The influence of the autumn Arctic sea ice on winter air temperature in China

Based on the sea ice data, the surface climate data in China, the circulation index and the NCEP/NCAR reanalysis data, the influence of the autumn Arctic sea ice on the mean surface air temperature, daily mean temperature variability and frequency of extreme cold event for winter in China was examined. The analysis shows that, in generally, the warmer winter in China occurs under more autumn Arctic sea ice years and colder winter with high frequency of extreme cold event occurs in the years of less autumn Arctic sea ice. Through influencing the polar vortex of Northern Hemisphere and the Eastern Asia winter monsoon and the Siberian high, the autumn Arctic sea ice plays an important role for mean winter air temperature in China, in which the autumn Arctic sea ice affects the frequency of extreme cold events through its influence on the frequency of the extreme high Siberia high. The composite analysis shows that there is stronger north wind over the high latitude area of Eurasia and it is colder in China and over the mid-high latitude region north of China during the years of less autumn Arctic ice, which induces colder winters and extreme cold events in China with the southward breakout of cold air from Arctic and the high latitudes.