冰冻圈关键地区雪冰化学的时空分布及环境指示意义  

Glaciochemistry Distribution in the Surface Snow/Ice in Some Key Regions of the Cryosphere: the Environmental Significance

作　　者：效存德[1] 秦大河[1] 任贾文[1] 李忠勤[1] 王晓香[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冰芯与寒区环境重点实验室

出　　处：《冰川冻土》2002年第5期492-499,共8页Journal of Glaciology and Geocryology

基　　金：中国科学院知识创新工程项目 (KZCX2 3 0 3 ;CACX2 10 0 46;2 10 5 0 6);科技部社会公益性项目 (2 0 0 1DIA5 0 0 40 );国家自然科学基金项目 (4 99710 2 1;40 0 710 2 5 )资助

摘　　要：采用雪冰常量化学元素示踪体系 ,系统分析了冰冻圈关键地区的南极冰盖、北极格陵兰和北极中心地带、以及以青藏高原为中心的高亚洲地区现代降水 (表层雪冰 )化学的空间分布、季节变化特点 .研究表明 ,两极和高亚洲地区雪冰化学反映了全球或局地大气环境本底 :南极现代雪冰化学代表了南半球或全球本底 ,北极格陵兰地区代表了北半球对流层中部本底 ,青藏高原海拔 5 0 0 0m以上的高海拔地区雪冰化学则代表中纬度地区对流层中上部本底 .其中 ,离子浓度在两极冰盖和喜马拉雅山高海拔地区接近 ,而在青藏高原北部高海拔地区则高得多 .三个地区雪冰化学的季节分布特点是 :在南极冰盖 ,海盐气溶胶的“丰”季形成雪层化学峰值 ,在北极 ,冬春季污染物 (所谓“北极霾”)和漂尘形成季节峰值 ,在高亚洲 ,主要是春季降尘形成明显污化层 .青藏高原上大风季节与干季重叠 ,静风季节与湿季重叠 ,决定了干湿沉积过程具有明显季节转换 .总之 ,主要阴、阳离子在南、北极和高亚洲雪层中的时空分布揭示了大气气溶胶的源区和传输 ,其形成过程与大尺度大气环流、季风和局地尘暴等事件密切相关 .Large\|scaled investigation of glaciochemistry in surface snow/ice may not only provide some information on global atmospheric processes, but also lay a solid foundation for rational interpretation of regional differences of palaeo\|records in ice cores. Three key regions of the cryosphere, i.e., the Polar Regions as well as High Asia, are selected in this study for contrast study of impurities in surface snow/ice. The studied impurities include: 1) Major ions, such as Na~ +, Ca~ 2+, Mg~ 2+, Cl~ 1-, SO\+\{2-\} 4and NO 32-, 2) Halogen element Br, 3) MSA and SO\+\{2-\} 4. The sources, seasonality, spatial distribution and their environmental implications are presented. Also, the contribution percentage of various sources to some elements is estimated. Large\|scaled glaciochemical investigation reveals some information on global atmospheric processes. The major results can be summarized as follows:\;Marine aerosol is the major contributor to the glaciochemistry in Antarctic Ice Sheet. The impurities in surface snow at High Arctic may be a mixture of crustal, oceanic and anthropogenic origins. Spatial differentiation of glaciochemistry in Arctic is more complicated than those in Antarctica and High Asia. Compared with Greenland and north Canada, the Central Arctic Ocean is more influenced by the mid\|latitudinal air mass, especially in winter and early spring. Ions emitted from open waters (such as shear zones) result in concentration peaks in snow over pack ice of the central Arctic Ocean. In High Asia, continental and regional dusts play an important role in glaciochemical records, but in south margin of the Tibetan Plateau, sea salt contents increase.\;There are two major atmospheric processes that control the features of glaciochemistry in High Asia, i.e., dust storms in north and monsoon in south of the plateau, and the two processes reach equilibrium around the Tanggula Range. In High Asia the windy season coincides with dry season, and the calm season coincides with precipitation season, which lar

关 键 词：冰冻圈 时空分布 环境指示意义 南极 北极 雪冰化学 

分 类 号：P343.6[天文地球—水文科学]