The influence of bathymetry over circulation on the Amundsen Sea continental shelf

The influence of bathymetry over circulation on the Amundsen Sea continental shelf
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测深对阿蒙森海大陆架环流的影响

DOI：
10.1002/essoar.10512786.1
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发表时间：
2022
期刊：
--
影响因子：
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通讯作者：
Haigh M
Haigh M
中科院分区：
--
文献类型：
--
作者：
Haigh M

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像松岛冰川和斯韦茨冰川这样的冰盖终止于西南极东部阿蒙森海的冰架，它们的质量正在以比大陆上大多数其他冰川更快的速度减少。质量损失是由于底部融化，这是受深流的影响，深流被认为是由海底水深测量引导的，它将温暖的绕极深水从大陆架断裂输送到冰架。由于人为和自然的影响，近地表的风在一定的时间尺度上变化，控制着这种海流和相关的热量输送。在这项研究中，我们使用理想化的模式来再现阿蒙森海环流和热量输送的基本特征。其目的是阐明测深特征在形成环流和使热量能够从深海输送到大陆架方面的作用。沿大陆坡度的水深变化通过在南极坡锋引起断裂，将陆外CDW与更冷、更新鲜的陆架水域分开，从而加强了陆架上的热量输送。理想化的模型结果表明，阻止从别林豪森海向西深流入的海脊导致了大陆架上存在深气旋环流。这种环流的一部分是沿大陆架断裂向东流动的暗流。更广泛的气旋环流将最近流入大陆架的热量向南输送。这些基础性的调查将有助于完善未来实地考察和建模的目标。
Ice sheets such as Pine Island and Thwaites Glaciers which terminate at their ice shelves in the eastern Amundsen Sea, West Antarctica, are losing mass faster than most others about the continent. The mass loss is due to basal melting, this affected by a deep current thought to be guided by bottom bathymetry that transports warm Circumpolar Deep Water (CDW) from the continental shelf break towards the ice shelves. This current and associated heat transport are controlled by the near-surface winds that vary on a range of timescales due to both anthropogenic and natural effects. In this study we use idealised models to reproduce essential features of the Amundsen Sea circulation and heat transport. The aim is to elucidate the role of bathymetric features in shaping the circulation and in enabling heat transport from the deep ocean onto the continental shelf. Bathymetric variations along the continental slope enhance on-shelf heat transport by inducing breaks in the Antarctic Slope Front that separates off-shelf CDW from the colder, fresher shelf waters. The idealised model results imply that a ridge that blocks deep westward inflow from the Bellingshausen Sea leads to the existence of a deep cyclonic circulation on the shelf. Part of this circulation is an eastward undercurrent that flows along the continental shelf break. The broader cyclonic circulation transports heat that has been recently fluxed onto the shelf towards the south. These fundamental investigations will help refine the aims of future fieldwork and modelling.