【摘要】 从1955至56～1987至88年的33个冬季的14个突发性增温过程(简称SSW)中,选出5个最强的加以平均,分析了增温期及其前后期的平均环流特征。结果表明:(1)30hPa极点温度与30年平均温度距平值,增温期为17.1℃,前、后期分别为-4.7℃和-8.9℃。(2)在500hPa和50hPa高度场上,增温期比其前、后期波数都少,经向度较大。经向度发展和极涡分裂为二的现象首先出现在对流层。(3)5次SSW均属北太平洋增温,其相应的年份都是平流层由冬转夏,即季变“迟”的年份。更多还原

【Abstract】 In this paper, the mean circulation characteristics during the period of pre-, warming- and post-stages for 5 strongest sudden stratospheric wanning cases selected from 14 cases have been analysed.The results show:(1) The temperature anomaly at the North Pole at 30 hPa level is 17.1 ℃ in the warming-stage; -4.7 ℃, pre-stage; and-8.9 ℃, post-stage, respectively.(2) The wave number of the height fields at 500- and 50-hPa level during the warming-stage are less than the pre- and post-stage, the meridionality of the wave is larger.The development of the meridional circulation and the splitting of the Polar Vortex occured at the 500 hPa level firstly.(3) All of the 5 cases were North Pacific warmings and occured in the years of late seasonal transformation from Winter to Summer in stratosphere.更多还原