Yang, S., Li, T., Hu, J., & Shen, X. (2017). Decadal variation of the impact of La Niña on the winter Arctic stratosphere. Advances in Atmospheric Sciences, 34(5), 679-684.
Decadal Variation of the Impact of La Nina on the Winter Arctic Stratosphere
Shuangyan YANG1,2, Tim LI1,2, Jinggao HU∗1,2, and Xi SHEN1
1Key Laboratory of Meteorological Disaster, Ministry of Education/Joint International Research Laboratory of Climate and Environmental Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing210044, China
2International Pacific Research Center and Department of Atmospheric Sciences, University of Hawaii at Manoa, Honolulu, Hawaii96822, USA
(Received 19 July 2016; revised 29 October 2016; accepted 19 December 2016)
The impact of La Nina on the winter Arctic stratosphere has thus far been an ambiguous topic of research. Contradictory results have been reported depending on the La Nina events considered. This study shows that this is mainly due to the decadal variation of La Nina’s impact on the winter Arctic stratosphere since the late 1970s. Specifically, during the period 1951–78, the tropospheric La Nina teleconnection exhibits a typical negative Pacific–North America pattern, which strongly inhibits the propagation of the planetary waves from the extratropical troposphere to the stratosphere, and leads to a significantly strengthened stratospheric polar vortex. In contrast, during 1979–2015, the La Nina teleconnection shifts eastwards, with an anomalous high concentrated in the northeastern Pacific. The destructive interference of the La Nina teleconnection with climatological stationary waves seen in the earlier period reduces greatly, which prevents the drastic reduction of planetary wave activities in the extratropical stratosphere. Correspondingly, the stratospheric response shows a less disturbed stratospheric polar vortex in winter.
Key words: La Nina, stratospheric polar vortex, decadal variation, planetary waves