西双版纳台风期降雨δ2H和δ18O特征及控制因素

Characteristics and Controlling Factors of δ2H and δ18O in Typhoon Precipitation in the Xishuangbanna Region

  • 摘要: 全球气候变化背景下极端降雨事件频发,台风作为极端降雨事件的重要贡献来源对区域环境与社会经济具有重要影响。西双版纳位于云南省最南端热带地区且是西行台风的终端影响区,研究该区域降雨δ2H和δ18O可为解析台风在我国热带的水汽输送路径及控制机制提供科学依据。本研究测定2021—2024年西双版纳多场台风前、中、后期降雨样品,结合HYSPLIT后向轨迹模型及气象数据,分析了降雨δ2H和δ18O时间变化特征及主控因子。结果表明:台风期降雨δ2H和δ18O具有明显的三阶段变化规律,并具有独特的延迟贫化特征,该贫化过程常发生在台风结束后1~3 d。降雨δ2H和δ18O贫化幅度主要与台风强度和台风低压中心与研究区的距离有关。降雨δ2H/δ18O与局地气象因子相关性随台风强度升高呈明显的减弱趋势,超强台风期间局地气象因子的影响完全被掩盖。本研究填补了西双版台风期降雨δ2H和δ18O研究空白,对理解台风对内陆水循环过程扰动及优化区域水资源管理具有启示意义。

     

    Abstract: Extreme rainfall events occur frequently under the background of global climate changes. As an important contributor to extreme rainfall, typhoons exert significant impacts on regional environment and social economy. Xishuangbanna, located in the southernmost tropical region of Yunnan province, serves as the terminal affected area of westward-moving typhoons. Investigating precipitation δ2H and δ18O in this region can provide a scientific basis for deciphering the water vapor transport pathway and controlling mechanism of typhoons in tropical China. In this study, rainfall samples were collected before, during, and after multiple typhoon events in Xishuangbanna from 2021 to 2024. Combined with the HYSPLIT backward trajectory model and meteorological data, the temporal variations and dominant controlling factors of δ2H and δ18O in precipitation were analyzed. The results show that the δ2H and δ18O in typhoon-related rainfall exhibited a distinct three-stage variation pattern with a unique delayed depletion feature, which usually occured 1-3 days after the typhoon. The depletion magnitude of δ2H and δ18O in rainfall was mainly controlled by typhoon intensity and the distance between the typhoon low-pressure center and the study region. The correlations between precipitation isotopes and local meteorological factors were more weak with the increasing typhoon intensity, and the influences of local meteorological factors were completely masked during the super typhoons. This study filled the research gap of δ2H and δ18O in typhoon-related rainfall in Xishuangbanna, and provided implications for understanding the disturbance of typhoons on inland water cycle processes and optimizing regional water resource management.

     

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