基于水热耦合模型的镇江关流域径流驱动机制研究

Water-heat coupling model-based study on runoff driving mechanism of Zhenjiangguan Watershed

长江上游镇江关流域作为生态脆弱区,其径流驱动机制研究对于流域的发展十分关键。当前对该流域径流分析的研究多集中于水沙关系和径流时空变化分析方面,对于径流归因分析的研究不足。针对镇江关流域径流变化成因复杂的问题,为了明确河川径流变化的主导因素,基于Budyko假设建立了适用于镇江关流域的水热耦合模型。根据下垫面变化强弱划分径流序列的不同阶段,计算反映镇江关流域下垫面特征的参数ω,进而量化气候变化和下垫面变化对径流产生的影响。结果表明,1985—2015年间镇江关流域径流量呈现总体上升趋势,其中2003—2008年间气候变化、下垫面变化的贡献率分别为65.6%和34.4%;2009—2015年间气候变化、下垫面变化的贡献率分别为57.6%和42.4%,气候变化仍是影响径流变化的主导因素。研究结果有利于深入认识变化环境对流域径流变化的影响,对未来水资源系统规划设计与流域水土保持工作具有重要意义。

As an ecologically fragile area, the study on runoff driving mechanism of Zhenjiangguan Watershed in the Upper Yangtze River is quite important for the development of it. At present, most of the studies on the runoff analysis of the watershed focus on the aspects of runoff-sediment relationship and the analysis of temporal and spatial change of runoff, but the study on the attribution analysis of runoff is insufficient. Aiming at the problem that the causation of the runoff change in the watershed is complicated, a water-heat coupling model adaptable to Zhenjiangguan Watershed is established with Budyko hypothesis. In accordance with the changing intensity of the underlying surface, the different phases of the runoff series is divided, and then the parameterω reflecting the characteristics of the underlying surface of Zhenjiangguan Watershed is calculated, while the influences from climate change and the change of the underlying surface are quantified as well. The results show that the runoff in Zhenjiangguan Watershed exhibits an overall upward trend, in which the contribution rates of the climate change and the change of the underlying surface during the period of 2003—2015 are 65.6% and 34.4% respectively, while the contribution rates of the climate change and the change of the underlying surface during the period of 2009—2015 are 57.6% and 42.4% respectively, thus the climate change is still the dominant factor to influence the runoff change. The study result is favorable to deeply understand the influence from the changing environment on the watershed runoff change, and then has an important significance for the planning and design of the water resource system and the water-soil conservation therein.