植物水分利用是植物调节水分损耗、适应干旱胁迫的重要生理过程。快速准确地把握植物水分利用，是研究和理解全球升温导致的频发干旱对生态系统稳定性威胁的重要手段。植物水通量作为指征植物水分利用及其对干旱的生理响应机制的关键参数被广泛应用，但传统获取方法耗时耗力，且目前流行的基于多光谱遥感的蒸散模型则面对诸多不确定性，无法快速精确追踪植物水通量。而高光谱中包含的丰富信息为直接追踪植物水通量提供了可能。本项目将基于野外同步观测试验、控制实验和辐射传导模型理论分析，揭示植物高光谱反射信息对植物水通量的响应机制；结合实测数据和SCOPE模型，探讨利用高光谱快速准确反演植物水通量的新方法，力求建立高光谱技术研究植物水分利用变化规律的新途径，为干旱胁迫下森林生态系统水分利用状态快速诊断、生态系统脆弱性监测及适应性管理提供实时科学依据。

Increasing drought frequency and duration as well as increasing severity associating with global warming have laid great threatens on various forest ecosystems. Plant water flux is an important indicator for plant water usage reflecting the ability of plants to adjust water consumption under drought stress. A clear understanding of it is thus an essential way to improve our knowledge of plant water use under various drought stress conditions. However, traditional measurements of the indicator are generally time consuming and expensive, while current prevalent multispectral remote sensing based models are facing a number of uncertainties and yet to trace plant water use promptly. Alternatively, plenty information contained in hyperspectral remote sensing data provides a possibility to trace the indictor directly. This proposal thus targets for: 1) revealing the underlying physiological mechanisms of hyperspectra with respect to plant water flux through synchronous field monitoring and control experiments, as well as theoretical analysis using SCOPE model; and 2) exploring a new approach to trace plant water flux via hyperspectral remote sensing, including both empirical spectral index (SI) and radiation transfer model (RTM) methods. The results obtained from this study will thus lay a basis for tracing plant water use under drought stress using hyperspectral information, and will provide a practical approach for ecosystem vulnerability assessment and adaption as well.