caa a22 4500 605474788 CHVBK 20210128100349.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00382-014-2358-3 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2358-3 Effect of surface restoring on subsurface variability in a climate model during 1949-2005 [Elektronische Daten] [Sulagna Ray, Didier Swingedouw, Juliette Mignot, Eric Guilyardi] Initializing the ocean for decadal predictability studies is a challenge, as it requires reconstructing the little observed subsurface trajectory of ocean variability. In this study we explore to what extent surface nudging using well-observed sea surface temperature (SST) can reconstruct the deeper ocean variations for the 1949-2005 period. An ensemble made with a nudged version of the IPSLCM5A model and compared to ocean reanalyses and reconstructed datasets. The SST is restored to observations using a physically-based relaxation coefficient, in contrast to earlier studies, which use a much larger value. The assessment is restricted to the regions where the ocean reanalyses agree, i.e. in the upper 500m of the ocean, although this can be latitude and basin dependent. Significant reconstruction of the subsurface is achieved in specific regions, namely region of subduction in the subtropical Atlantic, below the thermocline in the equatorial Pacific and, in some cases, in the North Atlantic deep convection regions. Beyond the mean correlations, ocean integrals are used to explore the time evolution of the correlation over 20-year windows. Classical fixed depth heat content diagnostics do not exhibit any significant reconstruction between the different existing observation-based references and can therefore not be used to assess global average time-varying correlations in the nudged simulations. Using the physically based average temperature above an isotherm (14°C) alleviates this issue in the tropics and subtropics and shows significant reconstruction of these quantities in the nudged simulations for several decades. This skill is attributed to the wind stress reconstruction in the tropics, as already demonstrated in a perfect model study using the same model. Thus, we also show here the robustness of this result in an historical and observational context. Springer-Verlag Berlin Heidelberg, 2014 Decadal climate prediction nationallicence Initial conditions nationallicence Subsurface reconstruction nationallicence Surface nudging nationallicence Ray Sulagna LOCEAN/IPSL, Sorbonne Universités, UPMC-CNRS-IRD-MNHN, Case Courrier 100, 4 Place Jussieu, 75252, Paris Cedex 05, France aut Swingedouw Didier EPOC, CNRS-University of Bordeaux, Pessac, France aut Mignot Juliette LOCEAN/IPSL, Sorbonne Universités, UPMC-CNRS-IRD-MNHN, Case Courrier 100, 4 Place Jussieu, 75252, Paris Cedex 05, France aut Guilyardi Eric LOCEAN/IPSL, Sorbonne Universités, UPMC-CNRS-IRD-MNHN, Case Courrier 100, 4 Place Jussieu, 75252, Paris Cedex 05, France aut Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2333-2349 0930-7575 44:9-10<2333 2015 44 382 https://doi.org/10.1007/s00382-014-2358-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2358-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ray Sulagna LOCEAN/IPSL, Sorbonne Universités, UPMC-CNRS-IRD-MNHN, Case Courrier 100, 4 Place Jussieu, 75252, Paris Cedex 05, France aut NATIONALLICENCE 700 1- Swingedouw Didier EPOC, CNRS-University of Bordeaux, Pessac, France aut NATIONALLICENCE 700 1- Mignot Juliette LOCEAN/IPSL, Sorbonne Universités, UPMC-CNRS-IRD-MNHN, Case Courrier 100, 4 Place Jussieu, 75252, Paris Cedex 05, France aut NATIONALLICENCE 700 1- Guilyardi Eric LOCEAN/IPSL, Sorbonne Universités, UPMC-CNRS-IRD-MNHN, Case Courrier 100, 4 Place Jussieu, 75252, Paris Cedex 05, France aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2333-2349 0930-7575 44:9-10<2333 2015 44 382