Kashiwase Haruhiko, Ohshima Kay I, Nihashi Sohey, Eicken Hajo
National Institute of Polar Research, Tachikawa, 190-8518, Japan.
Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan.
Sci Rep. 2017 Aug 15;7(1):8170. doi: 10.1038/s41598-017-08467-z.
Ice-albedo feedback due to the albedo contrast between water and ice is a major factor in seasonal sea ice retreat, and has received increasing attention with the Arctic Ocean shifting to a seasonal ice cover. However, quantitative evaluation of such feedbacks is still insufficient. Here we provide quantitative evidence that heat input through the open water fraction is the primary driver of seasonal and interannual variations in Arctic sea ice retreat. Analyses of satellite data (1979-2014) and a simplified ice-upper ocean coupled model reveal that divergent ice motion in the early melt season triggers large-scale feedback which subsequently amplifies summer sea ice anomalies. The magnitude of divergence controlling the feedback has doubled since 2000 due to a more mobile ice cover, which can partly explain the recent drastic ice reduction in the Arctic Ocean.
由于水和冰之间的反照率差异导致的冰反照率反馈是季节性海冰消退的一个主要因素，并且随着北冰洋向季节性冰盖转变，这一因素受到了越来越多的关注。然而，对这种反馈的定量评估仍然不足。在这里，我们提供了定量证据，表明通过开阔水域部分的热量输入是北极海冰消退的季节性和年际变化的主要驱动因素。对卫星数据（1979 - 2014年）的分析以及一个简化的冰 - 上层海洋耦合模型表明，融化初期不同的冰运动引发了大规模反馈，随后放大了夏季海冰异常。自2000年以来，由于冰盖流动性增强，控制反馈的离散程度增加了一倍，这可以部分解释北冰洋近期急剧的冰量减少。
