2008年重庆冬季低温天气的环流异常特征

本文利用2008年1月12日~2月2日重庆34个测站逐日气温和降水资料,以及NCEP/NCAR全球逐日高度场、风场和比湿场的再分析资料,分析了2008年1月中下旬~2月初重庆地区低温雨雪冰冻天气的环流异常特征。结果表明,2008年初的低温雨雪冰冻天气是由亚洲高、低纬度地区异常的大气环流共同作用而产生。其中,中高纬度的亚洲区极涡、乌拉尔山阻塞高压和东亚大槽的异常,致使大量强冷空气在西伯利亚地区堆积,然后在蒙古冷高压的作用下从西伯利亚经蒙古进入我国。同时来自低纬地区的西南暖湿气流从西南地区进入我国,与来自北方的冷空气在长江流域及其以南地区相遇,形成冷暖气流的辐合带。当势力相当的冷暖气流在长江流域及其以南地区相遇并维持,势必使受其控制区域出现大面积持续性的低温雨雪冰冻天气。 

Atmospheric Circulation Features of Winter Lower Temperature in Chongqing in 2008

Based on the meteorological data of daily temperature and rainfall data observed by 34 meteorological stations, and the daily mean reanalysis data of NCEP/NCAR (from January 11th to February 3rd) in 2008, the atmospheric circulation features of winter lower temperature in Chongqing are studied.The result indicates that the anomalous atmospheric circulation feature in high and low latitude over Asian leads to the lower temperature in Chongqing in 2008 early.The anomalous of Asian Polar Vortex, Ural Blocking and Siberian High over middle-high latitude made the strong cold air accumulating in Siberia, then the strong cold air entered in China from Siberia and Mongolia with Mongolia Cold High effecting.The cold air and the warm air from the low latitude encountered and formed the convergent zone over Yangtse River.The equiponderant cold air and warm air were keeping in South China which made the large area appearing the lower temperature weather.