乌鲁木齐河源1号冰川雪坑δ^18O剖面特征与气候的关系  

Relationship between Profile Features of δ^(18)O in Snow Pits over a Mountain Glacier and Local Climate——A Case Study on Glacier No.1 at the Headwaters of the Urumqi River in the Tianshan Mountains

作　　者：李亚举[1] 张明军[1,2] 李忠勤[2,1] 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,甘肃兰州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,甘肃兰州730000

出　　处：《干旱区研究》2011年第6期950-956,共7页Arid Zone Research

基　　金：国家自然科学基金项目(41161012,40701035,40631001,40571033,40701034);教育部新世纪优秀人才支持计划项目(NCET-10-0019);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;西北师范大学知识与科技创新工程创新团队项目(NWNU-KJCXGC-03-66);科研骨干培育项目(NWNU-KJCXGC-03-78)

摘　　要：2004年10月至2005年9月,在天山乌鲁木齐河源1号冰川积累区采集了16组雪坑样品。利用雪坑中δ18O资料,分析干季和湿季冰川雪坑δ18O剖面特征与气候的关系。结果表明:δ18 O变化主要集中在雪坑上部,在距底部附加冰130 cm以下变化不大,且维持在较高值。其中,干季雪层剖面上部基本反映了积累期温度的变化,湿季不同雪层之间的同位素差异变小,峰值削弱,反映了同位素分馏在干湿季的不同作用,体现了同位素后沉积作用的富集与均质化效应的季节差异。During the period from October 2004 to September 2005,snow samples were collected from 16 snow pits at the accumulation zone of Glacier No.1 at the headwaters of the Urumqi River in east Tianshan Mountains.According to the δ18O data of the snow samples,the relationship between δ18O in the snow pits over the glacier in different seasons and local climate was discussed.The result indicated that an evident profile characteristic was displayed in different periods（dry season or wet season）.In general,a significant variation occurred at the upper snow pits,and a high value was steadily maintained at the bottom（within 130 cm to superimposed ice layer）.A snow stratigraphy was a record of temperature variation during accumulation period in dry season;in wet season,however,variation range of δ18O was reduced,and the peak was dropped down.In dry season,isotope value was mainly affected by partial melting and refreezing process of surface snow,snow/firn texture transformation and exchange of atmospheric moisture,but most information of δ18O variation in snow pits was kept.In wet season,distribution of δ18O in snow pits was strongly affected by enrichment of melt water infiltration and homogenizing process,some typical values（e.g.peaks） were smoothed;so from the top to the button,the δ18O value was homogenized more and more significantly.In conclusion,the δ18O value in the snowpack at the accumulation zone of Glacier No.1 at the headwaters of the Urumqi River reflects mainly the local temperature variation in dry season,but it was significantly affected by fractionation and homogenizing process.Due to the complex process of fractionation in wet season and the limited time density,a further investigation will be needed in the future,especially for the improvement in the sampling spatiotemporal interval and quantification of explanations.

关 键 词：冰川雪坑 氧同位素 干季 湿季 气候 1号冰川 乌鲁木齐河 

分 类 号：P343.6[天文地球—水文科学]