考虑融雪及土壤冻融的新安江模型及其应用——以雅砻江上游径流模拟为例
An improved Xin'anjiang model with snow melting and soil freeze-thaw processes and its application in streamflow simulations of the Upper Yalongjiang River basin
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摘要: 寒区为中国大江大河的主要产流区, 其径流预报精度直接影响下游水利工程调度和水资源科学管理。针对传统概念性水文模型较少考虑积雪融雪及土壤冻融过程对径流的叠加影响这一问题, 以新安江模型为基础, 以降水量和气温为驱动数据, 提出了基于“等效土壤温度”和“土壤冻融特征曲线”的概念性土壤冻融模块来刻画积雪融雪及土壤冻融共同影响下的流域产流过程, 构建了考虑融雪产流和土壤冻融的新安江模型。以雅砻江甘孜水文站以上流域为典型研究区, 开展了流域2017—2022年冰雪消融期逐小时的径流模拟分析。结果表明, 相比于HBV模型, 考虑融雪产流和土壤冻融的模型可以显著提升流域冰雪消融期的水文模拟精度, 各年份消融期径流的纳什效率系数中位数由0.69提升至0.83, 相关系数中位数由0.88上升至0.92。本研究所提出的考虑融雪及土壤冻融的新安江模型可以为寒区的水文业务预报提供科学支撑。Abstract: Cold areas are primary runoff generation areas of China's major rivers.The accuracy of their runoff forecasts directly affects the scheduling of downstream water conservancy projects and the water resources management.This study aims at the problem that traditional conceptual hydrological models rarely consider the combined effects of snowmelt and soil freezing and thawing processes on the runoff process.Based on the Xin'anjiang model and using precipitation and air temperature as driving data, this study proposes a conceptual soil freeze-thaw module based on the equivalent soil temperature and soil freeze-thaw characteristic curve to describe the runoff process under the joint influence of snowmelt and soil freeze-thaw, and a Xin'anjiang model considering snowmelt runoff and soil freeze-thaw is developed.Taking the watershed above the Ganzi hydrological station in the Upper Yalongjiang River basin as a typical research area to carry out the daily streamflow simulation during the snowmelt period of 2017—2022.The results show that, compared with the HBV model, the Xin'anjiang model with snowmelt runoff and soil freeze-thaw processes can significantly improve the accuracy of streamflow simulation of the Ganzi station during the snowmelt period.The median Nash efficiency coefficient increases from 0.69 to 0.83, and the median correlation coefficient increases from 0.88 to 0.92.The Xin'anjiang model improved in this study that considers snowmelt and soil freezing and thawing can provide support for hydrological forecasting in cold regions of China.