Simulation and component analysis of watershed runoff based on coupled snowmelt module WAS modeling
[Objective]In the context of climate change,in-depth analysis of runoff components is important for identifying runoff responses under climate change such as changes in precipitation patterns and increases in temperature.In order to improve the runoff simulation accuracy of the WAS model in highland mountainous areas,and thus to support the accurate and in-depth analy-sis of runoff components,the WAS model was developed.[Methods]Taking the upstream watershed of Maojiacun Reservoir as an example,the snowmelt module was constructed by using the degree-day factor method and the dual temperature threshold method in an integrated way,which was coupled with the WAS model,and the improved WAS model was applied to simulate and analyze the runoff and components in the watershed of Maojiacun Reservoir for the period of 2001-2020.According to the differ-ent water sources and evolution paths,the runoff is divided into three parts:baseflow,rainfall surface runoff and snowmelt sur-face runoff,and according to the different dominant factors of hydrological processes in different periods of the year,the measured runoff in different periods is used to determine the graded rates of the groundwater parameters,soil parameters and snowmelt pa-rameters,respectively.[Results]The result show that the coupled snowmelt module WAS model significantly improves the simu-lation accuracy in the spring snowmelt period compared with the original WAS model,and the improved WAS model is better than the original WAS model in the rate period and validation period with NSEs of 0.85 and 0.78,and R2s of 0.93 and 0.91,respec-tively.The runoff component analysis result showed that on the seasonal scale,baseflow,rainfall surface runoff,and snowmelt surface runoff contributed 58.1%,19.1%,and 22.8%to the spring runoff,and 30.7%,67%,and 2.3%to the summer run-off,respectively,and that there was no snowmelt surface runoff in the fall and winter runoff,and that baseflow and rainfall sur-face runoff contributed 46.4%to the fall runoff,respectively,53.6%,and 78.8%and 21.2%for winter runoff,respectively;on an annual scale,baseflow,rainfall surface runoff,and snowmelt surface runoff contributed 41.7%,53.6%,and 4.8%to total runoff,respectively.[Conclusion]The WAS model can simulate the long-term dynamic changes of runoff in general before and after the improvement,and the WAS model coupled with the snowmelt module can more accurately simulate the runoff process during the spring snowmelt period,which improves the applicability of the model in the mountainous areas of the plateau.Rainfall surface runoff is the main component of runoff in this watershed,followed by baseflow,and snowmelt surface runoff is the least.However,snowmelt plays an important role in spring runoff replenishment,and baseflow constitutes the majority of winter and spring runoff,which is important for maintaining winter and spring runoff levels.
water cycleWAS modelsnowmelt runoffrunoff simulationrunoff component analysisclimate changerainfalldynamic changes
万方数据
维普
