论文部分内容阅读
This study presents the spatial and temporal structures of the decadal variability of the Pacific from an extended control run of a coupled global climate model (GCM).The GCM used was version-g2.0 of the Flexible Global Ocean Atmosphere Land System (FGOALS-g2.0) developed at LASG/IAP.The GCM FGOALS-g2.0 re-produces similar spatial-temporal structures of sea surface temperature (SST) as observed in the Pacific decadal os-cillation (PDO) with a significant period of approximately 14 years.Correspondingly,the PDO signals were closely related to the decadal change both in the upper-ocean temperature anomalies and in the atmospheric circulation.The present results suggest that warm SST anomalies along the equator relax the trade winds,causing the SSTs to warm even more in the eastern equatorial Pacific,which is a positive feedback.Meanwhile,warm SST anomalies along the equator force characteristic off-equa-torial wind stress curl anomalies,inducing much more poleward transport of heat,which is a negative feedback.The upper-ocean meridional heat transport,which is asso-ciated with the PDO phase transition,links the equatorial to the off-equatorial Pacific Ocean,acting as a major mechanism responsible for the tropical Pacific decadal variations.Therefore,the positive and negative feedbacks working together eventually result in the decadal oscilla-tion in the Pacific.
This study presents the spatial and temporal structures of the decadal variability of the Pacific from an extended control run of a coupled global climate model (GCM). The GCM used was version-g2.0 of the Flexible Global Ocean Atmosphere Land System (FGOALS- g2.0) developed at LASG / IAP.The GCM FGOALS-g2.0 re -sents similar spatial-temporal structures of sea surface temperature (SST) as observed in the Pacific decadal os-cillation (PDO) with a significant period of approximately 14 years. Responsively, the PDO signals were closely related to the decadal change both in the upper-ocean temperature anomalies and in the atmospheric. even more in the eastern equatorial Pacific, which is a positive feedback. Meanwhile, warm SST anomalies along the equator force characteristic off-equa-torial wind stress curl anomalies, inducing much poleward transport of heat, which is a negative feedback. The upper-ocean meridional heat transport, which is asso-ciated with the PDO phase transition, links the equatorial to the off-equatorial Pacific Ocean, acting as a major mechanism responsible for the tropical Pacific decadal variations. Beforefore, the positive and negative feedbacks working together eventually result in the decadal oscillation tion in the Pacific.