The Shelf Circulation of the Bellingshausen Sea
The Shelf Circulation of the Bellingshausen Sea
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DOI：
10.1029/2020jc016871
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发表时间：
2021-05-01
影响因子：
3.6
通讯作者：
LoBuglio, C.
中科院分区：
文献类型：
--
作者：
Chretien, L. M. Schulze;Thompson, A. F.;LoBuglio, C.
近几十年来，西南极冰盖经历了其浮动冰架的快速变薄以及其海洋终止冰川的接地线退缩。沿着西南极半岛（WAP）和阿蒙森海广泛记录的暖变性绕极深水（MCDW）向大陆架的输送已被确定为引起这些变化的关键过程。别林斯高晋海位于阿蒙森海和WAP的北方部分之间，但与周围地区相比，其海洋性质仍然受到严重的研究。在这里，我们介绍了2019年夏季对别林斯高晋海大陆架进行的水文调查中收集的观测结果。使用船舶和滑翔机为基础的CTD和降低ADCP观测相结合，我们表明，海底槽提供地形转向路径MCDW从陆架断裂到深海湾，并最终在浮动冰架。温暖的MCDW进入贝尔吉卡海槽最深处的大陆架，并沿着海槽东侧流向岸上。修改这些向岸流动的沃茨水估计通过计算融水分数使用最佳的多参数分析。融化的水被发现是升高在西部边缘的Latady和Belgica槽。融水分布，与其他诊断一致，建议在每个槽的再循环与修改后的沃茨最终向西流动后离开比利时槽。我们的研究结果表明，别林斯高晋海是更大的西南极环流系统的一个重要组成部分，连接WAP和阿蒙森海。这被归因于一个温暖的水团，环极深水（CDW）。这种水已被观察到沿着西南极半岛（WAP）和阿蒙森海。位于WAP和阿蒙森海之间的别林斯高晋海也表现出类似的冰架变薄速度，但与东部和西部地区相比，研究仍然显着不足。我们从2019年初开始观察别林斯高晋海。温度和速度数据的组合被用来表明，海底槽提供的路径，从近海的温水到达冰盖。这发生在Belgica海槽的最深处，沿着Latady海槽的东侧，两个海槽之间现在稍微冷却的水再循环。来自冰盖的水沿着比利时海槽的西侧离开别林斯高晋海，然后向西流向阿蒙森海。我们的研究结果表明，这一地区是西南极环流系统的一个重要组成部分，连接WAP和阿蒙森海。
Over recent decades, the West Antarctic Ice Sheet has experienced rapid thinning of its floating ice shelves as well as grounding line retreat across its marine-terminating glaciers. The transport of warm Modified Circumpolar Deep Water (MCDW) onto the continental shelf, extensively documented along the West Antarctic Peninsula (WAP), and in the Amundsen Sea, has been identified as the key process for inducing these changes. The Bellingshausen Sea sits between the Amundsen Sea and the northern part of the WAP, but its oceanic properties remain remarkably under-studied compared to surrounding regions. Here, we present observations collected from a hydrographic survey of the Bellingshausen Sea continental shelf in austral summer 2019. Using a combination of ship-based and glider-based CTD and lowered ADCP observations, we show that submarine troughs provide topographically steered pathways for MCDW from the shelf break toward deep embayments and ultimately under floating ice shelves. Warm MCDW enters the continental shelf at the deepest part of the Belgica Trough and flows onshore along the eastern side of the trough. Modification of these shoreward-flowing waters by glacial melt is estimated by calculating meltwater fractions using an optimal multiparameter analysis. Meltwater is found to be elevated at the western edge of both the Latady and Belgica troughs. Meltwater distributions, consistent with other diagnostics, suggest a recirculation in each trough with modified waters eventually flowing westward upon leaving the Belgica Trough. Our results show that the Bellingshausen Sea is a critical part of the larger West Antarctic circulation system, linking the WAP and the Amundsen Sea.Plain Language Summary Over the past decades large changes in the volume of the West Antarctic Ice Sheet have been observed. This has been attributed to a warm water mass, the Circumpolar Deep Water (CDW). This water has been observed along the West Antarctic Peninsula (WAP) and in the Amundsen Sea. The Bellingshausen Sea, located between the WAP and the Amundsen Sea, has exhibited similar rates of ice shelf thinning, yet remains remarkably under-studied compared to regions to the east and west. We present observations of the Bellingshausen Sea from early 2019. A combination of temperature and velocity data are used to show that submarine troughs provide pathways for the warm water from offshore to reach the ice sheets. This takes place at the deepest part of the Belgica Trough and along the eastern side of the Latady trough with a recirculation of this now slightly cooler water between the two troughs. The water originating from the ice sheets leaves the Bellingshausen Sea along the western side of the Belgica Trough before flowing west toward the Amundsen Sea. Our results show that this region is a critical part of the West Antarctic circulation system, linking the WAP and the Amundsen Sea.