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dc.contributor.authorLuo, Hao
dc.contributor.authorZheng, Fei
dc.contributor.authorKeenlyside, Noel
dc.contributor.authorZhu, Jiang
dc.date.accessioned2022-02-07T08:08:52Z
dc.date.available2022-02-07T08:08:52Z
dc.date.created2020-12-07T01:49:28Z
dc.date.issued2020
dc.identifier.issn0930-7575
dc.identifier.urihttps://hdl.handle.net/11250/2977364
dc.description.abstractCurrently, the mechanisms for Pacific Decadal Oscillation (PDO) are still disputed, and in particular the atmosphere response to the ocean in the mid-latitude remains a key uncertainty. In this study, we investigate two potential feedbacks—a local positive and a delayed negative—for the PDO based on a long-term control simulation using the ECHAM5/MPI-OM coupled model, which is selected because of reproduces well the variability of PDO. The positive feedback is as follows. In the PDO positive phase, the meridional sea surface temperature (SST) gradient is intensified and this strengthens the lower level atmospheric baroclinicity in the mid-latitudes, leading to the enhancement of Aleutian low and zonal wind. These atmospheric changes reinforce the meridional SST temperature gradient through the divergence of ocean surface currents. The increased heat flux loss over the anomalously warm water and decreased heat flux loss over the anomalously cold water in turn reinforce the lower atmospheric meridional temperature gradient, baroclinicity and atmospheric circulation anomalies, forming a local positive feedback for the PDO. The delayed negative feedback arises, because the intensified meridional SST gradient also generates an anticyclonic wind stress in the central North Pacific, warming the upper ocean by Ekman convergence. The warm upper ocean anomalies then propagate westward and are transported to the mid-latitudes in the western North Pacific by the western boundary current. This finally reduces the meridional SST gradient, 18 years after the peak PDO phase. These results demonstrate the significant contributions of the meridional SST gradient to the PDO’s evolution.en_US
dc.language.isoengen_US
dc.publisherSpringeren_US
dc.titleOcean–atmosphere coupled Pacific Decadal variability simulated by a climate modelen_US
dc.typeJournal articleen_US
dc.typePeer revieweden_US
dc.description.versionacceptedVersionen_US
dc.rights.holderCopyright Springer-Verlag GmbH Germany, part of Springer Nature 2020en_US
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.fulltextpostprint
cristin.qualitycode2
dc.identifier.doi10.1007/s00382-020-05248-9
dc.identifier.cristin1856657
dc.source.journalClimate Dynamicsen_US
dc.source.pagenumber4759-4773en_US
dc.relation.projectNotur/NorStore: NS9039Ken_US
dc.relation.projectNotur/NorStore: nn9039Ken_US
dc.relation.projectTrond Mohn stiftelse: BFS2018TMT01en_US
dc.relation.projectEC/H2020/648982en_US
dc.identifier.citationClimate Dynamics. 2020, 54, 4759-4773.en_US
dc.source.volume54en_US


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