中国冬季持续性低温事件的低频特征以及中低纬大气低频振荡对其的影响  

THE INTRASEASONAL CHARACTERISTICS OF WINTERTIME PERSISTENT COLD ANOMALY IN CHINA AND THE ROLE OF LOW FREQUENCY OSCILLATION IN THE LOW LATITUDE AND MIDLATITUDE

作　　者：朱毓颖[1,2] 江静[1] 

机构地区：[1]南京大学大气科学学院,江苏南京210093 [2]江苏省气象科学研究所,江苏南京210009

出　　处：《热带气象学报》2013年第4期649-655,共7页Journal of Tropical Meteorology

基　　金：国家科技支撑计划(2009BAC51B01);教育部博士点基金(200802840022)共同资助

摘　　要：根据中国气象局提供的1979 1980—2009 2010的31个冬季中国553个台站的逐日日平均气温资料和中国冬季持续性低温发生的特点,提出了单站持续性低温事件和区域持续性低温事件的客观定义,并利用EOF分析、谱分析、滤波和合成分析等统计方法,描述和统计了我国冬季持续性低温事件的低频特征以及中低纬大气低频振荡在持续性低温事件发生过程中的作用。结果表明,在低纬度地区,赤道印度洋的热带对流活动通过经向垂直环流影响了持续性低温事件。另外,在中纬度地区,北太平洋中部低频反气旋的增强为低温事件的持续性做出了贡献;西伯利亚地区低频高压的加强提供了不断的冷空气;贝加尔湖-巴尔喀什湖低频横槽的加深与维持,有利于冷空气从偏西路径侵入中国。因此,中国冬季持续性低温事件是中低纬大气低频振荡共同作用的结果。Based on the daily mean temperature datasets at 553 stations in China from 31 winters （1979/1980--2009/2010）, an objective method is adopted to depict the winter PCAs （persistent cold anomaly） over China. According to the definition, the intraseasonal characteristics of the PCAs are analyzed by EOF analysis, spectrum analysis, filter and composite analysis. Further, the impacts of low frequency activities in tropical and midlatitude atmosphere are explained. The results show that the convections over the equatorial Indian Ocean affect the PCAs by the local meridional-vertical circulation. In addition, in midlatitude, an enhanced intraseasonal anticyclone over the central part of northern Pacific is helpful for the maintenance of the PCAs. The PCAs are also associated with an enhanced subseasonal Siberian high, which persistently provides cold air. The intensified intraseasonal transverse trough between Lake Baikal and Lake Balkhash is favorable for the cold air to continuously move southward to China. Hence, the wintertime PCAs result from the interaction between intraseasonal activities in the tropics and in the middle latitudes.

关 键 词：气候学 持续性低温事件 客观定义 大气低频振荡 

分 类 号：P423[天文地球—大气科学及气象学]