Spatial And Temporal Variations Of Surface Soil Moisture Content In Lhasa River Basin Based On MIKESHE

Soil moisture is an important part of the water cycle.Studying the spatial and temporal distribution of soil moisture is of great significance for preventing soil erosion and agricultural production planning.In the study of soil moisture content in areas where lack of data,due to the high cost of traditional field measurement methods,and the difficulty of obtaining high spatial resolution soil moisture content by remote sensing inversion techniques.This study uses Lhasa River basin in Tibet,as the study area.The distributed hydrological model MIKESHE is used to simulate the soil moisture content of the surface layer of 1 m,in order to obtain the spatial-temporal variation results of high-resolution soil moisture content in the basin.Using meteorological site measured data,MODIS vegetation product data,and soil data from the World Soil Database(HWSD);combined with meteorological interpolation software ANUSPLIN,soil moisture characteristic curve fitting software RETC,and spatial information processing software ARCGIS respectively for weather,soil,and vegetation data Processing,using MIKESHE distributed hydrological model to simulate the surface soil moisture content in the basin from 2008 to 2017;Analysis of spatial and temporal distribution;based on CMIP5 future scenario models(RCP4.5,RCP8.5),water and temperature data,The soil moisture content in the typical annual growing season(March-October)is predicted,and its spatial and temporal distribution characteristics are explored.In terms of spatial distribution,the surface soil moisture in the Lhasa River Basin has gradually decreased from northeast to southwest,and the soil moisture in the alpine areas of the Lhasa River is lower.The Pengbo Basin in the middle reaches of the Lhasa River,the Lhasa Valley Plain in the lower reaches,the Central Hongjikuan Valley Basin,the Nianqing Tanggula Mountains,and the Northeast Medica Wetland in the Yangbajing Basin have higher soil moisture content.In terms of time.The soil moisture is about 32%-36%from March to July,about 35%-39%in July and August.The annual change of soil moisture is more obvious than the interannual change.The difference of soil moisture under different land use types is obvious.In forest and grassland soil moisture content values are higher.The simulation results in the future show that the MRI-CGCM3 and HadGEM2-ES models have higher soil moisture content than the MPI-ESM-LR model,and the soil moisture content is increasing under the RCP8.5 emission model.The annual trend of typical soil moisture content in the future will be similar to that in 2008-2017.