The Alaskan Arctic regime shift since 2017: A harbinger of years to come?
The Alaskan Arctic regime shift since 2017: A harbinger of years to come?
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DOI：
10.1016/j.polar.2022.100841
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发表时间：
2022-05-31
期刊：
影响因子：
1.8
通讯作者：
Overland, James E.
中科院分区：
文献类型：
--
作者：
Ballinger, Thomas J.;Overland, James E.
阿拉斯加北极气候变化的最新特征包括新的天气模式，其影响通过阿拉斯加海洋生态系统传播。多条观测证据提请注意过去五年（2017-2021年）是一个显着的变化时期。白令海冬季和春季的冰覆盖率在2018年和2019年非常低，这与阿留申低压（AL）转移到白令海西部以及覆盖极地急流（PJS）的脊状变化有关，该急流支持南风并减少冰的生长。气候学上的博福特高压和相关的博福特环流在2017年和2020年经历了多次冬季崩塌，这是现代再分析时代仅有的两次这样的事件。相比之下，从2012年到2016年，AL和PJS位于阿拉斯加湾的东南部，这支持了海冰的增长。最近的配置暴露的海洋表面和大气异常支持出现的区域大气环流海冰损失的反应。我们认为，2017年后的区域系统转变预示着一个时期的开始，主要海冰损失事件和相关影响的频率越来越高-洪水，延迟春季开花和海洋食物链中断-这比气候模型预测的要早。
Recent fingerprints of Alaskan Arctic climate change include new weather patterns whose impacts propagate through the Alaskan marine ecosystem. Multiple lines of observational evidence draw attention to the last five years (2017-2021) as a remarkable period of change. Bering Sea winter and spring ice coverage was remarkably low in 2018 and 2019 associated with a shifted Aleutian Low (AL) into the western Bering Sea, and ridging of the overlying polar jet stream (PJS) that supported southerly winds and reduced ice growth. The climatological Beaufort High and associated Beaufort Gyre saw multiple winter-long collapses (2017 and 2020), the only two such events of the modern reanalysis era. In contrast, from 2012 to 2016 the AL and PJS were located southeastward across the Gulf of Alaska, which supported sea ice growth. The recent collocation of the exposed ocean surface and atmospheric anomalies supports the emergence of a regional atmospheric circulation response to seaice loss. We propose that the regional system shift after 2017 foreshadows the beginning of a period with an increasing frequency of major sea-ice loss events and associated impacts - floods, delayed spring blooms, and marine food chain disruptions - which is sooner than projected by climate models.