2009/2010年内蒙古冬季低温特征及成因分析

利用常规观测资料，分析2009/2010年内蒙古冬季低温的特征。并通过对欧亚地区大气环流、影响我国的冷空气活动、北极涛动指数和EI Nino年内蒙古冬季气温的分析，探讨此次低温的气候成因。结果表明：此次冬季低温是内蒙古自1986年以来范围最广、时间最长、强度最大的一次冬季低温。强降温的同时，还伴随着强降雪和大风沙尘天气。地面西伯利亚高压偏强、850 hPa内蒙古北侧偏北气流偏强、500 hPa位势高度场偏低、东亚大槽位置偏西偏强以及强冷空气活动频繁是造成此次低温的主要原因。此次低温还与北极涛动指数负异常和EI Nino事件有关。

Analysis on Characteristics and Formation Causes of Low Temperature in Inner Mongolia in Winter of 2009/2010

In this paper,the duration,range,intensity and influence of low temperature in Inner Mongolia in winter of 2009/2010 were analyzed.The formation causes of low temperature were also analyzed from the aspects of circulation over East Asia,cold air activity over Inner Mongolia,Arctic Oscillation and El Nino.The results show that Inner Mongolia suffered from the most serious low temperature which lasted for the longest period and affected the widest area in winter of 2009/2010 since 1986.Heavy snowfall,strong wind and serious sandstorm occurred when temperature dropped strongly.The low temperature was caused by the stronger Siberian High at surface,stronger northerly flow at 850 hPa over north Inner Mongolia,lower geopotential height at 500 hPa over Inner Mongolia,westward and stronger East Asian Trough at 500 hPa,and more frequent activity of strong cold air current than those in normal years.A statistic result shows that there was a significant positive correlation between Arctic Oscillation Index in winter and winter temperature in Inner Mongolia.A composite analysis reveals that the low temperature occurred in most area of Inner Mongolia in El Nino winter,and this conclusion was different from the achievements in previous studies.