黄河源区径流变化模拟及未来趋势预估

Runoff change simulation and future trend projection in the source area of the Yellow River

黄河源区是黄河流域的重要组成部分,其径流变化影响着整个流域的水资源和生态系统安全。本文利用1976—2014年黄河源区径流、气象、数字高程模型DEM(Digital Elevation Model)、土地利用、土壤以及第六次国际耦合模式比较计划CMIP6(6thCoupled Model Inter-comparison Project)中8个模式的3个未来情景(SSP126、SSP245和SSP585)气象数据,基于SWAT(Soil and Water Assessment Tool)水文模型,对黄河源区主要水文站的径流进行了模拟、未来预估和变化分析。研究表明:(1)SWAT模型对黄河源区历史径流模拟的适用性较好,径流模拟的不确定性较小,模拟值较接近于实测值。(2)参数敏感性分析表明27个与水文有关的参数都对径流模拟有一定的影响。其中,土壤蒸发补偿因子、湿润条件II下SCS(Soil Conservation Sevice)径流曲线数、浅层地下水径流系数的敏感性较强,径流受陆面蒸散发、下垫面和降水影响较大。(3)降水是影响未来径流的主要因素。在SSP126和SSP245两种未来情景下,吉迈、玛曲和唐乃亥3个水文站在2021—2100年的两个时期(2021—2060年和2061—2100年)年均流量均呈增加趋势;而在SSP585情景下,2021—2060年呈增加趋势,2061—2100年则呈减少趋势。相对于1976—2014年,未来近期(2021—2060年)唐乃亥和玛曲站年均流量在SSP585情景下增加幅度最低,SSP126情景下增加幅度最高;吉迈站在SSP245情景下增加幅度最高,SSP126情景下增加幅度最低;未来远期(2061—2100年)3个水文站除了吉迈站是在SSP126情景下增加幅度最低外,其余均是在SSP585情景下增加幅度最低,SSP245情景下增加幅度最高。研究结果可为黄河流域水资源管理、防洪蓄水和生态环境保护等提供科学依据与理论支撑。

The source area of the Yellow River is an important part of the Yellow River Basin,and its runoff change affects the water resources and ecosystem security of the whole basin.Using the runoff data from 1976 to 2014,meteorological data,digital elevation model(DEM),land use,soil and meteorological data of three future scenarios in eight models of the 6th coupled model intercomparison project(CMIP6)from 2021 to 2100,and based on the soil and water assessment tool(SWAT)hydrological model,this study simulated,projected,and analyzed the future runoff and variation of main hydrological stations in the source area of the Yellow River.The results show that:(1)The SWAT model has good applicability in historical runoff simulation in the source area of the Yellow River.The uncertainty of runoff simulation is small,and the simulated values are close to the measured values.(2)Parameter sensitivity analysis showed that 27 hydrological parameters have a certain impact on runoff simulation.Among them,soil evaporation compensation factor,the number of SCS(Soil Conservation Service)runoff curves under humid condition II,and shallow groundwater runoff coefficient are highly sensitive,and runoff is greatly affected by land surface evapotranspiration,underlying surface,and precipitation.(3)Precipitation is the main factor affecting future runoff.Under the two future scenarios of SSP126 and SSP245,the annual average discharge of Jimai,Maqu,and Tangnaihai hydrological stations shows an increasing trend in the two periods from 2021 to 2100,while under the SSP585 scenario,it shows an increasing trend from 2021 to 2060 and a decreasing trend from 2061 to 2100.Relative to 1976-2014,the annual average discharge at Tangnaohai and Maqu stations in the near future(2021-2060)increases the least under the SSP585 scenario and the most under the SSP126 scenario,and at Jimai station it increases the most under the SSP245 scenario and the least under the SSP126scenario.Annual average discharge at three hydrological stations in the far future(2061-2100)increases the least under the SSP585 scenario and the most under the SSP245 scenario,except for Jimai station,which has the lowest increase in the SSP126 scenario.The research results can provide important scientific basis and theoretical support for water resources management,flood control and water storage,as well as ecological environment protection in the Yellow River Basin.