慕士塔格地区大气水汽氢氧稳定同位素季节内变化特征及影响因素分析

慕士塔格地区位于青藏高原西北部,常年受西风影响。为了更清楚地认识西风水汽来源和局地蒸发过程对区域水循环过程的影响,利用2017年7月26日—2017年11月6日和2018年7月30日—2018年12月10日在慕士塔格西风带环境综合观测研究站的监测数据,分析了地表大气水汽氢氧稳定同位素组成和相关局地气象要素的变化特征及其相关关系。研究发现:慕士塔格地区水汽中δ¹⁸O、d-excess与局地温度和比湿呈现明显的小时变化、日变化和季节变化;水汽δ¹⁸O值与温度的显著正相关关系在不同时间尺度稳定存在;在小时和日尺度上,水汽δ¹⁸O值与比湿呈现对数关系;后向轨迹追踪表明,西风将西伯利亚和北大西洋及慕士塔格周围地区的水汽传输至观测站点;当水汽自地中海和北大西洋长距离传输至慕士塔格时,水汽δ¹⁸O显著降低可达约7‰,d-excess会显著增大;该地区水汽稳定同位素组成的季节变化特征与降水稳定同位素组成的季节变化特征一致。研究内容初步揭示了青藏高原西风传输水汽稳定同位素变化的主要影响因素,可为区域水循环研究提供必要...

Intra-seasonal characteristics of atmospheric water vapor stable isotopes at Muztagata and its climate controls

Atmospheric water vapor stable isotopes is an important tool to understand regional water cycle. We analyzed atmospheric water vapor stable isotopes and corresponding meteorological data at the Muztagata Station for Westerly Environment Observation and Research from July 26， 2017 to December 10， 2018. We found the significant diurnal， daily and monthly variations of atmospheric water vapor stable isotopes in this region. The δ¹⁸O is higher in summer and lower in autumn and winter. at the daily scale， the δ¹⁸O is positively related to the temperature and logarithmically related to the specific humidity， and show an inverse relationship with wind speed. Through multiple regression analysis， the results show that the effect of specific humidity on δ¹⁸O is stronger than temperature. Using the Hybrid Single-Particle Lagrangian Integrated Trajectory model （HYSPLIT）， we detected the possible moisture source during our observation and found that vapor sources and transport distance significantly impact on fluctuations of atmospheric water vapor stable isotopes. This study is helpful to better understand the temporal and spatial variations and climate controls of atmospheric water vapor stable isotopes dominated by the westerlies， and to provide the necessary data and key knowledge for regional water cycle.