The internal COF features in Dome A of Antarctica revealed by multi-polarization-plane RES  

多极化冰雷达所揭示的DOME A区域冰盖内部冰晶组构特征(英文)

作　　者：王帮兵[1] 田钢[1] 崔祥斌[1] 张向培[2] 

机构地区：[1]浙江大学理学院地球科学系,浙江杭州310027 [2]中国极地研究中心,上海200136

出　　处：《Applied Geophysics》2008年第3期230-237,共8页应用地球物理（英文版）

基　　金：the National Natural Science Foundation of China(Grant No.40874060);the 863 projection(Grant No.2006AA09Z152)

摘　　要：The ice exceeding one million years old has significant meaning for verifying and interpreting the middle Pleistocene transition （MPT） and the relationship between greenhouse gas and climate change. The region near Dome A in Antarctica satisfies the conditions for obtaining million-years-old ice since it has low temperatures and low accumulation rates. We analyze the corresponding relation between radar wave features and the crystal orientation fabric （COF） types based on the results of multi-polarization plane radio echo sounding （RES）. The results show that, even in the summit of the ice sheet, the COF type is not perfect, but is an elongated single-pole COF. Principal-axis-orientation differences of the COF among the different periods exist and reveal that the ice flow orientations are not constant but deviate clockwise with the increasing depth. This may be related to the adjacent basal valley or both height and position changes of the summit during the glacial-interglacial periods.年代超过百万年的古老冰体对于验证和解释中更新世气候转型(MPT)以及温室气体与气候变迁的关系具有重要意义。Dome A区域的低温、低积累率满足最有可能获取年代超过百万年的古老冰体的条件。本文基于多极化冰雷达探测结果,来分析Dome A区域冰盖内部雷达反射特征与冰晶组构类型的对应关系。结果显示即使在冰盖最高点,冰晶组构也不是理想单极大型,而是水平方向存在拉伸的单极大型,且不同时期的冰组构主轴方向存在差异;这种差异揭示Dome A区域古冰流方向不是恒定不变的,而是随着深度增加存在顺时针偏转。这可能与邻近的冰床沟谷或冰期间冰期冰盖最高点位置的改变有关。

关 键 词：Crystal orientation fabric （COF） radio echo sounding （RES） multi-polarization plane technique ice flow orientation 

分 类 号：P343.6[天文地球—水文科学]