北极生长的多年海冰晶体结构分析  

Crystals and Fabrics of an Arctic Multi-Year Ice Sample

作　　者：李志军[1] 康建成 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024 [2]中国极地研究所,上海200129

出　　处：《冰川冻土》2001年第4期383-388,共6页Journal of Glaciology and Geocryology

基　　金：中国首次北极科学考察资助项目;国家自然科学基金项目 ( 4 9776 2 78);人事部非教委系统回国留学人员基金资助

摘　　要：对中国首次北极科学考察钻取的一根从表面到底面长 2 .2m的海冰冰芯样 ,依据冰芯样采取时造成的长度 ,不等间距地自上而下垂直切片 ,剖析了冰芯样的晶体结构 ,获得以纯热力学生长为主的多年海冰正交偏光镜下晶体结构剖面 .由晶体结构剖面确定出该海冰为三年冰 ,此外 ,还发现北极海冰越夏过程中生成一种动力碎屑凝聚冰 .除给出偏光镜下晶体结构剖面和冰芯层理分析外 。One of sea ice core samples taken from Arctic by the First Chinese National Arctic Research Expedition in 1999 was cut from top to bottom for ice crystal and fabric analysis. The core was located at 72°24.037′N, 153°33.994′W and 2.2 m in length. After detail description on the ice sample fabric under light, 20 vertical sections and 2 level sections were cut from the core. These ice sections covered the ice sheet from surface to bottom, with some loses during sampling and section cutting. The structure and crystals along the depth of the core were observed and analyzed. A kind of hydrodynamic effect on ice crystals was found and was defined as refrozen clastic pieces. The air bubbles in these refrozen clastic pieces have ball shape with 1 mm in diameter, uniform distribution and about 4% in volume. The air bubbles in the columnar S 2 ice are about 15% by volume and has strip parallel to the crystal long axis. The air bubbles in grain crystal are about 15-30%, with ball shape and 1 to 3 mm in diameter. Ice crystals from surface to bottom of the sample are columnar, refrozen clastic pieces, grain, columnar, refrozen clastic pieces, grain, columnar and refrozen clastic pieces, respectively. Usually, columnar crystal is 10 mm in size, grain crystal is 2.6 mm in size and refrozen clastic piece is less than 1mm in size with columnar ice blocks and refrozen water. From surface to the depth of 95 cm, thin different color crystals enclosed by main crystals. These indicate that the sample was three year old, and the ice surface has been melted and meltwater has immigrated into the ice sheet during summer. Hence, the annual energy balance in the Arctic can be determined as ice surface melting in summer and bottom growing in winter. Ice sheet thickness kept in a constant at a certain position based on the climate and ocean condition. As this point, the three year ice covered the period from 1997 winter to 1999 summer. This division is reasonable to explain the ice crystals, especially the refrozen clastic pieces. The

关 键 词：海冰 晶体结构 北极 冰芯 成冰机制 偏光镜 晶体 

分 类 号：P731.15[天文地球—海洋科学]