干旱与湿润区流域时变水热耦合参数的归因分析

Abstract

气候变化和下垫面条件的改变共同影响着流域的水热耦合状况，定量剖析其影响对研究变化环境下流域水量平衡和能量分配具有重要意义。以往多数研究只做了定性分析，对不同影响因素的定量贡献研究甚少。基于此，以干旱区无定河流域和湿润区汉江上游为研究区域，在Budyko框架下，估算了干旱与湿润区流域的时变水热耦合参数，并通过逐步多元回归模型、敏感性和贡献率分析，定量归因了水热耦合控制参数的演变，并将干旱与湿润区流域做了对比分析。结果表明：干旱与湿润区流域的水热耦合参数在1970-2013年间均呈显著上升趋势；不同气候区水热耦合参数变化的主导因子不同，干旱区无定河参数对降水和植被覆盖度（NDVI）具有较高的敏感性，且NDVI的变化主导着参数的变化（贡献率为89.5%）；湿润区汉江上游参数的变化对气温、有效灌溉面积（EIA）和NDVI更敏感，其中，EIA主导着参数的变化（贡献率为83.1%）；总体来说，下垫面的变化是无定河和汉江上游水热状况改变的驱动因素。;Under the background of global warming, the climate condition and underlying surface conditions of the Yellow River and the Yangtze River has changed significantly. Simultaneously, the intensification of human activities (e.g. urbanization, industrialization, grain for green and irrigation, etc.) has led to changes in underlying surface condition, which further changed the distribution of precipitation between evaporation, infiltration and runoff, thus affecting the hydrological cycle process. However, the change of climate change and underlying surface conditions jointly affect the watershed water-energy balance, and quantitative analysis their influence in different climatic regions is of great significance to the study of water balance and energy distribution of the basin under the changing environment. most of the previous studies only made qualitative analysis, and few studies focused on quantitative contributions. In addition, under the complex changing environment, the study of the changes of hydrological processes in different climatic regions and the influencing factors are helpful for the profound understanding of the change characteristics of hydrological processes in different climatic regions. Based on them,The Wuding River Basin in arid region and the upper Han River in humid region were selected as the study areas in the study. The time-varying Budyko parameter was estimated under the Budyko framework. In addition, the attribution of the evolution of the parameter was revealed quantitatively by the stepwise multiple regression model, sensitivity and contribution analysis. Moreover, a comparative analysis was made between the arid and humid regions. The results showed that the Budyko parameter increased significantly from 1970 to 2013 in the two selected areas with different driving factors. The dominant factors driving the variation of the parameter are different in diverse climatic regions. In the Wuding River basin, the parameter is highly sensitive to precipitation and vegetation coverage (NDVI), and the variation of the NDVI dominates its variation (the contribution rate is 89.5%). However, in the upper Han River, the variation of the parameter is more sensitive to temperature, effective irrigation area (EIA) and NDVI, and among which, the EIA dominates its variation (the contribution rate is 83.1%). In general, the change of underlying surface is the driving factor for the change of water and energy conditions in the Wuding River and the upper Han River.