首页 产业信息 快讯[手机端] 政策研究 文献资源 标准规范 科研成果 企业展厅 文献传递 在线咨询 开放利用 高级搜索

Exceptionally persistent Eurasian cold events and their stratospheric link
作者 :  Finke, Kathrin; Hannachi, Abdel; Hirooka, Toshihiko
(^_^)

Persistent boreal winter cold spells (PCEs) can heavily strain the economy and significantly impact everyday life. While sudden stratospheric warmings are considered a precursor for Eurasian (EUR) cold events, these temperature extremes may occur during the full range of stratospheric variability. We investigate PCEs relative to the prevailing stratospheric polar vortex regime before their onset, with a particular focus on extremely weak (SSW) and strong (SPV) stratospheric winds by performing (lagged) composite analysis based on ERA5 reanalysis. On average, SPV PCEs that are concentrated over central EUR, are colder, shorter and set in more abruptly compared to SSW PCEs. A quasi-stationary, mid-tropospheric anticyclone over the Arctic Ocean that blocks warm air advection toward EUR is connected to the canonical downward progression of the negative North Atlantic Oscillation for SSW PCEs. In contrast, during SPV PCEs, the anticyclone is part of a Rossby wave having an origin co-located with negative wave activity flux anomalies over and being influenced by stratospheric wave reflection toward the North Atlantic. Its slow east-ward propagation is likely related to Arctic surface warming and unusually weak zonal winds over EUR.

关 键 词 :  Cold spells; Sudden stratospheric warming; Eurasia; Wave activity fluxes; Blocking; Extreme events
论文来源 :  ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES.0000,
语种 :  英文
所属领域 :  >>> 海洋科学研究
入库时间 :  2023-03-07
浏览次数 :  6