Arid Zone Research ›› 2019, Vol. 36 ›› Issue (2): 348-355.

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Effects of NAO on the Extreme Cold Events in Xinjiang in Winter

CHEN Ying 1,LI Weijing2,SHI Hongzheng3,MAO Weiyi4   

  1. 1. Xinjiang Climate Center,Urumqi 830002,Xinjiang,China; 2. National Climate Center,Beijing 100081,China; 3. Xinjiang Meteorological Bureau,Urumqi 830002,Xinjiang,China; 4. Institute of Desert Meteorology,China Meteorological Administration,Urumqi 830002,Xinjiang,China

  • Received:2018-07-10 Revised:2018-08-21 Online:2019-03-15 Published:2019-03-12

Abstract: The frequency and circulation of extreme cold events in Xinjiang in winter were analyzed based on the daily air temperature data from the meteorological stations in Xinjiang,NCEP reanalysis data of the height field,wind field,temperature field and North Atlantic Oscillation (NAO) index during the period of 1961-2016. The variation of extreme cold events in Xinjiang in winter was affected by the Eurasia (EU) wave train transmission,in winter,however,there was no one to one corresponding negative correlation between the NAO phase and the extreme cold events in Xinjiang in winter. In the winter of NAO negative phase,NAO was spread by the EU wave train,and the north wind was weak in north of 70°N. Under this background,the extreme cold events in Xinjiang in winter were more (less) when the geopotential height over the Ural Mountain and its east region was high (low) and the west wind was weak (strong) in 50°-70°N. In the winter of NAO positive phase,NAO was spread by the EU wave train,and the north wind was strong in north of 70°N. Under this background,the extreme cold events in Xinjiang in winter were more (less) when the geopotential height over the Ural Mountain and its east region was high (low) and the west wind was weak (strong) in 50°-70°N. The result showed that the occurrence frequency of extreme cold events in Xinjiang was mainly affected by the interaction of NAO,the geopotential height field over the Ural Mountain and its east region and the west wind in 50°-70°N,of which,the west wind in 50°-70°N in winter and the geopotential height field over the Ural Mountain and its east region were the main affecting factors.

Key words: extreme cold event in winter, North Atlantic Oscillation, zonal circulation, Xinjiang