1948-2015年北半球平流层爆发性增温的统计特征和月际环流差异
投稿时间: 2018-01-13  最后修改时间: 2018-03-04  点此下载全文
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作者单位E-mail
王华曌 南京大学 whuazhao@yeah.net 
饶建 南京信息工程大学 raojian@nuist.edu.cn 
生宸 中国科学院大气物理研究所LASG实验室  
王博 甘肃省古浪县气象局  
基金项目:国家自然科学基金项目(41705024、41575041);国家重点研发计划(2016YFA0602104);南京信息工程大学科研启动金(2016r060)
中文摘要:本文利用NCEP第一套再分析资料,分析了过去68年(1948-2015)平流层爆发性增温(Stratospheric Sudden Warming, SSW)频次、强度和环流特征的月际差异。统计结果表明:1948-2015年北半球共发生30次SSW ,其集中发生在11-3月,而1-2月发生频次尤为集中,且SSW发生频次表现出显著的年代际变化特征。11-12月SSW比1-3月SSW的持续时间长。而3月SSW事件的强度最弱,持续时间最短。1月和3月SSW纬向平均信号下传得较深,而11月、12月和2月的环流信号仅能传到200 hPa。11-3月SSW爆发前1-2周500 hPa均观测到西太平洋遥相关型(Western Pacific, WP)的负位相;太平洋-北美遥相关型(Pacific-North America, PNA)的正位相仅仅出现在在11月、12月和3月SSW爆发前。SSW爆发后1-2周,仅有11月、1月和3月的事件对应着负位相的北大西洋涛动(North Atlantic Oscillation, NAO)。
中文关键词:平流层爆发性增温  月际  频次  强度  环流型
 
Statistical Characteristics of the Northern Hemisphere Stratospheric Sudden Warming (1948-2015)
Abstract:By using the National Centers for Environmental Prediction Reanalysis I (NCEP1) data, we compare the differences in frequency and intensity of stratospheric sudden warming (SSW), and its related circulation pattern during different cold months in the past 68 years (1948-2015) The statistical results show that there have occurred 30 SSWs since 1948, and SSWs mainly happen in cold months from November to March. SSWs occur more frequently in January and February than in other cold months. In addition, the frequency of SSWs is different from decade to decade. The composite results show that SSWs in November and December are significantly more persistent than in months from January to March. In contrast, SSWs in March seem to be much weaker and less persistent than those in other cold months. The tropospheric circulation and temperature anomalies associated with SSWs vary with timing of SSWs. The parallel comparison results indicate that the zonal mean signals associated with SSWs in January and March show a deeper downward propagation than those in November, December, and February, and that the zonal mean signals in November, December, and February can arrive deepest at 200 hPa. A negative Western Pacific (WP) like pattern is observed one or two weeks before SSW onset in all cold months. However, a positive Pacific-North America (PNA) like pattern only forms before SSW onset in November, December, and March. Moreover, a negative North Atlantic Oscillation (NAO) like pattern is observed one or two weeks after SSW onset in November, January, and March.
keywords:Stratospheric Sudden Warming (SSW)  Seasonality  Frequency  Intensity  Circulation pattern
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