黄土高原流域尺度植被-水分-能量耦合平衡机制及时空动态演变研究

Large-scale vegetation restoration and reconstruction of the Loess Plateau have greatly changed the balance relationship between water and energy as well as ecological environment. However, the dynamic behavior of these progress have not been well acknowledged, which caused concern about ecological restoration and water resources sustainable utilization. This project focus on fourteen major catchments of the Loess Plateau. Based on remote sensing monitoring, hydrometeorological observations and field investigation, the artificial and natural vegetation will be distinguished at the eco-hydrological unit level by applying a machine learning algorithm. Following that, we attempt to establish a dynamic relationship of vegetation type and status with environmental factors, and further develop an eco-hydrological models of watershed scale coupling with dynamic vegetation. Through the high precision description of the dynamic balance process about vegetation-water-energy, the function mechanism of vegetation on water, energy as well as the water-energy balance will be illuminated, and the spatial-temporal dynamic effects of vegetation change on the water-energy balance will be revealed. Finally, we will explore an eco-hydrological regulation method, which can guarantee vegetation ecosystem health sustainability and water resources security. This study is not only a front exploration of watershed water-energy evolution law under the background of changing environment, but can also meet the urgent demand of the vegetation restoration optimization layout in the Loess Plateau. The result of this project will have a theoretical and practical significance to the watershed ecosystem management and social economy sustainable development.

黄土高原地区大规模植被恢复与重建已使区域的水分能量平衡关系和生态环境发生深刻变化，但其发生发展的动态过程尚未被科学认知，引发人们对区域生态恢复和水资源可持续性的担忧。本项目以黄土高原14个主要流域为研究区，集成卫星遥感、水文气象观测和野外调研等多源数据，结合机器学习分类方法，在生态水文单元尺度上对人工和自然植被进行区分；建立植被类型及状态与环境因素的动态响应关系，发展耦合植被动态的流域生态水文演化模型，通过对流域植被-水分-能量耦合动态平衡过程的高精度刻画，阐明植被对水分能量及平衡的作用机制，揭示植被变化对水分能量平衡影响的时空动态演变规律，探索保障植被生态健康可持续和水资源安全的生态-水文调控方法。本研究将既是变化环境下流域水分能量演化规律的一次前沿探索，又可满足黄土高原植被建设优化布局的紧迫需求，对流域生态系统管理和社会经济可持续发展具有重要的理论与实践意义。

黄土高原地区大规模植被恢复与重建已使区域的水分能量平衡关系和生态环境发生深刻变化，但其发生发展的动态过程尚未被科学认知，引发人们对区域生态恢复和水资源可持续性的担忧。本项目以黄土高原及其主要流域为研究区，基于实地观测调查-应用模型构建-量化评估影响-产生认知洞察的研究思路，综合应用定位监测、样带调查、遥感监测、机器学习、模型模拟等技术方法，主要围绕：植被水分能量关键数据集研制和变化特征分析、综合表达植被特征的模型构建、定量诊断水文生态要素时空变化规律以及可持续的生态-水文调控方法等方面展开，重要结果包括：研制了黄土高原长时间连续高精度土地利用/覆被、典型流域植被生态系统三维结构激光雷达和多期水分能量监测调查数据集。应用SNIC聚类算法实现植被生态水文演化单元识别，揭示了黄土高原植被与水分能量各要素及其他人文要素的相互作用模式。识别了影响水分能量平衡的流域特征要素，进而将植被-水分-能量相互影响通过数据驱动的模式嵌入到Budyko理论框架中，发展了长短期记忆网络法综合表达植被特征的时变水热耦合平衡模型。解析了区域生态系统用水和生产生活用水等水系统的时空演变特征，揭示了黄土高原主要流域水分供给与蒸发能力的变化规律，阐明了植被变化通过生物物理过程影响水分能量平衡的作用机理，发现了区域社会经济发展背景下城市化进程、产业结构调整和农业集约化是驱动植被变化引发蒸散发显著增加的新模式。提出基于水资源植被承载力表达流域植被生态健康可持续和水资源安全的生态-水文调控方法，定量揭示了黄土高原水资源的植被承载力格局、阈值和承载度，为黄土高原地区生态建设与社会经济持续协调发展提供科学依据。研发了在线可视化评估信息平台，为多用户群体的业务管理提供有力的决策支持。本研究证实了植被-水分-能量耦合是旱区高原社会-环境互馈的关键纽带，相关成果为变化环境下流域水分能量演化规律及植被建设优化布局奠定了前沿性的理论和实践基础。