秋季北极海冰对中国冬季气温的影响

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

中文关键词:  北极海冰  冬季气温  日气温变率  异常低温天气

英文关键词:Arctic sea ice  Winter air temperature  Daily air temperature variability  Extreme cold weather

中文摘要:

      利用海冰资料、中国地面气候资料、环流特征量资料及NCEP/NCAR再分析资料，研究了秋季北极海冰变化对中国冬季平均气温、日气温变率以及异常低温天气的影响。分析结果表明，秋季北极海冰异常偏多年中国冬季常为暖冬；异常偏少年中国冬季常为冷冬，且异常低温天气出现频率更高，常发生低温灾害事件。秋季北极海冰通过影响后期的北半球极涡、东亚冬季风和西伯利亚高压进而影响中国冬季的平均气温，且通过影响冬季异常强西伯利亚高压的出现频次，影响中国冬季异常低温天气的发生频次。合成分析结果表明，秋季北极海冰异常偏少年的冬季，中国以北亚欧大陆高纬度的偏北风较强，且中国及其以北的中高纬度地区空气异常偏冷，导致极地和高纬度的冷空气易向南爆发，造成中国冬季气温偏低，异常低温天气频发。

英文摘要:

      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.