地理学报 ›› 2008, Vol. 63 ›› Issue (1): 12-22.doi: 10.11821/xb200801002

• 土地利用 • 上一篇    下一篇

西北地区大气降水δ18O 的特征及水汽来源

柳鉴容1,2, 宋献方1, 袁国富3, 孙晓敏3, 刘鑫1,2, 陈锋2,4, 王志民1, 王仕琴1,2   

  1. 1. 中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室, 北京100101;
    2. 中国科学院研究生院, 北京100049;
    3. 中国生态系统研究网络水分分中心, 北京100101;
    4. 中国科学院大气物理研究所, 北京100029
  • 收稿日期:2007-08-28 修回日期:2007-11-25 出版日期:2008-01-25 发布日期:2008-01-25
  • 作者简介:柳鉴容(1982-), 女, 辽宁沈阳人, 中国地理学会会员,硕士研究生, 主要研究方向为流域水循环。 E-mail: liujr.05s@igsnrr.ac.cn
  • 基金资助:

    国家自然科学基金项目(40671034); 中国科学院资源环境领域野外台站研究基金项目“中国生态系统研究网 络大气降水环境同位素研究项目”

Characteristics of δ18O in Precipitation over Northwest China and Its Water Vapor Sources

LIU Jianrong1,2, SONG Xianfang1, YUAN Guofu3, SUN Xiaomin3, LIU Xin1,2, CHEN Feng2,4, WANG Zhimin1, WANG Shiqin1,2   

  1. 1. Key Laboratory of Water Cycle & Related Surface Process, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2. Graduate University of the Chinese Academy of Sciences, Beijing 100039, China;
    3. CERN Sub-center of Water, Beijing 100101, China;
    4. Institute of Atmospheric Physics, CAS, Beijing 100029, China
  • Received:2007-08-28 Revised:2007-11-25 Published:2008-01-25 Online:2008-01-25
  • Supported by:

    National Natural Science Foundation of China, No.40671034; Foundation for Environment Field Stations Research of CAS, Program for Isotopes in Precipitation of Chinese Ecosystem Research Network

摘要:

根据2005 年各月在中国大气降水同位素观测网(CHNIP) 位于西北地区的阜康、策勒、 临泽、海北、沙坡头、长武和安塞观测站点收集的降水样品, 对其中的同位素的组分进行测 定, 分析了西北地区大气降水中δ18O的时空分布特征。所建立的局地大气降水线方程"D = 7.05δ18O- 2.17, 反应了西北地区独特的局地气候特点。降水δ18O的温度效应显著, 而降水量 效应只在夏季(6-8 月) 间存在。δ18O的空间分布特征可以很好地反映西北地区的大气环流背 景。应用瑞利分馏模型及动力分馏模型对阜康- 安塞沿线降水δ18O 的定量模拟结果, 揭示了 西北地区降水水汽的分馏主要以动力分馏为主, 雨滴在降落过程中历经了一定的二次蒸发过 程, 其降水水汽中也混入一定量的由局地再蒸发的水汽。此外, 利用西北地区在全球大气降 水同位素观测网络(GNIP) 中的乌鲁木齐、和田、张掖、兰州、银川和西安6 个站点的长时 间序列的δ18O与降水量、温度等气候因子建立的多元线性回归关系可以对降水δ18O进行定量 估算; 基于乌鲁木齐站点12 年的δ18O资料对该地区的温度拟合, 为历史气候的定量恢复提供 了依据。

关键词: 西北地区, δ18O, 大气降水, 水汽来源

Abstract:

In order to reveal the characteristics and climatic controls on the stable isotope composition in precipitation over Northwest China, seven stations have been selected from the Chinese Network of Isotopes in Precipitation (CHNIP). During the year 2005, monthly precipitation samples have been collected and analyzed for the composition of δ18O . The established local meteoric water line "D = 7.05δ18O - 2.17, based on the 50 monthly samples obtained, could be treated as isotope input functions across the region. The deviations of the slope and the intercept from the Global Meteoric Water Line indicated the specific regional meteorological conditions over Northwest China. The monthly δ18O values were characterized by a strong correlation with the surface air temperature and a weak correlation with precipitation amount. However, if only the % values during summer period have been taken into account, the amount effect visualized. Spatial distributions of δ18O have properly portrayed the atmospheric circulation background in each month over Northwest China. The quantitative simulation of δ18O, which involved a Rayleigh fractionation model and a kinetic fractional model, demonstrated that the kinetic fractionation was the dominating function of condensation of raindrops. Furthermore, the raindrops suffered re-evaporation during the falling process, and the precipitation vapor has been mixed with a quantity of local recycled water vapor. A multiple linear regression equation and a δ18O-T relation were gained by using meteorological parameters to evaluate physical controls on the long-term values. The established δ18O-T relation, which has been based on the present-day precipitation, was the first step of quantitatively reconstructing the paleo-climate.

Key words: Northwest China, δ18O, precipitation, water vapour source