Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice
Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice
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DOI：
10.1038/nclimate3241
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发表时间：
2017-04-01
影响因子：
30.7
通讯作者：
Steig, Eric J.
中科院分区：
文献类型：
--
作者：
Ding, Qinghua;Schweiger, Axel;Steig, Eric J.
在过去的三十年里，北极的海冰迅速减少，而变暖的速度大约是全球平均速度的两倍。然而，北极变暖和海冰减少之间的关系还没有得到很好的理解。在这里，我们提出的证据表明，自1979年以来，夏季大气环流的趋势可能对9月海冰范围的下降贡献了60%。格陵兰岛和北冰洋上空的反气旋环流与对流层正压结构的趋势增加了下降流长波辐射以上的冰变暖和湿润对流层低层。模型实验，再分析数据约束大气环流，复制所观察到的热力学响应，并指出，近地表的变化主要是由环流变化，而不是反馈不断变化的海冰覆盖。内部变化主导了北极夏季环流趋势，可能是自1979年以来9月海冰总体下降的30-50%。
The Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60% to the September sea-ice extent decline since 1979. A tendency towards a stronger anticyclonic circulation over Greenland and the Arctic Ocean with a barotropic structure in the troposphere increased the downwelling longwave radiation above the ice by warming and moistening the lower troposphere. Model experiments, with reanalysis data constraining atmospheric circulation, replicate the observed thermodynamic response and indicate that the near-surface changes are dominated by circulation changes rather than feedbacks from the changing sea-ice cover. Internal variability dominates the Arctic summer circulation trend and may be responsible for about 30-50% of the overall decline in September sea ice since 1979.