Sui Ming-Zhen, Zhang Ying, Xu Qing, Gao De-Qiang, Wang Ting, Wang Si-Long
Key Laboratory of Forest Ecology and Environment of the National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.
Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Ying Yong Sheng Tai Xue Bao. 2020 Jun;31(6):1791-1799. doi: 10.13287/j.1001-9332.202006.020.
Deuterium (D) and oxygen-18 (O) are common environmental tracers in water. Understanding the isotopic compositions of precipitation is necessary for further studies on local and global water cycling processes. To reveal the mechanism of isotopic compositions of precipitation in subtropical monsoon region in response to environmental changes, we collected 49 precipitation samples and recorded related environmental factors from May 2017 to August 2019 in Huitong field station of Chinese Academy of Sciences in Hunan Province. We analyzed the temporal variations in D and O values in precipitation and analyzed the influence of water vapor source and local environmental factor on stable isotopic compositions of precipitation. The local meteoric water line was established as δD=(7.45±0.17)δO+(10.10±1.25) (R=0.93, P<0.01), the slope of which was slightly lower than China's meteoric water line and the global meteoric line. The D and O values of precipitation samples were closely coupled with local meteorological conditions and dominant moisture sources. The O and D contents were depleted during summer monsoon season but enriched during winter monsoon season. During the summer monsoon and post-monsoon seasons, precipitation in this area came mainly from the Bay of Bengal, the South China Sea, and the West Pacific at three different types of air pressure, which lead to the similarity of the D-excess value of the precipitation to global average. The lower intercept of meteoric water line and the higher D-excess value for precipitation during the winter monsoon season resulted from moisture from remote westerly air masses, degenerated tropical marine air masses from the Bay of Bengal, and inland moisture in the pre-monsoon period, which were also affected by local environmental factors.
氘（D）和氧-18（O）是水中常见的环境示踪剂。了解降水的同位素组成对于进一步研究局部和全球水循环过程至关重要。为揭示亚热带季风区降水同位素组成响应环境变化的机制，我们于2017年5月至2019年8月在中国科学院会同野外台站（位于湖南省）采集了49个降水样本，并记录了相关环境因子。我们分析了降水中D和O值的时间变化，并分析了水汽源和局部环境因子对降水稳定同位素组成的影响。当地大气降水线确定为δD =(7.45±0.17)δO+(10.10±1.25)（R = 0.93，P<0.01），其斜率略低于中国大气降水线和全球大气降水线。降水样本的D和O值与当地气象条件和主要水汽源密切相关。夏季风季节O和D含量 depleted，但冬季风季节 enriched。在夏季风和季风后季节，该地区降水主要来自孟加拉湾、南海和西太平洋三种不同气压类型的区域，这导致降水的氘过量值与全球平均值相似。冬季风季节降水的大气降水线截距较低且氘过量值较高，这是由于遥远的西风气团、来自孟加拉湾的退化热带海洋气团和季风前期的内陆水汽造成的，这些也受到局部环境因子的影响。 （注：原文中“depleted”和“enriched”未准确翻译，推测可能是“亏损”和“富集”之意，供参考，你可根据实际专业含义调整。）
