Research On Distributed Hydrological Simulation And Impact Assessment Of Climate Change In Arid And Semi-arid Regions Of Northwest China

Hydrological simulation in arid and semi-arid areas has been the research focus in the field of hydrological models. Gansu Corridor, as the typical arid and semi-arid region in China, is faced with severe water problems. The developing process, principles and related research status of watershed hydrological models are introduced, and also related developments of climate change study and major research methods are introduced. Taken Shule River, Heihe River, Shiyang River, which is three big inland river basins in Hexi Corridor, as the research area, water circulation model is constructed based on distributed time-variant gain model (DTVGM), which is suitable for the Hexi Corridor. The optimizing algorithm of model parameters in DTVGM is further studied, and then impacts of climate change on the hydrological cycle in Hexi Corridor are analyzed and evaluated. The main results are as follows:(1) Problems and the status of water resources in Hexi Corridor region are analyzed, and hydrological elements of three inland river basins, which are Shule River, Heihe River, Shiyang River, are analyzed. After analyzing temperature and precipitation data of three river basins, the results show that the trend of temperature and precipitation in Hexi Corridor as a whole is increasing by fluctuations with the uneven distribution of rainfall during a year.(2) There have been good effects when applying particle swarm optimization (PSO) to optimize model parameters of DTVGM. It is shown that hydrological circulation model constructed in Hexi Corridor based on DTVGM model is suitable for arid and semi-arid region. The better simulation results have been achieved in vast majority of runoff processes of key sections of three river basins in Hexi Corridor, the efficiency coefficient of day process is above0.6, while that of monthly process is above0.7(3)Analyzing impacts of climate change on the hydrological cycle in Hexi Corridor region, the results show that there is linear relationship between runoff and precipitation of three river basins in Hexi Corridor, and the runoff goes up when precipitation increases; while the runoff fluctuates with temperature, for which the main reason is that variations of temperature have simultaneous impacts on evaporation and snow melting. The effect of evaporation and snowmelt on runoff is the opposite, that is, under different temperatures, evaporation and snowmelt are alternately dominated. The current trend of climate change is conducive to the runoff in Hexi Corridor.