水汽来源和传输对青藏高原南部现代降水和水汽稳定同位素的影响过程研究

Moisture sources and moisture transport processes are the crucial processes to determine the regional water circulation. In this study, we monitor the evolution processes of event-based precipitation stable isotopes and water vapor stable isotopes at stations along main moisture transport paths, and analyze the large-scale TES (Tropospheric Emission Spectrometer) stable isotopes data together with the simulations from the high-resolution general circulation models. We study the evolution processes of water vapor stable isotopes and variation procesess of precipitatoin stable isotopes in different seasons when they transport from the oceans to the southern Tibetan Plateau, and quantify contributions of the long-transport moisture and local-evaporation moisture. The mechanism of fast depletion of precipitation stable isotopes in the southern Tibetan Plateau in the monsoon season are illuminated, and the influences of the interaction between the westerlies and Indian monsoon on the moisture sources and transport processes in the southern Tibetan Plateau are also explored. Finally, the evolution processes and mechanisms of the precipitation stable isotopes and water vapor stable isotopes, impacted by the westerlies and Indian monsoon, will be revealed. This study will provide the fundamental theory for the isotopic water circulation in the Tibetan Plateau beyond the interaction of the westerlies and Indian monsoon.

水汽来源和水汽传输是决定区域水循环的关键过程。本项目拟通过实施沿主要水汽传输路径的事件尺度降水稳定同位素和水汽稳定同位素变化过程实地观测、分析大空间尺度TES（Tropospheric Emission Spectrometer）反演的水汽稳定同位素卫星数据、运用高分辨率稳定同位素大气环流模型（LMDZiso）模拟等多种方法的综合分析，开展不同季节的水汽稳定同位素演变过程和降水稳定同位素变化过程研究，量化长距离传输水汽与局地蒸发水汽对当地降水稳定同位素的贡献率，阐明夏季水汽来源地的转变对藏东南降水稳定同位素快速贫化的作用机制，探讨西风和印度季风的转换对青藏高原南部降水水汽来源和传输过程的影响，揭示两大环流系统影响下的青藏高原南部降水和水汽稳定同位素的演变过程及机制，从而为西风和印度季风交互作用下的青藏高原稳定同位素水循环研究提供理论基础。

水汽来源和水汽传输是决定区域水循环的关键过程。本项目通过四年实施，开展了沿主要水汽传输路径的事件尺度降水稳定同位素和水汽稳定同位素变化过程实地观测，基本建成了印度季风降水-水汽稳定同位素观测断面；结合大空间尺度TES（Tropospheric Emission Spectrometer）反演的水汽稳定同位素卫星数据和高分辨率稳定同位素大气环流模型（LMDZiso）模拟结果，进行了综合分析，提出了印度季风传输过程中，青藏高原夏季降水稳定同位素的变化主要受控于印度北部对流活动、喜马拉雅山脉抬升作用和进入高原内部的下沉作用，进一步认识了El Niño-Southern Oscillation（ENSO）影响青藏高原季风降水稳定同位素变化的机制，初步探讨了西风-季风转换对过去一百年青藏高原冰芯稳定同位素的影响，为西风和印度季风交互作用下的青藏高原稳定同位素水循环研究提供了新的理论依据。本项目基本完成了项目制定的研究内容和研究目标，发表了4篇国际高水平期刊论文，完成了1名博士研究生和1名硕士研究生的培养。