Internal layering structure and subglacial conditions along a traverse line from Zhongshan Station to Dome A,East Antarctica,revealed by ground-based radar sounding  

东南极冰盖中山站-Dome A断面的冰盖内部等时层结构与冰下环境

作　　者：Tang Xue-Yuan Sun Bo Wang Tian-Tian 唐学远;孙波;王甜甜(自然资源部国家海洋局极地科学重点实验室,中国极地研究中心,上海200136)

机构地区：[1]MNR Key Laboratory for Polar Science,Polar Research Institute of China,Shanghai 200136,China

出　　处：《Applied Geophysics》2020年第5期870-878,905,共10页应用地球物理（英文版）

基　　金：This research is supported by the Funded by the Natural Science Foundation of China(41876230,41376192);the Major National Scientifi c Research Project on Global Changes(973 Project)(2013CBA01804);Comprehensive Investigation&Assessment Programs(CHINARE2017-01-01).

摘　　要：During the 21st Chinese National Antarctic Research Expedition(CHINARE 21,2004/05),a radar dataset was collected using a ground-based radar system,along a traverse line from Zhongshan Station to DT401(130 km from the Kunlun station).The internal layering structure and subglacial conditions were revealed along the radar profi le.Continuous internal layers,disturbed layers,and echo-free zones(EFZs)along the profi le were identifi ed and classifi ed,and the spatial distribution was presented.Based on recent surface ice velocity data,we found that the internal layers at a depth of 200-300 m in the upper ice sheet are continuous,smooth,and nearly parallel to the ice surface topography.In addition,the thick band of continuous layers changes little with increasing latitude.At depths below 300 m,the geometric structure of the internal layers and the vertical width of the EFZ band are infl uenced by the surface ice velocity and bed topography.The relatively high disturbance,layer discontinuity,and larger EFZ band width directly correspond to a higher surface ice velocity and a sharper bed topography.In particular,we found that at a depth of 650-950 km,the Lambert Glacier Rift in the Gamburtsev Mountains has a higher ice fl ow;moreover,the revealed internal layers are disturbed or broken,and the maximal vertical width of the EFZ band most likely exceeds 2000 m.基于第21次中国南极科学考察(CHINARE 21,2004/05)期间获取的东南极中山站-DT401(据昆仑站130 km)冰盖断面车载冰雷达数据。首次揭示了该断面的冰盖内部等时层结构,对整个断面冰盖内部的连续层、断裂层和信号空白区(Echo Free Zones,EFZ)进行了识别和分类,给出了其空间分布。由此发现,在断面表面以下200-300 m的深度范围内,内部等时层光滑连续并近似平行于冰盖表面。在300 m以下等时层的几何结构和EFZ的宽度受到表面流速和底部地形的影响:表面流速大和底部地形变化显著的区域具有相对较大的内部等时层扰动与断裂不连续性以及较大的EFZ宽度。分析发现650-950 km甘布尔采夫山脉(Gamburtsev)边缘的兰伯特冰川(Lambert)区域是一个显著的快速冰流区,EFZ的最大垂向宽度可能超过2000 m。

关 键 词：East Antarctic ice sheet Dome A Radar Internal layers Subglacial conditions 

分 类 号：P343.6[天文地球—水文科学]