热带海洋学报JOURNALOFTROPICALOCEANOGRAPHY2023年第42卷第4期:36–46doi:10.11978/2022189http://www.jto.ac.cnPDO对ENSO非对称性的年代际调整及其机制①李承勇,孟祥凤,谢瑞煌中国海洋大学海洋与大气学院,山东青岛266100摘要:本文利用HadISST的月平均海温数据以及ORAS3再分析数据,研究了PDO(PacificDecadalOscillation)不同位相对ENSO(ElNiñoandSouthOscillation)非对称的年代际调整。对PDO不同位相的海表温度异常(SSTA,seasurfacetemperatureanomaly)的偏度分析发现,PDO正位相期间东太平洋的ENSO非对称明显强于PDO负位相期间。同时,通过对次表层(50~150m)海洋热量收支计算发现,东太平洋次表层非线性动力加热项(NDH,nonlineardynamicalheating)在PDO不同位相下也有明显的变化,PDO正位相期间东太平洋的次表层NDH明显强于PDO负位相期间,NDH的差异主要是由其纬向分量NDHx的差异引起的。东太平洋更强的次表层NDHx使PDO正位相期间ElNiño事件和LaNiña事件次表层温度异常(SubTA,subsurfacetemperatureanomaly)的差距更大,从而引起SSTA的非对称,导致PDO正位相期间东太平洋的ENSO非对称比PDO负位相期间强。关键词:ENSO非对称;PDO;热收支分析;非线性动力加热项;次表层中图分类号:P731.11文献标识码:A文章编号:1009-5470(2023)04-0036-11InterdecadalmodulationofENSOasymmetrybythePacificDecadalOscillationanditsmechanismLIChengyong,MENGXiangfeng,XIERuihuangCollegeofOceanicandAtmosphericSciences,OceanUniversityofChina,Qingdao266100,ChinaAbstract:ElNiñoandSouthOscillation(ENSO)asymmetrybetweenElNiñoandLaNiñaeventsinthepositiveandnegativePacificDecadalOscillation(PDO)phasesisexaminedusingHadISSTandORAS3oceanreanalysisproducts.ItisfoundthatENSOasymmetryintheequatorialeasternPacificissignificantlyweakerinthenegativePDOphasethanthatinthepositivePDOphase.ItisfoundthattheeasternPacific'ssubsurfacenonlineardynamicalheating(NDH)islikewisegreatlyaffectedbythevariousPDOphases,anditismuchstrongerduringthePDOpositivephasethanthatduringthePDOnegativephasethroughheatbudgetanalysisoftheoceansubsurfacelayer.ThesubsurfaceNDHislargelycontributedbyNDHx.AlargergapbetweentheElNiñoeventandtheLaNiñaeventSubsurfaceTemperatureAnomaly(SubTA)duringthepositivephaseofthePDOiscausedbythestronger...
