Evidence linking Arctic amplification to extreme weather in mid-latitudes
Evidence linking Arctic amplification to extreme weather in mid-latitudes
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DOI：
10.1029/2012gl051000
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发表时间：
2012-03-17
影响因子：
5.2
通讯作者：
Vavrus, Stephen J.
中科院分区：
文献类型：
--
作者：
Francis, Jennifer A.;Vavrus, Stephen J.
北极放大（AA）——观测到的北半球高纬度地区相对于北半球的变暖增强——在对流层较低温度和 1000 至 500 hPa 厚度中很明显。对来自国家环境预测再分析中心的每日 500 hPa 高度场进行了分析，以评估与 AA 相关的南北（罗斯比）波特征的变化以及向极地厚度梯度的松弛。确定了两种效应，每种效应都导致上层气流中罗斯贝波向东行进速度减慢：1）纬向风减弱，2）波幅增加。这些影响在秋季和冬季尤其明显，与海冰损失一致，但在夏季也很明显，可能与高纬度陆地上积雪提前融化有关。高空波浪进展缓慢将导致中纬度地区的相关天气模式更加持久，这可能导致干旱、洪水、寒流和热浪等长期条件导致极端天气事件发生的可能性增加。引用：Francis, J. A. 和 S. J. Vavrus (2012)，将北极放大与中纬度地区极端天气联系起来的证据，地球物理学。资源。快报，39，L06801，doi：10.1029/2012GL051000。
Arctic amplification (AA) - the observed enhanced warming in high northern latitudes relative to the northern hemisphere - is evident in lower-tropospheric temperatures and in 1000-to-500 hPa thicknesses. Daily fields of 500 hPa heights from the National Centers for Environmental Prediction Reanalysis are analyzed over N. America and the N. Atlantic to assess changes in north-south (Rossby) wave characteristics associated with AA and the relaxation of poleward thickness gradients. Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves. Citation: Francis, J. A., and S. J. Vavrus (2012), Evidence linking Arctic amplification to extreme weather in mid-latitudes, Geophys. Res. Lett., 39, L06801, doi:10.1029/2012GL051000.