基于改进S-W模型的南小河沟流域蒸散发分配及控制机制  

Research on the distribution and control mechanism of evapotranspiration inthe Nanxiaohegou watershed based on an improved S-W model

作　　者：杨楠 宋孝玉[2] 邓建伟[1] 李蓝君 赵新凯 孟鹏飞 符冲 魏婉茵 张育斌 丁林[1] 李浩霖 YANG Nan;SONG Xiaoyu;DENG Jianwei;LI Lanjun;ZHAO Xinkai;MENG Pengfei;FU Chong;WEI Wanyin;ZHANG Yubin;DING Lin;LI Haolin(Gansu Academy for Water Conservancy,Lanzhou 73000,Gansu,China;State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China,Xi’an University of Technology,Xi’an 710048,Shaanxi,China;Beijing University of Technology,Beijing 100124,China)

机构地区：[1]甘肃省水利科学研究院,甘肃兰州73000 [2]西安理工大学省部共建西北旱区生态水利国家重点实验室,陕西西安710048 [3]北京工业大学,北京100124

出　　处：《干旱区研究》2024年第11期1819-1830,共12页Arid Zone Research

基　　金：甘肃省重点研发计划项目(22YF7FA081);陕西省自然科学基础研究计划项目(2023-JC-ZD-30,2019JZ-45);甘肃省水利科研与技术推广计划项目(24GSLK007,23GSLK012,23GSLK013)。

摘　　要：精准量化蒸散发(ET)及组分并探明其控制因子,有利于合理评价及规划管理区域水资源。根据黄土高原水土保持治理典型小流域南小河沟流域2016—2020年连续性长期观测数据及野外试验,基于改进的S-W(Shuttleworth-Wallace)模型,模拟典型人工林地ET及组分动态变化,并利用结构方程模型(Structural Equation Modeling,SEM)分析植物蒸腾(T)、土壤蒸发(E)与控制因子间的耦合关系。结果表明:(1)改进的S-W模型在南小河沟流域适用性较好,其中土壤表面抗阻力(r_(s)^(s))的阈值为50~2500 s·m^(-1),与土壤表层含水量(θ)经验函数类型为指数型,土壤颗粒中沙粒含量越大,线型斜率越大。(2)典型人工林地ET范围为276.76~402.86 mm,多年平均T、E占ET的51.6%和48.4%,ET、T和E规律为各月间变化不明显,但日间波动剧烈,T和E波动趋势基本一致,与年降雨量变化一致,和次降雨表现滞后性。(3)SEM分析净辐射(R_(n))、气温(T_(a))、θ对ET影响最为显著,其中R_n对T影响最大(总影响为0.614),T_(a)对E影响最大(总影响为0.426);T对E体现为正相关,贡献系数达0.503。基于改进的S-W模型对ET进行评价及组分分离,为深刻揭示干旱半干旱区生态水文过程提供依据。In this study,we aimed to accurately quantify evapotranspiration(ET)and its components while exploring the factors that control it,which will facilitate the practical evaluation,planning,and management of regional water resources.Utilizing continuous long-term observation data and field tests conducted from 2016 to 2020 in the Nanxiaohegou watershed—a typical small watershed for water and soil conservation on the Loess Plateau—this study simulated the dynamic changes of ET and its components in typical plantation land using the improved Shuttleworth-Wallace(S-W)model.Additionally,we analyzed the coupling relationships between plant transpiration(T),soil evaporation(E),and control factors using a structural equation model.The results revealed the following:(1)The modified S-W model was effective for evaluating ET and its components in Nanxiaohe Valley.The threshold value of soil surface resistance(r_(s)^(s))was 50-2500 s·m^(-1),exhibiting an exponential relationship with the empirical function of soil surface water content(θ);moreover,higher sand content in the soil particles correlated with a steeper linear slope.(2)ET ranged from 276.76 mm to 402.86 mm in typical plantation land,with annual averages of T and E accounting for 51.6%and 48.4%of ET,respectively.While monthly ET,T,and E patterns were not pronounced,daily fluctuations were significant.The fluctuation trends of T and E largely reflected annual precipitation patterns but lagged behind rainfall.(3)Structural equation modeling analysis revealed that net radiation(R_(n)),temperature(T_(a)),andθexerted the most significant effects on ET,with Rn having the largest impact on T(total impact of 0.614)and T_(a) having the most significant impact on E(total impact of 0.426).T was positively correlated with E,with a contribution coefficient of 0.503.Evaluating ET and its components using an improved S-W model establishes a foundation for a deeper understanding of ecological and hydrological processes in arid and semiarid regions.

关 键 词：蒸散发组分 改进S-W模型 SEM模型 蒸发抗阻力 南小河沟流域 

分 类 号：P333.1[天文地球—水文科学]