冻土水热过程与分布式水文模型耦合研究

The hydro-thermal properties of frozen soil has important regulating effects on evapotranspiration, precipitation and snowmelt infiltration, soil moisture storage and migration, runoff and water routing in cold regions. In turn, it will influence the river discharge and its annual distribution. Explicitly coupling a physically based frozen soil model into a distributed hydrological model is of scientific significance in accessing the influence of frozen soil on hydrological cycles and in predicting the spatial temporal changes of hydrological processes in cold regions in the context of climate change. This study aims at developing a new cold region hydrological model through coupling a frozen soil model into a distributed hydrological model, which also will be revised for considering the hydro-thermal effects of ice layer. Based on some calibration and evaluation of the new model, the spatial-temporal patterns of soil freezing/thawing, evapotranspiration, runoff and their influencing factors will be disscused. The model will be tested with and without the frozen soil module respectively and in some scenarios to access the influences of frozen soil and other factors on hydrological processes in cold regions.

冻土特殊的水热特性对寒区土壤蒸发、降水/融雪下渗、土壤水分迁移和存蓄、产流及汇流等过程具有重要的调节作用，影响流域径流的形成及年内分配。在分布式水文模型中显式地耦合基于物理过程的冻土水热模型，在定量评价冻土及其变化对寒区水文循环的影响和分析气候变化和冻土退化背景下寒区流域水文过程的时空变化趋势等方面，具有重要的科学意义。本项目拟对国际公认的冻土水热模型进行改进，考虑地下冰层的水热效应，增强其在多年冻土区的适用性；之后与传统的分布式水文模型进行耦合，发展一个新的适合于冻土地区的寒区分布式水文模型。在对耦合模型进行验证的基础上，分析寒区流域土壤冻融、蒸散发、产流以及径流的时空分布特征，评价冻土及其变化对寒区流域水循环各要素和径流的影响。

冻土特殊的水热特性对寒区土壤蒸发、降水/融雪下渗、土壤水分迁移和存蓄、产流及汇流等过程具有重要的调节作用，影响流域径流的形成及年内分配。在分布式水文模型中显式地耦合基于物理过程的冻土水热模型，在定量评价冻土及其变化对寒区水文循环的影响和分析气候变化和冻土退化背景下寒区流域水文过程的时空变化趋势等方面，具有重要的科学意义。本项目对国际公认的冻土水热模型进行了改进，并将之与传统的分布式水文模型进行了完全耦合，发展了一个新的适合于冻土地区的寒区分布式水文模型，并在黑河流域对模型进行了验证和应用，分析寒区流域土壤冻融及其对蒸散发、产流以及径流的影响，以及他们的时空分布特征。