Future Arctic sea ice loss reduces severity of cold air outbreaks in midlatitudes
Future Arctic sea ice loss reduces severity of cold air outbreaks in midlatitudes
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DOI：
10.1002/2016gl068092
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发表时间：
2016-03-28
影响因子：
5.2
通讯作者：
Screen, James A.
中科院分区：
文献类型：
--
作者：
Ayarzagueena, Blanca;Screen, James A.
北极海冰减少对中纬度地区冷空气爆发（CAO）的影响尚不清楚。以前的研究已经定义了相对于当今气候的CAO，但以这种方式定义的CAO的变化可能反映了平均气候的变化，而不是天气变率的变化，社会对后者更敏感。在这里，我们重新讨论这个话题，但应用与当时气候条件相关的变化温度阈值。CAO的频率或持续时间不会随着预计的海冰损失而变化。然而，它们变得不那么严重，主要是由于温暖的极地空气平流，因为与CAO的发生相关的动力学基本上没有受到影响。CAO减弱，即使在中纬度地区，冬季平均温度下降，北极海冰损失的反应。这些结果是稳健的模拟两个大气模式规定不同的未来海冰状态和瞬态运行，其中包括外部强迫。
The effects of Arctic sea ice loss on cold air outbreaks (CAOs) in midlatitudes remain unclear. Previous studies have defined CAOs relative to the present-day climate, but changes in CAOs, defined in such a way, may reflect changes in mean climate and not in weather variability, and society is more sensitive to the latter. Here we revisit this topic but applying changing temperature thresholds relating to climate conditions of the time. CAOs do not change in frequency or duration in response to projected sea ice loss. However, they become less severe, mainly due to advection of warmed polar air, since the dynamics associated with the occurrence of CAOs are largely not affected. CAOs weaken even in midlatitude regions where the winter mean temperature decreases in response to Arctic sea ice loss. These results are robustly simulated by two atmospheric models prescribed with differing future sea ice states and in transient runs where external forcings are included.