基于SHAW模型的祁连山高寒草甸土壤水分储量及通量的模拟研究  

Simulation of soil water storage and flux of alpine meadow using SHAW model on the Qilian Mountains

作　　者：张法伟[1,2] 仪律北 郭小伟[2] 杨永胜[2] 李杰霞 曹广民[2] 李英年[1,2] ZHANG Fawei;YI Lübei;GUO Xiaowei;YANG Yongsheng;LI Jiexia;CAO Guangmin;LI Yingnian(Institute of Sanjiangyuan National Park,Chinese Academy of Sciences,Xining 810008,China;Key Laboratory of Adaptation and Evolution of Plateau Biota,Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810008,China;Forestry Carbon Sequestration Service Center,Qinghai Forestry and Grassland Bureau,Xining 810008,China)

机构地区：[1]中国科学院、三江源国家公园研究院,青海西宁810008 [2]中国科学院、西北高原生物研究所、高原生物适应与进化重点实验室,青海西宁810008 [3]青海省林业和草原局、林业碳汇服务中心,青海西宁810008

出　　处：《冰川冻土》2023年第6期1887-1896,共10页Journal of Glaciology and Geocryology

基　　金：中国科学院-青海省人民政府三江源国家公园联合研究专项(LHZX-2020-07);国家重点研发计划项目(2017YFA0604802);国家林业和草原局经济发展研究中心业务委托项目(JYFL-2021-00020);国家自然科学基金项目(41730752,41877547);青海省科技成果转化专项(2020-SF-145)资助。

摘　　要：高寒草甸是祁连山国家公园青海片区的重要植被类型之一,量化该下垫面土壤水分储量及交换过程是评估区域水源涵养功能的关键科学基础。基于2017年8月1日至2018年7月31日的祁连山南麓高寒草甸生态系统水热特征的连续观测数据,对SHAW(simultaneous heat and water)模型进行了参数优化,分析了0~100 cm土壤水分储量及通量的变化特征及环境影响。结果表明:SHAW模型可以相对准确地模拟高寒草甸土壤温、湿的季节变化特征,土壤水分的模拟效果略好于土壤温度的模拟效果。日均0~100 cm土壤水分储量(SWS0-100)为(274.99±19.57,平均值±标准差)mm,5—10月植被生长季的平均SWS0-100较非生长季低21.92 mm。SWS0-100的季节变异主要受控于群落叶面积指数的正效应和蒸散发的负效应,二者通过调控浅层(0~20 cm)和中层(20~60 cm)土壤水分储量间接影响SWS0-100。日均0~100 cm土壤水分通量(SWF0-100)为(0.16±9.52)mm·d^(-1),表现为向下传输。生长季和非生长季的SWF0-100均值分别为3.27和−3.23 mm·d^(-1)。降水和土壤温度梯度通过驱动浅层、中层土壤水分通量和深层(60~100 cm)土壤水分通量间接影响SWF0-100。研究结果可为科学评估祁连山高寒草甸水源涵养功能提供数据支撑和理论依据。Alpine meadows are one of the most important vegetation types in Qilian Mountain National Park.Quantifying soil water storage and exchange is essential to evaluating the function of regional water conserva⁃tion.Based on the continuous observational hydrothermal data from August 1,2017,to July 31,2018,and the parameterized SHAW(simultaneous heat and water)model,this paper aimed to explore the seasonal variations of 0−100 cm soil water storage and soil water flux and their environmental controls.The results showed that the SHAW model could simulate soil hydrothermal processes reasonably.The simulation performance of soil water content was better than that of soil temperature.The daily 0−100 cm soil water storage(SWS0-100)was 274.99±19.57 mm(Mean±S.D.),which was 21.92 mm lower in the growing season from May to October than that of the nongrowing season.The seasonal variations of SWS0-100 were mainly controlled negatively by evapotranspira⁃tion and positively by leaf area index,through the effects of shallow(0−20 cm)and middle(20−60 cm)soil moisture storage.The daily 0−100 cm soil water flux(SWF0-100)exhibited downward transmission and averaged 0.16±9.52 mm·d^(-1).SWF0-100 migrated downward at a rate of 3.27 mm·d^(-1) during the growing season and con⁃verged upward at a rate of-3.23 mm·d^(-1) during the nongrowing season.The seasonal variations of SWF0-100 were indirectly determined by precipitation and deep soil temperature gradients,via the effects of the shallow,middle soil water flux and the deep(60−100 cm)soil water fluxes.The research results can provide data support and a theoretical basis for the scientific evaluation of the water conservation function of alpine meadows in the Qilian Mountains.

关 键 词：高寒草甸 土壤水分储量 土壤水分通量 SHAW模型 结构方程模型 

分 类 号：P437[天文地球—大气科学及气象学]