基于Budyko假设的海河流域水文演变驱动机制及其区域差异性分析

In recent 50 years, the phenomenon of streamflow reduction in China has been widely concerned by government decision-making departments and the public. The research of hydrological cycle under changing environment has become a hot topic in water science research. The Budyko hypothesis is a new perspective to study the hydrological cycle process in recent years, which provides a more convenient way to explore the evolution rule and driving mechanism of hydrological processes in the basin. In this study, we take the most serious shortage of water resources of the Haihe River Basin as the study area, and aim at the scientific question of whether the catchment characteristic parameter could reflect the effects of surface characteristics changes on streamflow, to analyze the sensitivity of streamflow to precipitation, potential evapotranspiration and catchment characteristic parameter, and reveal the driving mechanism of the hydrological process change in the Haihe basin. And aiming at the scientific question of the geographical variability mechanism of hydrological evolution driving sensitivity is not clear, it is trying to be explained completely from two perspectives of climate and underlying surface. The results of this study provide a new perspective for revealing the driving mechanism of the basin's hydrological evolution, and supplement the analysis of the geographical variability on the spatial scale, which is of great significance for the study of the regional scale hydrological process mechanism.

近50年来中国河川径流量减少现象已引起政府决策部门和公众的广泛关注，而变化环境下的水文循环研究已成为当今水科学研究的热点之一。Budyko假设理论是近年来兴起的研究流域水文循环过程的一个新的视角，为探索流域水文过程演变规律及其驱动机制提供了更简便的途径。项目以水资源短缺最为严重的海河流域为研究区域，针对能否用下垫面特征参数来反映下垫面变化对流域径流的影响的科学问题，基于Budyko假设理论，通过分析流域径流对降水、潜在蒸散发及下垫面参数的敏感性系数，明确海河流域水文演变驱动机制；针对敏感性区域差异性机理不清的科学问题，从气候和下垫面两个角度来完整的解释流域水文演变驱动敏感性的区域差异性机理。项目研究结果为揭示流域水文演变驱动机制研究提供了新的视角，同时为空间尺度上的区域差异性分析进行了补充，对区域尺度流域水文过程机制研究具有重要意义。

海河流域是我国缺水最为严重的地区之一，也是我国人水矛盾最为突出的地区，系统梳理流域水文演变的驱动机制，对流域水文演变的驱动机制分析，对流域水资源管理具有重要意义。本项目以海河流域为研究区域，以区域内各子流域为研究对象，基于Budyko假设理论，分析了气候变化和下垫面变化对流域水文过程的影响量和贡献率，结果表明，海河流域变化期（1980-2000）流域径流相比基准期（1957-1979）减少45.18mm，其中气候变化的影响量为10.89mm，其贡献率为24.11%，人类活动对研究区径流变化的影响量为33.92mm，其贡献率为75.07%，海河流域径流在1957-2000年间的变化过程中，下垫面变化是主要的影响因素。与以往的研究结果类似，本研究中，我们也发现了流域水文过程对降水、潜在蒸散发以及下垫面参数的敏感性均呈现一定的区域差异性，实测数据与理论解析结果均表明，流域水文过程在越湿润的地区对气候变化越敏感，在下垫面特征值ω越小的地区对下垫面变化越敏感。最后，本研究通过将Budyko假设理论与土壤水分随机模型、TSEB模型等理论进行耦合，建立了Budyko假设理论中下垫面参数的理论公式。