东南极历史冰流速过估改正  

Overestimation Correction in Historical Ice Flow Velocity Mapping in East Antarctica

作　　者：李荣兴 何美茜[1,2] 葛绍仓 程远 安璐 LI Rongxing;HE Meixi;GE Shaocang;CHENG Yuan;AN Lu(College Surveying&Geo-informatics,Tongji University,Shanghai 200092,China;Center for Spatial Information Science and Sustainable Development Applications,Tongji University,Shanghai 200092,China;School of Cultural Heritage and Information Management,Shanghai University,Shanghai 200444,China;Institute for the Conservation of Cultural Heritage,Shanghai University,Shanghai 200444,China)

机构地区：[1]同济大学测绘与地理信息学院,上海200092 [2]同济大学空间信息科学及可持续发展应用中心,上海200092 [3]上海大学文化遗产与信息管理学院,上海200444 [4]上海大学文化遗产保护基础科学研究院,上海200444

出　　处：《武汉大学学报（信息科学版）》2023年第10期1661-1669,共9页Geomatics and Information Science of Wuhan University

基　　金：国家重点研发计划(2017YFA0603102);国家自然科学基金(41730102,41771471);中央高校基本科研业务费专项资金(22120170152)。

摘　　要：南极冰盖表面冰流速是准确估算冰盖物质平衡和预测全球海平面变化的关键参数之一。针对冰流速提取中存在的流速过估现象,采用东南极20世纪60-80年代历史冰流速重建数据集,分析了整个东南极冰盖及不同海洋扇区、冰架/冰川过估改正量的空间分布规律。统计结果表明,东南极过估改正量的平均值约为28 m/a;在接地区和冰架前缘附近,过估改正量峰值高于其他区域,其中接地区最大过估改正量超过300 m/a。在海域尺度上,东印度洋海域在接地区和冰架区冰流速过估的现象较其余海域更加明显,其冰架区的平均过估改正量约为62 m/a;在冰架/冰川尺度上,Shirase冰川、Holmes冰川、Ninnis冰川、Publications冰架以及Totten冰川的平均改正量均超过50 m/a,高于整个东南极改正量的平均值。结合过估改正量与历史冰流速提取结果,证明改正量的分布在一定程度上符合冰流空间加速的规律。流速改正已应用于东南极20世纪60-80年代历史冰流速产品,对研究冰架稳定性、进一步研究全球变暖影响下的南极冰盖动态稳定具有重要意义。Objectives Reconstruction of ice flow velocity on the Antarctic Ice Sheet plays a critical role in estimating mass balance and contribution to global sea level rise.However,due to the low availability of optical satellite images before the 1990s,the time span of image pairs ranges from several years to more than ten years,leading to velocity overestimations.In this study,we correct the overestimated ice flow velocity based on the Lagrangian framework.After correction,we analyze the distribution of the overestimation values in the East Antarctic Ice Sheet(EAIS)according to the space and magnitude.Methods We formulate a set of correction rules,including filtering points of ice flow velocity before correction and whether to retain results after correction.As a transition zone between grounded ice and ice shelf,ice flow velocity near the grounding line is one of the most important parameters of the ice sheet mass balance.In this paper,the overestimations of ice flow velocity are mainly studied from three aspects:First from different regions icluding inland region,grounding region and ice shelf region,then from different ocean sectors icluding Weddell Sea,West Indian Ocean,East Indian Ocean and Ross Sea,finally from different glaciers/ice shelves.Results The average overestimation of ice flow velocity in EAIS is about 28 m/a.Both the grounding and ice shelf regions have larger overestimations than the inland region.The peak correction appears at±25 km near the grounding line,and the maximum correction exceeds 300 m/a.As for ocean sectors,the overestimation of velocity is the largest in the East Indian Ocean.The average corrections of the Holmes Glacier,Ninnis Glacier,Publications Ice Shelf,and Totten Glacier in this sector exceed 50 m/a,much larger than that of EAIS.Conclusions This paper shows that only a very small proportion of ice velocity points can meet the correction rules.The points show differences in regional distribution and they are concentrated mainly in the fast-flowing areas such as glaciers and ice sh

关 键 词：东南极冰盖 冰流速 过估改正 

分 类 号：P228[天文地球—大地测量学与测量工程]