Agel Laurie, Cohen Judah, Barlow Mathew, Pfeiffer Karl, Francis Jennifer, Garfinkel Chaim I, Kretschmer Marlene
Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts Lowell, Lowell, MA 01854, USA.
Atmospheric and Environmental Research Inc., Lexington, MA 02421, USA.
Sci Adv. 2025 Jul 11;11(28):eadq9557. doi: 10.1126/sciadv.adq9557.
Mid-latitude Northern Hemisphere extreme cold events continue to occur despite overall winter warming trends. These events have been linked to weakened stratospheric polar vortex (SPV) states. In this study, we analyze both the upper and lower polar stratosphere for links to extreme winter cold and snow in the continental US, finding two SPV variations of interest. The first features an upper-level vortex displaced toward western Canada and linked to northwestern US severe winter weather. The second features a weakened upper-level vortex displaced toward the North Atlantic and linked to central-eastern US severe winter weather. Both variations feature lower-level stretched vortices and stratospheric wave reflection. Since 2015, a northwestward shift in severe winter weather across the US is concurrent with an increase in the frequency of the westward-focused variation relative to the eastward-focused variation and a shift to more negative phases of the El Niño-Southern Oscillation.
尽管冬季总体呈变暖趋势，但北半球中纬度地区仍持续出现极端寒冷事件。这些事件与平流层极地涡旋（SPV）状态减弱有关。在本研究中，我们分析了极地平流层的上层和下层，以寻找与美国大陆冬季极端寒冷和降雪的联系，发现了两种有趣的SPV变化。第一种变化的特征是高层涡旋向加拿大西部偏移，并与美国西北部的严冬天气有关。第二种变化的特征是减弱的高层涡旋向北大西洋偏移，并与美国中东部的严冬天气有关。这两种变化都具有低层拉长的涡旋和平流层波反射的特征。自2015年以来，美国严冬天气的西北向转移与向西集中的变化相对于向东集中的变化频率增加以及厄尔尼诺-南方涛动转向更负相位同时发生。
