Little influence of Arctic amplification on mid-latitude climate
Little influence of Arctic amplification on mid-latitude climate
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DOI：
10.1038/s41558-020-0694-3
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发表时间：
2020-02-10
影响因子：
30.7
通讯作者：
Song, Mirong
中科院分区：
文献类型：
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作者：
Dai, Aiguo;Song, Mirong
观测（1-3）和模型模拟（3，4）显示，在温室气体增加的情况下，北极变暖加剧，这种现象被称为北极放大（AA）（5），可能是由海冰损失造成的（1，3）。AA降低了与环流相关的纬向温度梯度，因此中纬度天气和气候变化被归因于AA，通常基于回归分析和大气模拟（6-19）。然而，其他模拟研究（20-22）只显示了一个薄弱环节。这种不一致性可能是由于缺乏将AA的影响与自然变率或背景变暖的影响分开。在这里，使用耦合模式模拟和没有AA，我们表明，冷季降水，降雪和环流变化北方中纬度地区主要来自背景变暖。AA和海冰损失增加降水和降雪以上类似于60度N，并减少对流层中下层的纬向温度梯度以上类似于45度N。然而，对平均气候的影响最小的是在60度以下，在50 -70度N和150-700 hPa的纬向风减弱，主要是在北大西洋和北方中亚。这些结果表明，在高纬度以外的地区，AA的气候影响可能很小，因此，在将中纬度的变化归因于AA和海冰损失的统计分析的基础上，不能区分AA的影响，从其他相关的变化，在北极变暖已被认为是造成中纬度天气和气候变化需要谨慎。模拟结果表明，北极变化对高纬度以外地区的影响很小，背景全球变暖对中纬度冬季降水和风变化的影响更大。
Observations(1-3) and model simulations(3,4) show enhanced warming in the Arctic under increasing greenhouse gases, a phenomenon known as the Arctic amplification (AA)(5), that is likely caused by sea-ice loss(1,3). AA reduces meridional temperature gradients linked to circulation, thus mid-latitude weather and climate changes have been attributed to AA, often on the basis of regression analysis and atmospheric simulations(6-19). However, other modelling studies(20-22) show only a weak link. This inconsistency may result from deficiencies in separating the effects of AA from those of natural variability or background warming. Here, using coupled model simulations with and without AA, we show that cold-season precipitation, snowfall and circulation changes over northern mid-latitudes come mostly from background warming. AA and sea-ice loss increase precipitation and snowfall above similar to 60 degrees N and reduce meridional temperature gradients above similar to 45 degrees N in the lower-mid troposphere. However, minimal impact on the mean climate is seen below similar to 60 degrees N, with weak reduction in zonal wind over 50 degrees-70 degrees N and 150-700 hPa, mainly over the North Atlantic and northern central Asia. These results suggest that the climatic impacts of AA are probably small outside the high latitudes, thus caution is needed in attributing mid-latitude changes to AA and sea-ice loss on the basis of statistical analyses that cannot distinguish the impact of AA from other correlated changes.Warming in the Arctic has been thought to cause mid-latitude weather and climate changes. Simulations show Arctic changes have small influence outside of high latitudes, with background global warming exerting more influence over mid-latitude winter precipitation and wind changes.