Ice-flow structure and ice dynamic changes in the Weddell Sea sector of West Antarctica from radar-imaged internal layering
Ice-flow structure and ice dynamic changes in the Weddell Sea sector of West Antarctica from radar-imaged internal layering
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DOI：
10.1002/2014jf003291
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发表时间：
2015-04-01
影响因子：
3.9
通讯作者：
Siegert, Martin J.
中科院分区：
文献类型：
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作者：
Bingham, Robert G.;Rippin, David M.;Siegert, Martin J.
最近的研究引起了人们的关注，即如果来自费尔奇纳-罗恩冰架的支撑减少，西南极洲威德尔海部分的冰可能会在海平面贡献中发挥更重要的作用。为了提高对全新世冰流动力学演变的理解，我们询问了来自研究所和穆勒冰流（IIS和MIS）流域的无线电回波测深（RES）数据，特别关注使用内部分层来研究冰流变化。作为这项工作的一个重要组成部分，我们研究了RES采集轨迹相对于冰流的方向对内部分层的影响，并发现除非RES飞行轨迹与冰流平行，否则这种影响很小。我们还研究了内部分层特征随深度的潜在变化，以寻找冰流状态的重要时间转变。我们的研究结果表明，IIS北部的冰在整个全新世期间一直保持着目前的冰流结构，使埃尔斯沃思冰下高地干涸。这与IIS南部和MIS大部分地区较少地形限制的冰形成对比，其内部分层表明过去类似于10,000年的冰流配置的空间变化。我们的研究结果证实了Siegert等人（2013）的推断，即在全新世晚期，Bungenstock冰升的快速水流被转移，并表明这可能只是随着南极西部冰盖自末次盛冰期以来变薄，在IIS和MIS流域发生的更广泛的冰流区域变化的一个组成部分。
Recent studies have aroused concerns over the potential for ice draining the Weddell Sea sector of West Antarctica to figure more prominently in sea level contributions should buttressing from the Filchner-Ronne Ice Shelf diminish. To improve understanding of how ice stream dynamics there evolved through the Holocene, we interrogate radio echo sounding (RES) data from across the catchments of Institute and Moller Ice Streams (IIS and MIS), focusing especially on the use of internal layering to investigate ice-flow change. As an important component of this work, we investigate the influence that the orientation of the RES acquisition track with respect to ice flow exerts on internal layering and find that this influence is minimal unless a RES flight track parallels ice flow. We also investigate potential changes to internal layering characteristics with depth to search for important temporal transitions in ice-flow regime. Our findings suggest that ice in northern IIS, draining the Ellsworth Subglacial Highlands, has retained its present ice-flow configuration throughout the Holocene. This contrasts with less topographically constrained ice in southern IIS and much of MIS, whose internal layering evinces spatial changes to the configuration of ice flow over the past similar to 10,000years. Our findings confirm Siegert et al.'s (2013) inference that fast flow was diverted from Bungenstock Ice Rise during the Late Holocene and suggest that this may have represented just one component of wider regional changes to ice flow occurring across the IIS and MIS catchments as the West Antarctic Ice Sheet has thinned since the Last Glacial Maximum.