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dc.contributor.authorCounillon, Francoiseng
dc.contributor.authorBethke, Ingoeng
dc.contributor.authorKeenlyside, Noeleng
dc.contributor.authorBentsen, Matseng
dc.contributor.authorBertino, Laurenteng
dc.contributor.authorZheng, Feieng
dc.date.accessioned2015-04-10T10:34:31Z
dc.date.available2015-04-10T10:34:31Z
dc.date.issued2014-03-10eng
dc.identifier.issn0280-6495en_US
dc.identifier.urihttps://hdl.handle.net/1956/9749
dc.description.abstractHere, we firstly demonstrate the potential of an advanced flow dependent data assimilation method for performing seasonal-to-decadal prediction and secondly, reassess the use of sea surface temperature (SST) for initialisation of these forecasts. We use the Norwegian Climate Prediction Model (NorCPM), which is based on the Norwegian Earth System Model (NorESM) and uses the deterministic ensemble Kalman filter to assimilate observations. NorESM is a fully coupled system based on the Community Earth System Model version 1, which includes an ocean, an atmosphere, a sea ice and a land model. A numerically efficient coarse resolution version of NorESM is used. We employ a twin experiment methodology to provide an upper estimate of predictability in our model framework (i.e. without considering model bias) of NorCPM that assimilates synthetic monthly SST data (EnKF-SST). The accuracy of EnKF-SST is compared to an unconstrained ensemble run (FREE) and ensemble predictions made with near perfect (i.e. microscopic SST perturbation) initial conditions (PERFECT). We perform 10 cycles, each consisting of a 10-yr assimilation phase, followed by a 10-yr prediction. The results indicate that EnKF-SST improves sea level, ice concentration, 2 m atmospheric temperature, precipitation and 3-D hydrography compared to FREE. Improvements for the hydrography are largest near the surface and are retained for longer periods at depth. Benefits in salinity are retained for longer periods compared to temperature. Near-surface improvements are largest in the tropics, while improvements at intermediate depths are found in regions of large-scale currents, regions of deep convection, and at the Mediterranean Sea outflow. However, the benefits are often small compared to PERFECT, in particular, at depth suggesting that more observations should be assimilated in addition to SST. The EnKF-SST system is also tested for standard ocean circulation indices and demonstrates decadal predictability for Atlantic overturning and sub-polar gyre circulations, and heat content in the Nordic Seas. The system beats persistence forecast and shows skill for heat content in the Nordic Seas that is close to PERFECT.en_US
dc.language.isoengeng
dc.publisherCo-Action Publishingen_US
dc.rightsAttribution CC BYeng
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/eng
dc.subjectseasonal-to-decadal predictioneng
dc.subjectEnKFeng
dc.subjectNorESMeng
dc.subjectNorCPMeng
dc.subjectSST initialisationeng
dc.titleSeasonal-to-decadal predictions with the ensemble kalman filter and the Norwegian earth System Model: A twin experimenten_US
dc.typePeer reviewed
dc.typeJournal article
dc.date.updated2015-04-01T10:09:48Zen_US
dc.description.versionpublishedVersionen_US
dc.rights.holderCopyright 2014 F. Counillon et al.en_US
dc.source.articlenumber21074
dc.identifier.doihttps://doi.org/10.3402/tellusa.v66.21074
dc.identifier.cristin1162391
dc.source.journalTellus. Series A, Dynamic meteorology and oceanography
dc.source.4066
dc.relation.projectNotur: nn2993k
dc.relation.projectNorges forskningsråd: 229774
dc.subject.nsiVDP::Mathematics and natural scienses: 400::Geosciences: 450::Meteorology: 453en_US
dc.subject.nsiVDP::Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452en_US
dc.subject.nsiVDP::Matematikk og naturvitenskap: 400::Geofag: 450::Meteorologi: 453nob
dc.subject.nsiVDP::Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452nob


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