内蒙古极端低温事件发生的环流特征及预测概念模型

The Circulation Characteristics and Predictive Concept Model of Occurrence of Extreme Microtherm Event in Inner Mongolia

利用50a(1961—2010年)的日最低气温计算阈值,超过此阈值为极端低温事件。将内蒙古东、中、西部的极端最低气温事件进行四季划分统计,讨论分析这些地区的极端低温事件与大气环流、海洋因子的关系。分析研究表明:内蒙古极端低温事件主要发生在冬季(12月至次年2月),集中在20世纪60年代初至80年代中期,80年代中期至90年代末基本上没有发生,90年代末以后又陆续发生,但强度、范围明显减小。极端低温事件与北半球极涡、北极涛动、北太平洋涛动、南方涛动、海气相互作用、副热带高压、西风带环流存在着大体一致的年代际震荡趋势,同时与冷空气南下的路径有关,而且相关关系显著。通过相关检验,建立内蒙古极端低温事件的预测概念模型,以此应用于实际的业务当中,减少极端事件发生引发的各方面损失。

Using the daily minimum temperature of the 50 years （from 1961 to 2010） to calculate the threshold, and if the air temperature exceeded it, the event was defined as extreme microtherm event. Then we divided and counted the occurrence of extreme microtherm event of eastern, central and western in Inner Mongolia by seasons and analyzed the connection between the extreme microtherm event and atmospheric circulation, ocean factor. The conclusions showed that in the 1960s to the mid-1980s, the occurrence of main extreme microtherm event was in winter （from December to the next February）, then few occurrenced from the mid-80s to late 90s, in the late of 1990s it occurred in succession, but the intensity and scope were reduced obviously. The extreme microtherm event has generally consistent oscillation trend in the interannual change with the Northern Hemisphere polar vortex, the Arctic Oscillation, North Pacific Oscillation, Southern Oscillation, air-sea interaction, the subtropical high and westerly circulation, while a strong connection with the southward path of cold air exists. The conceptual model prediction was established according to the relevant test and was put into practical application to decrease losses caused by extreme microtherm events.