Pathways of basal meltwater from Antarctic ice shelves: A model study
Pathways of basal meltwater from Antarctic ice shelves: A model study
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DOI：
10.1002/2014jc009915
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发表时间：
2014-09-01
影响因子：
3.6
通讯作者：
Hasumi, Hiroyasu
中科院分区：
文献类型：
--
作者：
Kusahara, Kazuya;Hasumi, Hiroyasu
我们调查的基础融水从所有南极冰架使用环极耦合冰架海冰海洋模型，再现南大洋环流的主要特征，包括南极绕极流（ACC）释放的传播途径。几个独立的虚拟示踪剂被用来确定详细的路径的基础融水。由于融水是由当地环境海洋环流输送的，因此融水示踪剂的传播途径取决于形成地点。南极冰架融水在南极洲南极大陆边缘的表层和次表层被有效地平流输送到低纬度地区，尽管大部分的底层融水存在于表层和次表层，但仍有一部分底层融水通过南极洲海岸边缘活跃的密水形成而进入底层。海底的信号沿着地形延伸，显示出类似于所观察到的南极底层水扩散的水平分布。来自威德尔海和罗斯海以及印度部分冰架的融水对海底信号有很大贡献。一系列忽略冰架与海洋热力相互作用的数值试验表明，各冰架底部的融水对南大洋的海冰和海洋热盐环流都有影响。
We investigate spreading pathways of basal meltwater released from all Antarctic ice shelves using a circumpolar coupled ice shelf-sea ice-ocean model that reproduces major features of the Southern Ocean circulation, including the Antarctic Circumpolar Current (ACC). Several independent virtual tracers are used to identify detailed pathways of basal meltwaters. The spreading pathways of the meltwater tracers depend on formation sites, because the meltwaters are transported by local ambient ocean circulation. Meltwaters from ice shelves in the Weddell and Amundsen-Bellingshausen Seas in surface/subsurface layers are effectively advected to lower latitudes with the ACC. Although a large portion of the basal meltwaters is present in surface and subsurface layers, a part of the basal meltwaters penetrates into the bottom layer through active dense water formation along the Antarctic coastal margins. The signals at the seafloor extend along the topography, showing a horizontal distribution similar to the observed spreading of Antarctic Bottom Water. Meltwaters originating from ice shelves in the Weddell and Ross Seas and in the Indian sector significantly contribute to the bottom signals. A series of numerical experiments in which thermodynamic interaction between the ice shelf and ocean is neglected regionally demonstrates that the basal meltwater of each ice shelf impacts sea ice and/or ocean thermohaline circulation in the Southern Ocean.