关键词: 内陆河山区流域, 出山径流, 分布式径流模型, 全球变化, 植被

Abstract: Distributed hydrological model has been studied worldwide, while rarely used in large basin scale for the required huge data. In order to predict the future runoff under global warming, and to approach the effects of vegetation on the ecological environment of the inland river mountainous watershed of Northwest China, where has glacier, desert, forests, pasture, little population and little hydrometric stations, the authors use the routine hydrometric data to create a distributed monthly and a daily model with some conceptual parameters, coupled with GIS and RS tools 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. The data used in the model are precipitation, air temperature, runoff data, soil weight water content, soil depth, soil bulk density, soil porosity, land cover data etc. The model holds that if the water amount is more than the water content capacity, there will be surface runoff. The actual evaporation is proportional to the product of the potential evaporation and soil volume water content. The studied basin is Heihe mainstream mountainous basin, with a drainage area10 009 km². The data used in monthly model are observed in the period of Jan.1980 to Dec.1995, and the first 10 years data are used to simulate, while the last 5 years data are used to calibrate. For the simulation process, the NSE(Nash-Sutcliffe Equation), B(Balance Error) and EV(Explained Variance) is 0.868 1, 5.400 8 and 0.871 8 respectively, while for the calibration process, is 0.879 9, -0.597 4 and 0.880 0 respectively. The monthly model results show that, the future runoff of Heihe river basin will increase a little. The snowmelt, glacier meltwater and the evapotranspiration will increase. The air temperature increment will make the permanent snow and glacier area diminish, and the snowline will rise. The vegetation, especially the forest in Heihe mountainous watershed, could adjust the runoff process, and could increase the soil water content. For the randomness of the daily precipitation, the daily model results are not well when using the daily data in the year 2002.

Key words: inland river mountainous basin, runoff from mountainous basin, distributed runoff model, global warming, vegetation