春季北方气旋活动特征及其与中高纬海温场的关系

摘要

This paper statistically analyzed the characteristics of northern cyclonic activity in spring and its relationship with raid - high latitude sea surface temperature and general circulation by using the data of daily sea level pressure, monthly pacific sea surface temperature and monthly 500 hPa geopotential height provided by NCEP/NCAR reanalysis. The results showed that the northern cyclonic activity was frequent in spring, and it had two high value centres; in the middle part of Mongolia and in the northeast of our country. There was better correlation between the frequent activity of northern cyclone in spring and the prior mid - high latitude sea surface temperature, especially in Alaska area, the significantly negative correlation between them was always kept from September of last year to February of this year. There was obvious difference in prior sea surface temperature of key areas between abundant cyclonic activity year and poor cyclonic activity year, and the cumulative effect of abnormal sea surface temperature in above two characteristic years on the general circulation expressed in spring, the 500 hPa geopotential height expressed the opposite situation, and it caused the weakness and strengthening of zonal circulation, thus led to the increase and decrease of middle - latitudes cyclonic activity.%利用近55年NCEP/NCAR再分析逐日海平面气压场资料以及太平洋月平均海温场和500 hPa月平均位势高度场资料,统计了春季北方气旋活动频数的时空变化特征,并分析了其与中高纬海温场和大气环流的关系.结果表明:春季北方气旋活动频繁,存在着明显的两个高值中心,分别位于蒙古国的中部和我国东北北部地区；春季北方气旋活动频数与前期的中高纬太平洋海温场有较好的相关性,尤其东亚气旋的移栖地阿拉斯加湾地区为很好的相关持续区,从上一年9月开始一直到当年2月始终维持显著的负相关；气旋活动特多年与特少年的前期关键区的海温存在显著差异,两种特征年前期海温异常对大气环流影响的累积效应到春季突出表现出来,在当年春季,500 hPa高度场表现出明显的反相分布形势,而这种形势导致了纬向环流的减弱和增强,进而使得中纬的气旋性活动增加与减少.