Members G. Danabasoglu(co-chair) National Center for Atmospheric Research, USA

MembersG. Danabasoglu (co-chair) National Center for Atmospheric Research, USAH. Drange (co-chair) University of Bergen, NorwayM. Marsland CSIRO, AustraliaS. Griffies Geophysical Fluid Dynamics Lab., NOAA, USAG. Madec LODYC, Institute Pierre Simon Laplace, FranceR. Greatbatch Institut für Meereskunde, Kiel, GermanyH. Tsujino Met. Res. Inst., Japan Meteorological Agency, JapanE. Curchitser Rutgers University, USA

EmeritusC. Böning Institut für Meereskunde, Kiel, GermanyA. M. Treguier Laboratoire de Physique de Océans, IFREMER, FranceR. Gerdes Alfred Wegener Inst., GermanyE. Chassignet Florida State University, USA

OrganizerA. Pirani ICPO

Boulder, 23-26 Sep 2010

Sea ice/ice shelves Ocean biogeochem Ocean numerics

D. Holland (USA) K. Fennell (Canada) G. Nurser (UK)

CLIVAR Imperative IV: Improved atmosphere and ocean component models of Earth System Models

Two parallel approaches

Model development Model simulationsand analysis

Level, layer and hybrid models

Resolution & parameterizations

Numerics (accuracy, efficiency, consistency, etc.)

Test-bed for development of the ocean component in ESMs

Biogeochemistry (particularly CO2 and ocean acidificaiton) and tracers

Ice shelves (coming)

Downscaling/shelf modelling

Curchitser et. al.

Two parallel approaches

Model development Model simulationsand analysis

Level, layer and hybrid models

Resolution & parameterizations

Numerics (accuracy, efficiency, consistency, etc.)

Test-bed for development of the ocean component in ESMs

Biogeochemistry (particularly CO2 and ocean acidificaiton) and tracers

Ice shelves (coming)

Downscaling/shelf modelling

Atmospheric forcing

Spin-up procedure

Model evaluation against observations

Model comparison (but no MIP)

Analysis of interannual to decadal variability

Analysis of mechanisms

Sensitivity experiments

Main WGOMD activities(i) Workshops facilitating collaboration, communication, education - 2004 Princeton State of the Art in Ocean Climate Modelling - 2005 Hobart State of the art in Southern Ocean Modelling - 2007 Bergen Numerical Methods for Ocean Models - 2009 Exeter Ocean Mesoscale Eddies: Repr, Parameterizations, Obs - 2010 Boulder Decadal Variability, Predict, and Prediction: Role of the Ocean

(ii) Coordinated Ocean-Ice Reference Experiments (CORE I-III) - Benchmark simulations, with detailed protocols, for global ocean-ice models

(iii) Repository for Evaluating Ocean Simulations (WGOMD REOS) - Web-based tool for evaluating ocean simulations

(iv) White papers - Hurrell et al. (2009), Decadal Climate Prediction: Opportunities and Challenges, OceanObs´09 - Griffies et al. (2009), Problems and Prospects in Large-Scale Ocean Circulation Models, OceanObs´09 - Griffies et al. (2008), Sampling Physical Ocean Fields in WCRP CMIP5 Simulations

(v) Review and more specific peer-reviewed OGCM articles

CORE (Co-ordinated Ocean-Ice Reference Experiments)

Provide a workable and agreeable experimental design for global ocean-ice models to be run for long-term climate studies; should be useful for experts and newcomers

Establish a framework where the experimental design is flexible and subject to refinement as the community gains experience and provides feedback

• CORE-I Multi-century spin-up with repeating “Normal Year Forcing” (Large and Yeager, 2004; Griffies et al., 2009, Ocean Modelling)

• CORE-II: 1948-present; interannually varying forcing (Large and Yeager, 2004 & 2009)

• CORE-III Fresh water melt perturbation idealizing the melt of water around Greenland (Gerdes et al., 2006, Ocean Modelling)

• CORE IV Heat perturbation / partial coupling (being discussed)

Ongoing WGOMD synthesis work

Generate an archive of model outputAnalysis of multi-model results

Working group+ meeting, Jan 2012 in Venice

Helge DrangeGeophysical InstituteUniversity of Bergen

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Example of spin-up of OGCMs

Helge DrangeGeophysical InstituteUniversity of Bergen

Strong SSS relaxationWeak SSS relaxation + restoring

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Example of spin-up of OGCMs

1988-2007 time mean diagnostics (best forcing, ok observational support)

• Poleward heat transport: global, Atlantic, Indo-Pacific • Poleward fresh water transport: global, Atlantic, Indo-Pacific • SST, SSS, SSH, MLD (wintertime and summertime mean) • Overturning (global, Atlantic-Arctic, Indo-Pac) depth and sigma-2 space• Zonal mean temp and salinity relative to observations • Total heat flux, P-E+R entering ocean• Map of restoring/correction salt flux converted to an implied water flux • Hemispheric average annual cycle of sea ice  

Ongoing WGOMD synthesis work

Variability defined with respect to 1988-2007 mean

• Standard deviations of annual mean SST, SSS, SSH, overturning streamfunction (depth and density by basin)• MLD, summer, winter, mean, std• Tropical thermocline std (across all basins)• Tropical cells• T14C depth standard deviation• Outcropping, mean position, std• Formation, propagation, decay of T/S-anomalies• Upper ocean heat content anomaly• Thermosteric and halosteric sea level

Ongoing WGOMD synthesis work

Trends and changes

• Comparison with observed trends• Look for shifts in Atlantic and Pacific to define • The time mean minus the time mean • SST, SSS, SSH• Zonal mean temp and salinity

Case studies for

• North Atlantic • Indian Ocean• Pacific Ocean•  Southern ocean • Arctic Ocean

Ongoing WGOMD synthesis work

Illustration of sensitivities

• Changes to precip at high latitudes• Changes in zonal wind trend in Southern Ocean• Role of buoyancy and mechanical forcing for abrupt shifts• More general discussion of the role that CORE-II plays in helping feedback on the development of atmospheric states to force the ocean-ice models   

Ongoing WGOMD synthesis work

Intention to duplicate part of the analysis to the CMIP5 ensemble

Helge DrangeGeophysical InstituteUniversity of Bergen

Sensitivity experiments

Helge DrangeGeophysical InstituteUniversity of Bergen

Post 1995 forcing

Control integration (1995; “real model world”)

Lohmann et al.

EasyInit project CLIVAR meeting on decadal predictions, at KNMI, November 2009: 

modeling community had suggested and requested that ocean reanalysis are being provided in an “EasyInit” project that can

support the coupled modeling community to ease the initialization of decadal prediction runs using ocean reanalyses

 Aim: The modeling community can get all reanalysis in a “one-stop” fashion and with a uniform format Host: The KlimaCampus of the University of Hamburg (D. Stammer)

* http://www.clisap.de/Easy-INIT.easyinit.0.html* presently 8 (?) reanalyses are (more or less) available for comparison and analysis