概念性水文模型在出山径流预报中的应用

APPLICATION OF A CONCEPTUAL HYDROLOGICAL MODEL IN THE RUNOFF FORECAST OF A MOUNTAINOUS WATERSHED

根据HBV水文模型的基本原理 ,建立了西北干旱区内陆河出山径流概念性水文模型。该模型反映了我国西部山区流域的径流形成特征 ,将山区流域划分为高山冰雪冻土带和山区植被带两个基本海拔景观带来对山区径流的形成和汇流过程进行模拟计算 ,以常规气象站的月气温和降水量为模型的初始输入 ,模拟计算月出山径流量。应用该模型对河西走廊黑河祁连山北坡的山区流域水量平衡进行了模拟计算 ,并对年径流和逐月分配进行了预报。结果表明 ,从枯水年到丰水年 ,降水量、蒸发量、径流量和径流系数均增加 ,而冰川融水和积雪融水对出山径流的补给比重则减少 ,这表明了冰雪融水对径流的具有调节作用。黑河山区流域径流系数远比干旱内流区的平均值大 ,但要小于全国的平均径流系数。所提出的内陆河山区流域出山径流的模拟和预报模型对年径流量和月分配的预报具有较好的精度 ,可用于黑河以及其他西北干旱区内陆河出山径流的预报 ,为内陆河流域中下游的水资源分配和开发利用提供依据。

Based on the basic principle of the HBV conceptual hydrological model, a hydrological model of the mountainous watersheds in the arid inland area of northwest China was developed by the authors. This model reflects the characteristics of the runoff generation in the mountainous watersheds of west China. The model simulates the runoff formation and transformation processes of the mountainous watersheds by dividing the watersheds into two basic altitude zones, the high mountain ice and snow zone and the mountain vegetation zone. Taking the monthly air temperature and precipitation of the standard meteorological stations as the foremost inputs to the model, the monthly runoff from the mountainous watersheds is then simulated. The model is applied to simulate the water balance of a mountainous watershed of the Heihe River basin at the north flank of the Qilian mountains, and the annual runoff and its monthly distribution is then forecasted. The results indicate that, from the dry years to the wet years, all of the precipitation, evaporation, runoff and runoff coefficient increase, but the alimentation proportion of glacial meltwater and snow meltwater to the total runoff decrease. Therefore, the ice and snow meltwater plays a regulation function for the runoff. In the mountainous watershed of the Heihe River, the runoff coefficient is much larger than that of the whole arid area, but it is still less than the average value over the whole country. The model of runoff simulation and forecast for the inland mountainous watersheds applied in the present study shows rather good fitness in the forecast of the annual runoff and its monthly distribution. Therefore, the model can be used for the runoff forecast of the mountainous watersheds both of the Heihe River and other inland rivers of the arid area of northwest China. And this will serve the rational allocation, utilization and exploitation of water resources in the middle and down courses of the inland river basins.