Landfast ice controls on sea-ice production in the Cape Darnley Polynya: A case study
Landfast ice controls on sea-ice production in the Cape Darnley Polynya: A case study
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DOI：
10.1016/j.rse.2019.111315
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发表时间：
2019-11-01
影响因子：
13.5
通讯作者：
Willmes, Sascha
中科院分区：
文献类型：
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作者：
Fraser, Alexander D.;Ohshima, Kay I.;Willmes, Sascha
南极沿海冰穴是至关重要的海冰“工厂”，（在某些情况下）作为南极底层水（AABW）形成的地点具有全球意义，例如，位于南极洲东部的达恩利角。因此，了解其行为的变化和可变性以及造成这种变化的因素，是气候（变化）科学的一个高度优先事项。其中一个重要的因素，既不了解和量化是他们与邻近的陆地固定海冰（固定冰）的联系。在这里，我们提出了第一个详细的分析，确定和量化的动态/行为的CDP和快冰之间的关键联系。通过在东部边界形成对浮冰入侵的屏障，CDP上游的快冰（与搁浅冰山的分布有关）在冰间湖的形成、维持和变化中起着至关重要的作用。这项基于卫星数据的研究建立在早期的概念性工作上的冰间融冰反馈机制在默茨冰川地区的海冰生产率（因此AABW形成）的统计估计在CDP显着改善，通过纳入两个关键的快冰指标相比，单独使用大气协变量。这两个指标分别是冰穴上游的快冰范围和高海冰生成区域内的总快冰面积。这项工作强调了在全球气候模式中准确表示南极沿海冰间冰-坚冰系统的重要性。
Antarctic coastal polynyas serve as crucially-important sea-ice "factories" and are (in certain cases) of global significance as sites of Antarctic Bottom Water (AABW) formation e.g., the Cape Darnley Polynya (CDP) in East Antarctica. As such, understanding change and variability in their behaviour, and the factors responsible, is a high priority in climate (change) science. One such important factor that is both poorly understood and quantified is their linkage with adjacent landfast sea ice (fast ice). Here, we present a first detailed analysis that identifies and quantifies key linkages between the dynamics/behaviour of the CDP and fast ice. By forming a barrier to the incursion of pack ice at the eastern boundary, fast ice immediately upstream of the CDP (associated with the distribution of grounded icebergs) plays a crucially-important role in the polynya formation, maintenance and variability. This satellite data-based study builds upon earlier conceptual work on polynya-fast ice feedback mechanisms in the Mertz Glacier region by showing that statistical estimation of the rates of sea ice production (and hence AABW formation) in the CDP is significantly improved through inclusion of two key fast-ice metrics, compared to use of atmospheric covariates alone. These two metrics are the meridional extent of fast ice upstream of the polynya and total fast ice area within the region of high sea ice production. The work highlights the importance of accurate representation of the coupled Antarctic coastal polynya-fast ice system in global climate models.