内陆河流域分布式日出山径流模型——以黑河干流山区流域为例

应用常规的气象水文数据并结合GIS,建立了一个适合西北干旱区内陆河山区流域的以日为步长的分布式径流模型,并对黑河干流山区出山径流进行了模拟计算和讨论。模型以子流域作为最小的产流、汇流单元,根据植被覆盖将各子流域分为裸地区、乔木区、牧草区和冰川区,并根据实际调查将土壤分为 3层,各分区单独进行水量平衡计算。产流过程以土壤储水能力和储水量表征,而储水能力和储水量等则由土壤的孔隙度、干密度和厚度等表征。入渗原理基于土壤储水率平衡原理,并考虑重力势的作用。实际蒸散发与蒸发力和土壤体积含水量的乘积成正比,不同的土壤和植被具有不同的调节参数。模拟结果表明,模拟效果较差的原因是区域日降水过程具有较大的随机性,难以用有限的站点合理计算区域日降水量。寻找一个合适的区域日降水量计算方法是目前少资料大型流域分布式水文模型模拟成功的关键。

A DISTRIBUTED DAILY RUNOFF MODEL OF INLAND RIVER MOUNTAINOUS BASIN

Distributed hydrological model has been studied worldwide, while rarely used in basin scale, because it requires too many parameters and too many hydrologic data, meteorological data, soil data, vegetation data etc. The water resource is very deficient in inland river basin of Northwest China, and the runoff from mountainous basin basically represents the water resources amount of the inland arid region. In order to simulate and predict the runoff from mountainous watershed of the inland river basin, to predict the futuristic runoff under the global warming, and to answer the ecohydrologic effects of vegetations, in this paper, the author want to use the routine hydrometeorologic data to create a distributed model, coupled with GIS and RS techniques and data. The model takes sub-basin as the minimal confluent unit, divides the main soil of the basin into 3 layers, and divides the vegetation type as forest and pasture. Because there is little data required by the standard distributed model, this model gives some conceptual parameters. The data used in the model are precipitation, air temperature, runoff data, soil weight water content, soil depth, soil bulk density, soil porosity, vegetation cover etc. The model defines and introduces some concepts: soil volume water content, soil water content capacity, soil water amount, and hold that if the water amount is more than the water content capacity, there will be surface runoff. The actual evaporation is proportional tothe product of the potential evaporation and soil volume water content, and for different soil type and different vegetation type, the model give a different parameter. The studied basin is Heihe mainstream mountainous basin, with a drainage area 10 009 km², with only 8 precipitation stations, 5 air temperature and 6 evaporation stations. The model simulates the runoff variation well, while the amount is not so well. The reason is that, there are too little hydrometeorologic stations in or near the basin, while the daily precipitation varies randomly. The author use several area daily precipitation methods, however, none of which works. At present there is no suitable method to calculate the whole basin precipitation using rare station data. Therefore, one way is to add the observed stations, to create new calculation method, and to use new way to observe precipitation. It goes without saying, the model could not be used presently. However, from this numerical experiment, the modelers can get some experiences.