摘要
不少研究已经表明,乌拉尔阻塞高压的持续活动对2008年1月中国南方雨雪冰冻灾害的发生有重要作用。本文针对2008年1月乌拉尔阻塞高压的异常,利用NCEP再分析逐日环流资料、哈德莱中心的海温资料等,从对流层北极涛动(AO)、平流层极涡(PV)以及海温异常等几方面,对2008年1月乌拉尔阻塞高压异常产生的原因进行了分析研究。结果显示,虽然从以往多年情况来看,前期AO及平流层极涡的异常很可能会导致其后乌拉尔阻塞高压发生异常,然而就2008年1月的情况而言,2007～2008年冬季对流层AO和平流层极涡的异常都不能成为异常乌拉尔阻塞高压产生和偏强的原因,因为它们的关系与多年存在的长期关系相反。进一步的分析研究则显示,2007年12月和2008年1月赤道太平洋的LaNin～a事件也对乌拉尔阻塞高压的活动没有明显影响;而北大西洋海温正异常,尤其是北大西洋副热带海温正异常的存在,是2008年1月乌拉尔阻塞高压持续的重要外强迫因素。
Some studies have indicated that the continued activity of blocking high over the Ural Mountains plays an important role in the occurrence of the freezing rain and snow storm in South China during January 2008.To understand the anomalous activity of blocking high over the Ural Mountains further,this study will analyze the possible causes for this phenomenon from the aspects of the tropospheric Arctic Oscillation （AO）,the stratospheric polar vortex,and the sea surface temperature anomalies,using the daily NCEP/NCAR reanalysis data and the Hadley center HadISST1 data.The analyses results show that the Ural blocking high in January is significantly related to the AO and the stratospheric polar vortex during 1958-2007.However,the situation for 2008 does not fit in with such close relationship in the past 50 years,and the relation is opposite to that in the past 50 years.It means that the Ural blocking high in January 2008 is not closely related to the AO and the stratospheric polar vortex in the 2007-2008 winter.Further analyses indicate that the Ural blocking high is closely related to the positive sea surface temperature anomalies （SSTA） in the North Atlantic,particularly in the subtropical North Atlantic area,but not to the La Nia in the Pacific.The positive SSTA in the North Atlantic （especially in the subtropical North Atlantic） may act as one of the major external forcings for the anomaly of Ural blocking high.
出处
《大气科学》
CSCD
北大核心
2010年第5期865-874,共10页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展计划项目2007CB411805
