CIC-FEMD/ILCEC, Key Laboratory of Meteorological Disaster of Ministry of Education (KLME), Nanjing University of Information Science and Technology, Nanjing, China.
Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA.
Sci Rep. 2017 Jun 19;7(1):3770. doi: 10.1038/s41598-017-03977-2.
East Asia experienced a record-breaking cold event during the 2015/16 boreal winter, with pronounced impacts on livelihood in the region. We find that this large-scale cold spell can be attributed to the concurrent super El Niño event in the tropical Pacific. Our analysis reveals that all super El Niño winters (1982/83, 1997/98, and 2015/16) were accompanied by a rapid sub-seasonal North Atlantic Oscillation (NAO)/Arctic Oscillation (AO) phase reversal from a positive to a negative state during early January, which was largely caused by the interaction of these super El Niño events with the subtropical jet annual cycle. The NAO/AO phase transition leads to a rapidly strengthened Siberian High, which favors southward intrusions of cold air to East Asia and thus causes severe local cooling. Similar cold spells can also be detected over Northern Europe associated with the fast sub-seasonal NAO/AO phase reversal. Due to the weaker amplitude of the ENSO forcing, these sub-seasonal atmospheric responses cannot be detected for moderate El Niño events. The super El Niño associated sub-seasonal signal of the East Asian and Northern Europe wintertime temperature responses carries important implications for future predictability of regional extreme events.
东亚在 2015/16 年冬季经历了破纪录的寒冷事件，对该地区的生计造成了明显影响。我们发现，这种大规模的严寒天气可归因于热带太平洋同时发生的超强厄尔尼诺事件。我们的分析表明，所有超强厄尔尼诺年的冬季（1982/83、1997/98 和 2015/16）都伴随着北大西洋涛动/北极涛动（NAO/AO）在 1 月初迅速从正位相向负位相转变，这主要是由这些超强厄尔尼诺事件与副热带急流年循环的相互作用引起的。NAO/AO 位相转变导致西伯利亚高压迅速增强，有利于冷空气向南侵入东亚，从而导致当地剧烈降温。类似的严寒天气也可以在与快速亚季节 NAO/AO 位相转变相关的北欧检测到。由于 ENSO 强迫的幅度较弱，对于中等强度的厄尔尼诺事件，这些亚季节大气响应无法被检测到。东亚和北欧冬季温度响应与超强厄尔尼诺相关的亚季节信号对未来区域极端事件的可预测性具有重要意义。
