows:?1?SWAT database of the study area was constructed based on data from DEM,soil,land use,and hydro-meteorology in the Xilin River Basin.Xilin River Basin was subjected to runoff simulation for nearly 35 years from 1979 to 2013,and annual and monthly runoff simulation results for the Xilin River were obtained.The annual simulation results evaluation indicators E_ns,R²,and R_e were 0.72⁰.75,0.75⁰.76 and6%¹9%,respectively;the monthly simulation results of E_ns,R²,and R_e were0.69⁰.7,0.7⁰.71,and 19%²1%,respectively.The simulated runoff curve and the actual runoff curve are basically the same,and the simulation results are satisfactory,indicating the applicability of the SWAT model to runoff simulation in arid and semiarid grasslands.?2?Using statistical and co-kriging interpolation to compare the main meteorological parameters of the re-analysis data CFSR and the assimilation data CMADS with rainfall and temperature,it is concluded that the CFSR data set rainfall and annual average temperature are significantly higher than the actual observations.However,the overall trend of change is more consistent;the CMADS dataset has a higher degree of fit to the curve of rainfall,annual mean air temperature,and actual observed values.?3?The CFSR data set is modified with a correction factor of 0.68,and the modified CFSR data and CMADS data are processed to construct a database,and the SWAT model is driven to establish CFSR-SWAT mode and CMADS-SWAT mode for runoff simulation.In the CFSR-SWAT model,the runoff simulation results are only satisfactory.E_ns,R²,and R_e are 0.60,0.69,and 24%,respectively.The trend of the simulated runoff curve was consistent with the actual runoff curve,but the flood peak flow was overestimated,resulting in the annual runoff.Traffic is higher than measured.The annual runoff simulation results under the CMADS-SWAT model are very satisfactory.E_ns,R²,and Re are 0.92,0.91,and 17%,respectively.Simulated runoff curves and actual runoff curves have a high degree of fit,and CMADS data drive performance in the Xilin River Basin.Better,applicability is better.?4?Based on the extreme land use law,four types of land use scenarios were established to analyze the characteristics of runoff changes under different land use conditions.The results showed that the increase in forest land and high-covered grassland area,and the reduction of sand and dry land reduced the total annual runoff of the basin;when the area of land types such as sandy land and dry land increased,the annual runoff volume increased.Through the study of runoff in each month under different scenarios,it is shown that changes in land use have a greater impact on the rainy season during the flood season in the basin than in other months.