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Reconstructing the subsurface ocean decadal variability using surface nudging in a perfect model framework

dc.rights.licenseopenen_US
hal.structure.identifierLaboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
hal.structure.identifierModelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics [MERMAID]
dc.contributor.authorSERVONNAT, Jérôme
hal.structure.identifierProcessus de la variabilité climatique tropicale et impacts [PARVATI]
dc.contributor.authorMIGNOT, Juliette
hal.structure.identifierProcessus de la variabilité climatique tropicale et impacts [PARVATI]
dc.contributor.authorGUILYARDI, Éric
hal.structure.identifierLaboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorSWINGEDOUW, Didier
hal.structure.identifierLaboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
hal.structure.identifierCentre national de recherches météorologiques [CNRM]
dc.contributor.authorSÉFÉRIAN, Roland
hal.structure.identifierCentre national de recherches météorologiques [CNRM]
dc.contributor.authorLABETOULLE, Sonia
dc.date.accessioned2024-06-07T12:31:30Z
dc.date.available2024-06-07T12:31:30Z
dc.date.issued2015-01
dc.identifier.issn0930-7575en_US
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/200342
dc.description.abstractEnInitialising the ocean internal variability for decadal predictability studies is a new area of research and a variety of ad hoc methods are currently proposed. In this study, we explore how nudging with sea surface temperature (SST) and salinity (SSS) can reconstruct the three-dimensional variability of the ocean in a perfect model framework. This approach builds on the hypothesis that oceanic processes themselves will transport the surface information into the ocean interior as seen in ocean-only simulations. Five nudged simulations are designed to reconstruct a 150 years “target” simulation, defined as a portion of a long control simulation. The nudged simulations differ by the variables restored to, SST or SST + SSS, and by the area where the nudging is applied. The strength of the heat flux feedback is diagnosed from observations and the restoring coefficients for SSS use the same time-scale. We observed that this choice prevents spurious convection at high latitudes and near sea-ice border when nudging both SST and SSS. In the tropics, nudging the SST is enough to reconstruct the tropical atmosphere circulation and the associated dynamical and thermodynamical impacts on the underlying ocean. In the tropical Pacific Ocean, the profiles for temperature show a significant correlation from the surface down to 2,000 m, due to dynamical adjustment of the isopycnals. At mid-to-high latitudes, SSS nudging is required to reconstruct both the temperature and the salinity below the seasonal thermocline. This is particularly true in the North Atlantic where adding SSS nudging enables to reconstruct the deep convection regions of the target. By initiating a previously documented 20-year cycle of the model, the SST + SSS nudging is also able to reproduce most of the AMOC variations, a key source of decadal predictability. Reconstruction at depth does not significantly improve with amount of time spent nudging and the efficiency of the surface nudging rather depends on the period/events considered. The joint SST + SSS nudging applied everywhere is the most efficient approach. It ensures that the right water masses are formed at the right surface density, the subsequent circulation, subduction and deep convection further transporting them at depth. The results of this study underline the potential key role of SSS for decadal predictability and further make the case for sustained large-scale observations of this field.
dc.language.isoENen_US
dc.title.enReconstructing the subsurface ocean decadal variability using surface nudging in a perfect model framework
dc.typeArticle de revueen_US
dc.identifier.doi10.1007/s00382-014-2184-7en_US
dc.subject.halPhysique [physics]/Physique [physics]/Géophysique [physics.geo-ph]en_US
bordeaux.journalClimate Dynamicsen_US
bordeaux.page315-338en_US
bordeaux.volume44en_US
bordeaux.hal.laboratoriesEPOC : Environnements et Paléoenvironnements Océaniques et Continentaux - UMR 5805en_US
bordeaux.issue1-2en_US
bordeaux.institutionUniversité de Bordeauxen_US
bordeaux.institutionCNRSen_US
bordeaux.teamPALEOen_US
bordeaux.peerReviewedouien_US
bordeaux.inpressnonen_US
bordeaux.import.sourcehal
hal.identifierhal-01135684
hal.version1
hal.popularnonen_US
hal.audienceInternationaleen_US
hal.exportfalse
workflow.import.sourcehal
dc.rights.ccPas de Licence CCen_US
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Climate%20Dynamics&rft.date=2015-01&rft.volume=44&rft.issue=1-2&rft.spage=315-338&rft.epage=315-338&rft.eissn=0930-7575&rft.issn=0930-7575&rft.au=SERVONNAT,%20J%C3%A9r%C3%B4me&MIGNOT,%20Juliette&GUILYARDI,%20%C3%89ric&SWINGEDOUW,%20Didier&S%C3%89F%C3%89RIAN,%20Roland&rft.genre=article


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