The Role of Sea Ice in Arctic and Antarctic Polynyas
The Role of Sea Ice in Arctic and Antarctic Polynyas
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DOI：
10.1016/s0422-9894(06)74001-6
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发表时间：
2007-01-01
期刊：
影响因子：
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通讯作者：
Massom, R. A.
中科院分区：
文献类型：
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作者：
Barber, D. G.;Massom, R. A.
冰裂谷是持续和反复出现的开放水域和/或薄冰或冰浓度降低的区域，面积达数万至数万平方公里，发生在两个半球的海冰带内，在气候上预计会有更坚固和更厚的冰盖。多冰湖不是简单地构成海冰中反复出现的“窗口”，而是受到当地甚至区域冰况的深刻影响，并与之密切相关（即“冰逃逸”）。它们对海洋和大气的热力学和动力强迫作出敏感反应，并产生生态上重要的“绿洲”，使鸟类和哺乳动物能够在高纬度地区越冬，并促进春季初级生产的增加。在本文中，我们从海冰条件/过程的角度介绍了冰融现象的概念。我们讨论了两极多冰湖的独特特征，并评估了它们对气候变率和变化的可能响应/贡献。本文主要基于卫星数据分析，但也基于文献和土著居民的信息，提出了北半球多冰湖的清单。还提供了冰湖开放和关闭日期的简要统计数据，以及与海冰季节周期有关的光的可用性信息。在南半球，我们更新了南极多冰湖的清单，并讨论了海岸、冰川和深海过程如何影响它们的分布。更详细地考察了两个重要的融冰区，即北部的北水融冰区和南部的默茨冰川融冰区。这些案例研究侧重于推动其创建、维护和解散的不同物理过程的细节。近年来，每一个冰穴都是专门的就地研究方案的重点。
Polynyas are persistent and recurrent regions of open water and/or thin ice or reduced ice concentration, tens to tens of thousands of square kilometers in areal extent, that occur within the sea ice zones of both hemispheres at locations where a more consolidated and thicker ice cover would be climatologically expected. Rather than simply constituting recurrent "windows" in the sea ice, polynyas are profoundly affected by, and intimately linked to, local and even regional ice conditions (i.e., the "icescape"). They respond sensitively to thermodynamic and dynamic forcing by the ocean and atmosphere and entail ecologically important "oases" that enable birds and mammals to overwinter at high latitudes and encourage enhanced primary production in the spring. In this review, we introduce the concept of polynyas from the perspective of the sea ice conditions/processes that define them. We discuss the unique characteristics of polynyas in both polar regions, and assess their possible response/contribution to climate variability and change. An inventory of Northern Hemisphere polynyas is presented, based primarily of satellite data analysis but also on information from the literature and aboriginal peoples. Summary statistics on polynya opening and closing dates are also provided, along with information on the availability of light relative to the seasonal cycles of sea ice. In the Southern Hemisphere, we present an update of an inventory of Antarctic polynyas and discuss how coastal, glacial and deep-ocean processes affect their and distribution. Two important polynyas are examined in more detail, i.e., the North Water (NOW) polynya in the north and the Mertz Glacier polynya in the south. These case studies focus on details of the different physical processes driving their creation, maintenance and dissolution. Each of these polynyas has been the focus of dedicated in situ research programmes in recent years.