Simulation Of Soil Conservation Service Of The Jinghe River Basin Under The Background Of Climate Change

The Loess Plateau is one of the regions with the most severe soil erosion in China and even in the world.In the context of global climate change,how to change ecosystem services is an important scientific issue.Ecosystem soil conservation service is the main way to curb soil erosion.Exploring and predicting the temporal and spatial changes of soil conservation services of important watersheds in the Loess Plateau can provide a theoretical basis for the ecological construction of the Loess Plateau.There are currently few relevant studies.This study selects the Jinghe River Basin in the Loess Plateau as the study area.This study uses the regional climate model WRF model to obtain daily high-resolution(0.05°×0.05°)meteorological driving data to explore the law of climate change in the basin.Constructing SWAT model,and using the meteorological module as interface to link down-scaled meteorological data to the SWAT model to simulate the hydrological process of the basin from 2021 to 2035 and analyze the differences Temporal and spatial change characteristics of ecosystem soil conservation services under climate scenarios.Finally,starting from the purpose of enhancing soil conservation services,it provides countermeasures for the ecological environment construction of the basin for how to adapt to future climate changes.The main research results are as follows:(1)The WRF model has strong ability to simulate temperature and precipitation in the Jinghe River Basin.On the time scale,the R2 of the multi-year monthly average of the daily maximum temperature,minimum temperature,and precipitation and the measured value are 0.95,0.94 and 0.80,respectively,and the NSE are 0.8,0.94 and 0.59,respectively.On the spatial scale,the PCC of the simulated and measured results are 0.81,0.85 and 0.80,respectively.The downscaling model established based on the combination of optimized parameterization schemes can more accurately reflect the magnitude,temporal fluctuation and spatial distribution laws of temperature and precipitation elements,and the simulation results are reasonable and reliable.(2)The regional climate of the Jinghe River Basin is developing in the direction of"warming and wetness",and the instability of the climate system is increasing.On the one hand,the maximum and minimum temperatures in the basin are rising,and the warming rate will accelerate in the future.On the other hand,the precipitation in the basin fluctuated and increased.Compared with 2000-2020,the growth rate will slow down in the future period under the RCP4.5 scenario,while accelerate under the RCP8.5 scenario.In terms of multi-year average precipitation:RCP8.5>RCP4.5>2000-2020.Finally,the inter-annual fluctuations of future meteorological elements will increase,especially the standard deviation of annual precipitation will increase from 81.73mm to 136.67mm and 132.35mm under RCP4.5 and RCP8.5 scenarios,which exacerbate the instability of the climate system.(3)The amount of soil conservation in the Jinghe River Basin varies greatly from year to year.First of all,the amount of soil conservation in the historical period showed a fluctuating increasing trend,the growth rate is 5.29×106t/a,and the multi-year average soil conservation is 4.21×108t.Secondly,the overall amount of soil conservation under the two climate scenarios is higher than that in the historical period.The multi-year average soil conservation under the RCP4.5 scenario is 9.79×108t,and under the RCP8.5 scenario is 10.98×108t.Finally,the inter-annual variation of soil conservation is greatly affected by precipitation.The correlation coefficients of annual soil conservation and annual precipitation under the 2000-2020,RCP4.5 and RCP8.5 scenarios are 0.82,0.80 and 0.81,respectively.The amount of soil conservation is high in years with heavy rainfall.(4)The historical and future spatial patterns of soil conservation intensity in the Jinghe River Basin are consistent,and there are obvious differences within the region:the overall performance is low soil conservation intensity in the northern loess hilly area and central loess plateau area(less than 30t/ha),and high soil conservation intensity in Liupanshan in the southwest and Ziwuling in the southeast(greater than 50t/ha).