瓦里关山与观风山近地面空气^7Be浓度季节性变化对比  

A comparative study on seasonal variation of ^7Be concentrations in surface air between Mt. Waliguan and Mt. Guanfeng

作　　者：万国江[1] 郑向东[2] H.N.LEE 王仕禄[1] 万恩源[1] 杨伟[1] 汤洁[2] 吴丰昌[1] 王长生[1] 黄荣贵[1] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室 [2]中国气象科学研究院 [3]Environmental Measurements Laboratory,Department of Homeland Security,NY 10014-4811,USA

出　　处：《地球化学》2006年第3期257-264,共8页Geochimica

基　　金：国家自然科学基金(40175032;40373038);美国环境测量实验室资助项目

摘　　要：7Be广泛应用于大气物质传输、表土季节性迁移和微粒混合作用的示踪。它在不同地域空气中的浓度分布构成了多领域研究的基础。7Be在对流层空气中的浓度随地表海拔高度而增加。基于瓦里关山和观风山的位置差异和海拔高差,对比观测其近地面空气7Be浓度变化不仅有益于区域尺度的大气和地表环境过程的示踪,而且对全球尺度的研究也将具重要意义。2002-10-09～2004-01-21,利用美国环境测量实验室的低水平核素表层大气采样系统在瓦里关山和观风山同步连续进行每周1个大气气溶胶样品的采集工作。7Be的比活度系用多道能谱仪进行γ谱测定,测量误差小于6%。中美两实验室对逐周样品测量结果表明两实验室的数据具有很好的可比性。两个站点7Be浓度逐周变化趋势总体相似,具有2～6周的短周期波动,波峰与波谷具有良好的对应关系,其高值或低值波动延迟或超前的差异与区域尺度的天气过程传播一致。瓦里关山和观风山7Be的年均浓度分别为(14.7±1.5)mBq/m3和(4.1±0.9)mBq/m3,前者约为后者的3.6倍。近地面空气7Be浓度与同期降水量的比较表明,在周时间尺度上,两者呈现出较好的预期负相关变化;而在月平均尺度上,两地7Be浓度变化比较稳定。位于内陆地区的瓦里关山受低海拔气团上升的影响较小,其空气中7Be浓度变化较真实地反映了中纬度、高海拔地区的背景水平。观风山地区虽然受到低纬度海洋性上升气团的影响,但7Be浓度变化仍然显示出低纬度、较高海拔地区的预期水平。^7Be, as a tracer for atmosphere transmission, seasonal transfer of surface soils and for particulate mixing, has been applied widely. Its concentration distribution in different space is an investigative groundwork in many science fields. Based on the different locations and altitude between Mt. Waliguan and Mt. Guanfeng, contrast observation of ^7Be concentrations in the surface air will be beneficial to understanding of environmental processes of atmosphere and the earth＇s surface regionally, and as well as globally. From 9 Oct., 2002 to 21 Jan., 2004, filter samples in the surface air at Mt. Waliguan and Mt. Guanfeng, China were collected once a week. Synchronous detailed γ-energy spectrometric counting of ^7Be activity by both Chinese and USA laboratories has shown that weekly variations in ^7Be concentrations were in good agreement, and that short, two-six-week fluctuating periods were found at Mt. Waliguan and Mt. Guanfeng with the annual averages of 7Be concentrations to be （14.7±1.5） mBq/m^3 and （4. 1±0.9） mBq/m^3, respectively. Based on the comparison between ^7Be concentration and rainfall in the same periods, significantly inverse relationship was found at both observation sites at a weekly scale. But ^7Be concentrations show stable at those two sites at a monthly mean scale.

关 键 词：^7Be浓度 近地面空气 季节性变化 瓦里关山 观风山 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]