地理科学进展 ›› 2012, Vol. 31 ›› Issue (11): 1452-1459.doi: 10.11820/dlkxjz.2012.11.005

• 气候与地表过程 • 上一篇    下一篇

中国西部局地蒸发水汽贡献率探讨

马潜, 张明军, 王圣杰, 汪宝龙, 马雪宁   

  1. 西北师范大学地理与环境科学学院,兰州 730070
  • 收稿日期:2012-04-01 修回日期:2012-08-01 出版日期:2012-11-25 发布日期:2012-11-25
  • 通讯作者: 张明军(1975-),男,教授,博士生导师.E-mail: mjzhang2004@163.com E-mail:mjzhang2004@163.com
  • 作者简介:马潜(1987-),男,甘肃兰州人,硕士研究生,主要研究方向为同位素地球化学.E-mail: maqian0516@126.com
  • 基金资助:

    国家自然科学基金项目(41161012);教育部新世纪优秀人才支持计划项目(NCET-10-0019);甘肃省高等学校基本科研业务费项目.

Contributions of Local Moisture to Precipitations in Western China

MA Qian, ZHANG Mingjun, WANG Shengjie, WANG Baolong, MA Xuening   

  1. College of Geography and Environment Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2012-04-01 Revised:2012-08-01 Online:2012-11-25 Published:2012-11-25

摘要: 利用降水、湖水同位素数据并结合相关模型,对我国西部地区的二次蒸发效应以及不同类型水汽对区域降水的贡献率进行了定量的讨论,研究得到以下结论:①夏季风期间,天山—阿勒泰地区所受到的二次蒸发效应较为明显;而青藏高原地区,水体蒸发水汽的向上补给则是影响该区域在全年任何时段下氢氧同位素值发生变化的主要因素.②天山—阿勒泰地区在全年任何时段下均存在二次蒸发效应,且夏季风时的作用程度明显强烈,蒸发比值介于13%~20%,均值为16.7%,远远大于冬季风时的均值4.3%.③青藏高原地区不论是在夏季风还是冬季风期间,上风向水汽对区域降水的贡献率最大,所占比重基本大于50%,贡献率最小的是水体蒸发产生的水汽,其值普遍小于10%;而蒸腾作用产生水汽的贡献率介于两者之间.

关键词: 二次蒸发效应, 局地水汽, 上风向水汽, 稳定同位素, 中国西部

Abstract: Based on stable isotope data of precipitations and lakes on the Tibetan Plateau and Tianshan-Altay areas, contributions of secondary evaporation and evaporative vapors to local precipitations are estimated. (1) The stable isotope data show that values of both δ18O and d-excess decreases from Hetian to Altay in summer monsoon (June to September), suggesting that in the area secondary evaporation has a greater effect in summer monsoon, while in Tibetan plateau area the stable isotope composition of hydrogen and oxygen increases along the water vapor trajectory in both summer monsoon and winter monsoon (October to May), contributed mainly by evaporative vapors from surface water bodies throughout the year. (2) The estimation of evaporation rate indicates that in Tianshan-Altay area the secondary evaporation happens at all times, and it has greater effect in summer monsoon, with rates from 13% to 20% and an average rate of 16.7%, and less effect in winter monsoon, with an average rate of 4.3%. (3) Using a vapor contribution rate model, contributions from moisture advection, evaporative vapors from surface water bodies, and transpiration from plants are calculated. Moisture advection generally contributes the biggest part, greater than 50%, while evaporative vapors contribute the smallest part, with an overall rate of 10%. Transpiration has a contribution rate in between.

Key words: advection moisture, local moisture, secondary evaporation, stable isotope, western China