南北涛动与南极涛动及北极涛动的相互作用

利用NCEP/NCAR再分析资料,分析了南北涛动（Interhemispheric Oscillation,IHO）与北极涛动（Arctic Oscillation,AO）和南极涛动（Antarctic Oscillation,AAO）的联系。分析表明：1）北极涛动（AO）、南极涛动（AAO）与全年各自半球中高纬度地表气压变化密切联系。其中,AO冬季强度最强,且在春季、冬季的影响范围大。而AAO对南半球中高纬的地表气压变动影响更为明显,其在夏季影响范围最大。2）南极涛动（AAO）与南北涛动（IHO）有很好的同期相关性,南极涛动可部分解释南北涛动的形成。IHO与AO存在不显著的负相关,南北半球中高纬大气运动具有相对独立性。3）南北涛动（IHO）与全球较大范围内的地面气压变化有关,而去除AAO信号后,夏季在南极地区原显著相关区显著减少,夏季AAO与IHO存在密切联系。4）南北涛动（IHO）主要与春季、秋季和冬季亚洲、欧洲北部地面气温关系密切。秋季最强,春季次之,冬季最弱。夏季IHO与全球地面气温没有较好的联系。亚欧大陆北部的热力作用可能部分地解释了南北涛动的形成。

Relationships among IHO,AO and AAO

Based on 1979—2007 seasonal NCEP/NCAR reanalysis data,relationships among Interhemispheric Oscillation （IHO）,Arctic Oscillation （AO） and Antarctic Oscillation （AAO） are investigated.The results are shown as follows：1） Both AO and AAO have close relationship with mid-high latitude surface pressure changes in their own hemispheres.AO in boreal winter emerge as strongest magnitude and influence broadly in both boreal spring and winter.AAO,on the other hand,exhibits most active in both austral summer and winter,and has notable impact on mid-high latitudes,especially in austral summer.2） IHO and AAO show significant positive correlation and AAO can partly explain the formation of IHO.IHO and AO exhibit insignificant negative correlations in all the four seasons.The relationships indicate that atmospheric circulation in mid-high latitudes in both the northern hemisphere （NH） and the southern hemisphere（SH） is relatively independent.3） IHO makes contributions to large scale surface pressure variation.With AAO signals removed,the significant area in SH polar region shrinks obviously.AAO has a close relation with IHO in summer.4） IHO bears a close relation to synchronous surface air temperature abnormally in Asia and north of Europe in boreal autumn,spring and winter.IHO has little relationship with surface temperature.It seems plausible that diabatic heating in northern European and Asian mainland can partly explain the formation of IHO.