黄河中游窟野河流域“蓝水-绿水”转化及其对植被变化的响应

Vegetation change is one of the main drivers of changes in hydrological processes. Vegetation in the middle Yellow River has been greatly restored because of the significant progress of soil and water conservation during the past decades, which would have impacts on the water cycle. In the middle Yellow River, as a semi-arid and semi-humid region, more than 80% of precipitation is consumed as the form of "green water" (soil moisture and evapotranspiration), while past studies on vegetation change impacts mainly focus on the "blue water" (runoff). In this study, we intend to analyze the changes in vegetation，"blue water" and "green water" in the Kuye River Basin during the past 30 years, and investigate the feedback mechanism of "blue water-green water" conversion to vegetation change. We focus on the spatial and temporal changes in evapotranspiration under the impacts of changes in soil moisture because of changes in vegetation cover. Moreover, a distributed hydrological model which can reflect the impact of vegetation change on water cycle will be developed to simulate the conversion process between "blue water" and "green water". In addition, trends in runoff, soil moisture and evapotranspiration in the future will be projected based on different scenarios of vegetation restoration. The results could be helpful to the research of human impacts on hydrology and water resources, and also provide reference for the water resource management in the Yellow River Basin.

植被变化是流域水文过程变化的重要驱动因素。随着黄河中游水土保持工作的重大进展，黄河中游植被得到极大的恢复，植被恢复必然会影响水循环过程。作为半干旱半湿润区，黄河中游80%以上的降水以“绿水”形式（蒸散发和土壤水）输出，而以往的植被变化影响主要集中在“蓝水”（径流）研究。本项目以黄河中游植被变化显著的窟野河流域为研究对象，系统分析近30年来窟野河流域植被演变格局和“蓝水”、“绿水”变化特征，探索 “降水-蓝水-绿水” 转化过程对植被变化的响应机理，重点揭示植被变化通过影响土壤水的时空分布进而影响蒸散发的时空变化，最终导致径流的变化。在此基础上构建反映植被变化影响的分布式水文模型，模拟“降水-蓝水-绿水” 动态转化过程；基于未来可能的植被恢复情景，预估流域内径流、土壤水和蒸散发等相应的变化趋势。研究结果对评价人类活动对流域水文水资源的影响具有科学意义，并可为黄河流域水资源管理提供参考。

植被变化是流域水文过程变化的重要驱动因素。随着黄河中游水土保持工作的重大进展，黄河中游植被得到极大的恢复，植被恢复必然会影响水循环过程。项目主要研究内容为：以黄河中游植被变化显著的窟野河流域为研究对象，将遥感解译和水文模拟相结合，开展“降水-蓝水-绿水”转化对植被变化的响应研究，预估植被恢复情景下“绿水”与“蓝水”的变化趋势，为黄河流域水资源管理提供科学参考。项目组针对研究目标，取得了以下成果：1）揭示了研究区蓝水、绿水时空分布格局及其循环转化机制，探明蓝水、绿水与植被变化间的驱动与响应关系；2）构建了能反应植被变化影响的“降水-蓝水-绿水” 动态转化模拟模型，为黄河中游水资源模拟与管理提供工具；3）基于水文模型，估算了植被对“降水-蓝水-绿水”动态转化过程的影响，预估了未来植被恢复情景下降水转化为“蓝水”与“绿水”的变化情景，为黄河流域水资源配置和生态建设提供参考。项目执行期间，发表论文14篇，其中SCI论文11篇，包括专业1区/TOP论文8篇，中文核心论文3篇。1篇论文入选ESI前1%高被引论文。项目主持人在项目执行期获国家自然科学基金优秀青年基金的资助，项目参与人员入选中国科学院青年创新促进会。