表层雪中稳定同位素季节变化及其与水汽输送的关系——以天山乌鲁木齐河源1号冰川积累区为例  

Seasonal variations of stable oxygen isotope in surface snow and vapor transportation at the headwaters of Urumqi River,Tianshan Mountains

作　　者：李亚举[1] 张明军[1,2] 李忠勤[1,2] 王圣杰[1] 王飞腾[2] 

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070 [2]中国科学院寒区旱区环境与工程研究所冰冻圈科学国家重点实验室/天山冰川观测试验站,兰州730000

出　　处：《地理研究》2011年第5期953-962,共10页Geographical Research

基　　金：教育部新世纪优秀人才支持计划项目(NCET-10-0019);国家自然科学基金项目(40701035;40631001;40571033;40701034;J0630966);陇原青年创新人才扶持计划项目;国家重点基础研究发展规划(973)项目(2010CB951003;2007CB411501);中国科学院知识创新工程重要方向项目(KZCX2-YW-127);冰冻圈科学国家重点实验室自主研究项目资助

摘　　要：根据2002年9月至2005年12月在天山乌鲁木齐河源1号冰川积累区采集的表层雪样品,揭示了该区表层雪中δ18O值的季节变化特征,讨论了水汽输送对降水中δ18O值变化的影响。研究表明,天山乌鲁木齐河源1号冰川表层雪中δ18O值季节变化显著,变幅可达12.59‰左右,其变化趋势和气温的变化趋势基本一致,二者存在显著的正相关关系,即温度效应;但后沉积作用使干季和湿季温度效应表现出不同特点。根据水汽追踪结果,该地区干季水汽来源主要与西风环流控制的水汽输送有密切关系;湿季则受内陆和局地水汽影响强烈。水汽输送的距离远近和性质对该地区降水中δ18O值变化都有一定的影响。Discussion on δ18O values in 40 samples of surface snow collected from September 2002 to December 2005 on the east branch of Glacier No.1 at the headwaters of Urumqi River,eastern Tianshan Mountains（43°06′N,86°49′E,4130 m a.s.l.） is presented.Seasonality of δ18O values in surface snow is analyzed,as well as the effects of different moisture transportation on δ18O values in atmospheric precipitation.The research result indicates that a significant seasonal variation of δ18O values is found in surface snow,which is similar to air temperature in tendency;δ18O values in wet season is generally above that in dry season,with the range of 12.59‰.There is a positive correlation between air temperature and δ18O values.However,many factors may contribute to the variation of δ18O values during post-depositional process（e.g.snow drifting,seasonal snow melt water,surface snow refreezing and mass-exchange between snow and atmosphere）,and alter the significant relationship between air temperature and δ18O values in surface snow.And the coefficient is high in wet season（0.76） and low in dry season（0.57）.Different transmission source of moisture is another main factor affecting the seasonal variation of δ18O values in precipitation.Transportation distance and characteristic of vapor have a certain influence on variation of δ18O values in precipitation.Based on the HYSPLIT air trajectory model,vapor source in dry season is closely related to water transmission controlled by Westerlies,while that in wet season is strongly influenced by regional and local air mass.And at the junction for different seasons,both the two sources have effect on this area.

关 键 词：氧同位素 表层雪 后沉积作用 水汽输送 天山 

分 类 号：P343.6[天文地球—水文科学]