前期春季北太平洋海温异常与冬季北半球极涡的关系  

Relation between antecedent spring SST in North Pacific and winter polar vortex in northern hemisphere

作　　者：张婧雯[1,2] 李栋梁[1] 柳艳菊[3] 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044 [2]四川省防雷中心,成都610072 [3]国家气候中心,北京100081

出　　处：《气象科学》2015年第1期52-59,共8页Journal of the Meteorological Sciences

基　　金：国家重大科学研究计划(2013CB956004);国家重点基础研究发展计划(973计划)项目(2013CB430202);国家科技支撑计划项目(2009BAC51B02)

摘　　要：利用NCEP/NCAR再分析资料和NOAA海温资料,用EOF、相关分析等方法,分析了1960—2010年500 h Pa和100 h Pa等压面上北半球后冬(2月)极涡面积和前春(4月)北太平洋(20~60°N,120°E^120°W)海表温度(SST)的变化特征,揭示了二者的时空联系。结果表明:近50a来,(1)冬季北半球500 h Pa和100 h Pa极涡面积整体经历了先扩张后收缩的变化。春季北太平洋SST经历了先降低后升高的变化。其突变时间与500 h Pa极涡面积的突变时间相近,均出现在1987年,且与后冬500 h Pa大西洋欧洲大陆区(Ⅳ区)极涡面积相关更好。(2)春季北太平洋SST的EOF第一模态空间型表现为PDO,第二模态表现为三极子型,突变分别出现在1980s初期和中期。(3)北太平洋SST与500 h PaⅣ区极涡面积相关的空间分布表现为:当前期春季北太平洋中部海温异常偏高(低),南部和北部海温异常偏低(高),使得下一个冬季500 h PaⅣ区极涡面积的扩大(缩小),这种空间遥相关型对应着海温的第二模态。北太平洋海温异常以第一模态空间型居多,但是对后冬北半球极涡面积影响大的却是第二模态。(4)当前春北太平洋SST呈第二模态时,对应次年冬季中高纬度对流层温度"上冷下暖",极地东风和绕极西风环流加强,极涡面积偏大。By using the NCEP/NCAR reanalysis data and Sea Surface Temperature data from Had- ley center, the variation characteristics of the Polar Vortex Area（PVA） at 500 hPa and 100 hPa over northern hemisphere in late winter （February） during 1960-2010 and SST in North Pacific in antecedent spring （April） during 1959-2009 are investigated with methods of EOF and relevant analysis. Moreover, their temporal and spatial connections are also revealed. Results show that in recent 50 years the follwing four conclusions are available. （ 1 ） the size of PVA in northern hemisphere in winter at 500 hPa and 100 hPa has had an expansion-shrinkage trend and has mutated in 1987. The North Pacific SST has had a de- creasing-increasing trend and has mutated in 1987 too, which was significantly related to the PVA in the Atlantic and Europe part （IV part）. （2）The first and second EOF modes （EOF1 and EOF2） of North Pacific SST in spring spatially manifested as the structure of the PDO and tripole with the mutation in the antecedent and middle 1980s. （3）The spatial manifestation of the correlation between PVA and North Pacific SST corresponded to the EOF2. The high （low） SST in central North Pacific in antecedent spring and low （high） one in North and South might result in larger （smaller） PVA area at 500 hPa in the next February. The impact exerted by EOF2 mode of SST on PVA at 500 hPa was far more significant than that by EOF1 mode, although the EOF1 mode occurred more frequently. （4） When the North Pacific SST manifested as EOF2 mode, the corresponding temperature of troposphere in the next winter presented as “cold in the upper but warm in the low”, the easterlies and westerlies around the north pole strengthened and the size of PVA increased.

关 键 词：极涡面积 海温异常 EOF分析 相关分析 

分 类 号：P434.4[天文地球—大气科学及气象学]