Weakening of the stratospheric polar vortex by Arctic sea-ice loss

• Published in: Nature communications Vol. 5; no. 1; p. 4646
• Main Authors: Kim, Baek-Min, Son, Seok-Woo, Min, Seung-Ki, Jeong, Jee-Hoon, Kim, Seong-Joong, Zhang, Xiangdong, Shim, Taehyoun, Yoon, Jin-Ho
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.09.2014; Nature Publishing Group
• Subjects: 704/106/125; 704/106/35; Economic impact; Humanities and Social Sciences; Ice cover; Latitude; Low temperature; multidisciplinary; Polar environments; Science; Science (multidisciplinary); Sea ice; Stratosphere; Vortices
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms5646

Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November–December), especially over the Barents–Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January–February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes. The mechanism behind the severely cold winters experienced by the mid-latitudes of the Northern Hemisphere in recent years is not fully understood. Here, the authors combine observational analyses and model experiments to reveal a dynamic connection between Arctic sea-ice cover and the polar stratosphere.