2010年冬季江苏省雷暴异常活动与北极涛动的相关分析
投稿时间:2011-09-13  修订日期:2012-03-13  点此下载全文
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作者单位E-mail
张蓬勃 南京市气象局, 江苏 南京 210009 bobozpb@163.com 
姜有山 南京市气象局, 江苏 南京 210009  
姜爱军 南京市气象局, 江苏 南京 210009  
管兆勇 气象灾害教育部重点实验室(南京信息工程大学), 江苏 南京 210044
南京信息工程大学 大气科学院, 江苏 南京 210044 
 
孙佳丽 江苏省气候中心, 江苏 南京 210008  
刘梅 江苏省气象台, 江苏 南京 210008  
基金项目:青奥会期间高影响天气监测预警服务技术集成与应用(2011BAK21B04);科技厅科技支撑计划—社会发展项目(BE2011612);江苏省科技厅资助项目(BS2007088)
中文摘要:运用江苏省冬季雷暴日数统计数据和NCEP/NCAR再分析数据,在结合30 a江苏冬季雷暴异常变化可能机理的基础上,分析了2010年冬季雷暴异常变化的原因。结果表明:2010年冬季江苏省雷暴活动异常偏多,其异常变化与同期北极涛动环流异常有密切的负相关关系。AO(Arctic Oscillation)指数偏弱时江苏雷暴增多的天气原因主要是:1)中西伯利亚和西西伯利亚地区气压异常偏高,中纬度地区气压异常偏低,乌拉尔山以西有阻塞高压与之配合,因此东亚冬季风偏强,冷空气南下频繁。对流层低层30°N附近表现为异常暖中心,低层孟加拉湾水汽输送强盛,江苏处于水汽辐合中心,这样“上冷下暖”和“上干下湿”的配置不仅有利于引起大气异常上升运动,也易于不稳定层结的形成,利于雷暴天气的发生。2)30~50°N北太平洋中东部海温异常偏低,引起低层风场异常辐散,对应上空为异常的下沉运动,通过类似于沃克环流圈形式使得东亚同纬度地区低层辐合异常,有利于该地区异常气旋性环流的加强。
中文关键词:雷暴  北极涛动  负相关关系
 
Thunderstorm anomaly in Jiangsu Province in winter 2010 and its relationship with the Arctic Oscillation
Abstract:By using the monthly NCEP/NCAR data and the data of thunderstorms in Jiangsu Province from 1981 to 2010,the main causes for anomalous thunderstorms in Jiangsu in winter 2010 are analysed on the basis of the possible mechanism of typical episodes occurring in recent 30 years.Results show that there were more thunderstorms in winter of 2010 than normal in most areas of China,which was negatively related with the teleconnection circulation anomaly of the Arctic Oscillation (AO).When the AO was weaker than normal,the air pressure in Central Siberian and West Siberian were higher than normal while that in middle-latitude area was lower.At the same time,Ural blocking high played a supporting role,so the East Asia winter monsoon was stronger,which meant the cold air was stronger than normal.There was an anomalous warm center at 30°N of lower troposphere,which caused the intensification of water vapor transfer at Bay of Bengal and thus there would be a water vapour convergence center in Jiangsu.The distribution of "cold and dry upper-layer and warm and wet lower-layer" triggered upward movement of the air,which was beneficial for the occurrences of thunderstorms.The negative anomalies of SSTA in such regions as central and eastern North Pacific caused anomalous divergence,resulting in the anomalous downward movement of the air.It then caused anomalous convergence in the area of the same latitude in East Asia via Walker pattern and enhanced cyclonic circulation in both areas.
keywords:thunderstorms  Arctic Oscillation  negative correlation
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