青藏高原中部那曲河流域地气水分交换过程研究

The land-atmosphere water exchange in the Tibetan Plateau has great influence on the weather and climate change in China, East Asia, and even the globe. However, our understanding on the water exchange between land and atmosphere in small watershed scale in the Tibetan Plateau is very limited. The lack of necessary quantitative understanding is especially true for the evapotranspiration, which is an important component in land-atmosphere's water exchange, and its linkage with surface layer meteorological parameters and inhomogeneous land surface characteristic parameters. Based on multi-source data, such as optical remote sensing data, microwave remote sensing data, and in-situ observation data, by using remote sensing retrieval, model simulation and statistical analyses methods, 10-year variation trends for impact factors, which influence land-atmosphere water exchange will be analyzed. Variations of evapotranspiration and precipitation, linkage mechanisms between land-atmosphere water exchange processes and their impact factors will also be revealed. Furthermore, watershed-scale quantitative methods for estimation of soil moisture and evapotranspiration will be constructed. The study will also reveal the coupling mechanisms among the watershed-scale evapotranspiration, surface layer meteorological parameters and inhomogeneous land surface characteristic parameters for different seasons, especially before and after the onset of monsoon. Therefore, a theoretical basis will be provided for large-scale land-atmosphere interactions and climate change study. It also has significant application value for local agricultural production, water resources management and drought monitoring.

青藏高原地区地气间的水分交换过程对中国、东亚乃至北半球的天气和气候变化均有重要影响，但长期以来对青藏高原小流域尺度地气间的水分交换过程认识较为匮乏，尤其是对其最重要分量之一的蒸散发及其与近地层气象参数和非均一地表特征参数之间的联系缺乏必要的定量理解。本研究拟在多源数据(光学遥感数据、微波遥感数据和地面实测资料等)的基础上，采用遥感反演、模式模拟和统计分析相结合的方法，分析那曲河流域近10年来地气间的水分交换影响因子、蒸散发与降水变化及地气间水分交换过程与内在影响因子之间的联系机制，以期建立流域尺度土壤水分和蒸散发估算的定量化方法，揭示不同季节，尤其是季风爆发前后流域蒸散发的变化及其与近地层气象参数和非均一地表特征参数之间的联系与耦合机制，从而为大尺度的陆气相互作用和气候变化研究提供一定的理论基础，而且在流域的农牧业生产、水资源的管理和干旱监测等方面具有重要的应用价值。

青藏高原地区地气间的水分交换过程对中国、东亚乃至北半球的天气和气候变化均有重要影响，但长期以来对青藏高原小流域尺度地气间的水分交换过程认识较为匮乏，尤其是对其最重要分量之一的蒸散发及其与近地层气象参数和非均一地表特征参数之间的联系缺乏必要的定量理解。本研究在多源数据(光学遥感数据、微波遥感数据和地面实测资料等)的基础上，采用遥感反演、模式模拟和统计分析相结合的方法，改进了地表反照率、植被指数、太阳辐射、大气辐射的估算方法，从过程模型角度建立了流域尺度土壤水分和蒸散发估算的定量化方法，得到那曲河流域地表特征参数、蒸散发和土壤水分状况时间序列资料。揭示了那曲河流域地气间的水分交换过程主要受限于能量因子，而与动力因子和水分因子之间的关系存在不确定性。研究成果为大尺度的陆气相互作用和气候变化研究提供一定的理论基础，而且在流域的农牧业生产、水资源的管理和干旱监测等方面具有重要的应用价值。