The effect of changing sea ice on the physical vulnerability of Arctic coasts
The effect of changing sea ice on the physical vulnerability of Arctic coasts
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海冰变化对北极海岸物理脆弱性的影响
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
R. Anderson
中科院分区：
文献类型：
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作者：
K. Barnhart;I. Overeem;R. Anderson
海冰在北极冬季限制了陆地和海水的相互作用，并在夏季通过控制取水来影响这种相互作用。在北极的许多地区，开放水域季节的持续时间正在增加，夏季海冰面积正在减少。海冰对北极海岸的物理脆弱性提供了一级控制，以应对海水侵蚀、淹没以及对住区和基础设施的破坏。我们通过卫星记录询问海冰覆盖的变化是如何影响海岸侵蚀的。首先，我们提出了一个基于卫星的泛北极海冰浓度分析，特别是沿北极海岸。与1979年相比，2012年开放水域季节的中位数长度增加了1.5至3倍，其中北冰洋部分允许在北极风暴秋季开放水域。其次，我们提出了阿拉斯加德鲁点的一个案例研究，这是一个位于波弗特海的地点，其特征是富含冰的永久冻土和快速的海岸侵蚀率，在那里开放水域季节的持续时间和到海冰边缘的距离，特别是向西北方向，都增加了。在德鲁角，来自西北风导致海岸水位上升，并控制了海底切口的过程，这是海岸撤退的限速步骤。在开放水域条件下，到海冰边缘的距离通过对取流的控制来控制水位和波场。我们发现水位设置的极值随取水量的增加而增加。
Sea ice limits the interaction of the land and ocean water in the Arctic winter and influences this interaction in the summer by governing the fetch. In many parts of the Arctic, the open-water season is increasing in duration and summertime sea-ice extents are decreasing. Sea ice provides a first-order control on the physical vulnerability of Arctic coasts to erosion, inundation, and damage to settlements and infrastructures by ocean water. We ask how the changing sea-ice cover has influenced coastal erosion over the satellite record. First, we present a pan-Arctic analysis of satellite-based sea-ice concentration specifically along the Arctic coasts. The median length of the 2012 open-water season, in comparison to 1979, expanded by between 1.5 and 3-fold by Arctic Sea sector, which allows for open water during the stormy Arctic fall. Second, we present a case study of Drew Point, Alaska, a site on the Beaufort Sea, characterized by ice-rich permafrost and rapid coastal-erosion rates, where both the duration of the open-water season and distance to the sea-ice edge, particularly towards the northwest, have increased. At Drew Point, winds from the northwest result in increased water levels at the coast and control the process of submarine notch incision, the rate-limiting step of coastal retreat. When open-water conditions exist, the distance to the sea ice edge exerts control on the water level and wave field through its control on fetch. We find that the extreme values of water-level setup have increased consistently with increasing fetch.