Table 3: Selected Features of CMIP Oceanic Models 

Horizontal/vertical resolution, vertical coordinates, dynamical framework, and the formulations of horizontal and vertical mixing used in the oceanic components of the CMIP coupled models. Links at the head of table columns connect to further explanations of information in that column.
 
 
CMIP Model Ocean Resolution Vertical Coordinate Dynamics Horizontal Eddy Mixing  Vertical Eddy Mixing 
BMRC1 3.2x5.6 L12  Z PE/R V=9x105, D=2.5x103: Power et al.(1993) V=D=1 to 20 x 10-4: Power et al.(1993)
CCCma 1.8x1.8 L29  Z PE/R V=1.4x105, D=2x103 V=2x10-3, D=3x10-5
CCSR 2.8x2.8 L17 Z PE/R V=2x105 , D=1x103 V=D=2 x 10-3
CERFACS1  2.0x2.0 L31** Z PE/R V=0.2 to 4x104, D=2x103: Guilyardi&Madec(1997) Blanke&Delecluse(1993)
COLA 1 1.5x1.5 L20* Z PE/R V=D=2x103 Pacanowski&Philander(1981)
COLA 2 3.0x3.0 L20* Z PE/R V=1x105, D=4x103 Pacanowski&Philander(1981)
CSIRO  3.2x5.6 L21  Z PE/R  V=9x105; 
Isopycnal tracer D=1x104; Isopycnal thickness D=1x104:  Hirst et al.(2000)		 V=20 x 10-4; D=Variable: Hirst et al.(2000)
ECHAM1+LSG 4.0x4.0 L11 Z PE*/F V=D=2x102 No eddy mixing
ECHAM3+LSG 4.0x4.0 L11 Z PE*/F V=D=2x102 No eddy mixing
ECHAM4+OPYC3 2.8x2.8 L11* RHO PE/F Isopycnal V,D ~ 1x103 to 1x104: Oberhuber(1993) Cross-isopycnal mixing: Oberhuber(1993)
ECHAM4+HOPE-G 2.8x2.8 L20* Z PE/F V(harmonic=150)+V(biharmonic=1x10-3*(dx**4/dt))+ 
V(local strain rate dependent)
D(harmonic=1.5x103)+D (local strain rate dependent)
both with 'eddy' memory :Legutke and Maier- Reimer(1999)		 Pacanowski&Philander(1981),with 'eddy' memory enhanced m.l. mixing for unstable surface:
Legutke and Maier-Reimer(1999)
GFDL_R15_a 4.5x3.7 L12 Z PE/R V=2.5x105; D=7.5x102+isopycnal D(Z): Manabe et al.(1991), Redi(1982) V=5x10-3; isopycnal D(Z): Bryan&Lewis(1979) with crossover at 2.5 km depth; at sfc: 0.3 x 10-4, at bottom: 1.3 x 10-4
GISS (Miller)  4.0x5.0 L16  Z PE/R V=4x105; D(Z): Bryan&Lewis(1979) V=2x10-3 ; D(Z): Bryan&Lewis(1979)
GISS (Russell)  4.0x5.0 L13*** M PEC/F V=D=0: Russell et al.(1995) Russell et al.(1995)
IAP/LASG1 4.0x5.0 L20 ETA PE/F V= 8x105, D=2x103: Zhang et al.(1996), Yu(1997) V=1x10-4, D=3x10-5
LMD/IPSL1 2.0x2.0 L31** Z PE/R V=1 to 16x104, D=2x103: Braconnot et al.(1997) Blanke&Delecluse(1993)
MRI1 2.0x2.5 L21* Z PE/R Max V=2x105, D=5x103: Tokioka et al.(1996) Mellor&Yamada(1974,1982), 
Mellor&Durbin(1975)
NCAR (CSM) 2.0x2.4 L45* Z PE/R V=8x104, D=8x102: Gent&McWilliams(1990) Large et al.(1994), no convective adjustment
NRL1 1.0x2.0 L25* Z PE/F V=2x103, D=1x103 Pacanowski&Philander(1981)
UKMO (HadCM2) 2.5x3.75 L20 Z PE/R V=1.5 to 3x105; D=40+isopycnal D(Z): Johns et al.(1997), Redi(1982) Johns et al.(1997), Pacanowski&Philander(1981)

Ocean Resolution: Horizontal and vertical resolution.   The former is expressed as degrees latitude x longitude, while the latter is expressed as "Lmm", where mm is the number of vertical levels.  A * signifies enhanced horizontal resolution near the Equator, while ** indicates that the CMIP data are interpolated to a coarser grid than that of the original model data.  The designation *** indicates that three directional gradients for heat and salt are calculated in each grid box, which effectively enhances the resolution.

Vertical Coordinate: Z denotes that the vertical coordinate is depth, P that it is pressure, M that it is mass per unit area (~ pressure under constant gravity), ETA that it is a topography-weighted depth (cf. Mesinger and Janjic 1975), and RHO that it is density (i.e., isopycnal coordinates).

Dynamics: PE denotes use of the primitive equations (including the assumption of incompressibility and of hydrostatic and Boussinesq approximations); application of the primitive equations, but with neglect of momentum advection, is indicated by PE*, while use of the primitive equations, but with compressible flow and without the Boussinesq approximation, is denoted by PEC. R indicatesthat the dynamical equations are solved assuming a "rigid-lid" upper boundary condition, while F implies the assumption of a "free surface" condition.

Horizontal Eddy Mixing: The parameterization of horizontal mixing by sub-gridscale eddies, where V denotes the horizontal viscosity coefficient (i.e., horizontal mixing of momentum) and D denotes the horizontal diffusivity coefficient (i.e., horizontal mixing of heat and/or salinity); both V and D are expressed in units of m2 s-1. (In many ocean models, V is set to an artificially high value for numerical reasons. V and/or D set to zero implies the use of alternative means of ensuring satisfactory horizontal mixing, such as application of an upstream advective scheme.) As appropriate, a suitable reference is cited for further details.

Vertical Eddy Mixing: The parameterization of vertical mixing by sub-gridscale eddies, where V denotes the vertical viscosity coefficient (i.e., vertical mixing of momentum) and D denotes the vertical diffusivity coefficient (i.e., vertical mixing of heat and/or salinity); both V and D are expressed in units of m2 s-1. Where a more complex parameterization than linear diffusion with constant diffusivity is employed, a suitable reference is cited. Note also that, in addition to eddy diffusion, ocean models may utilize convective adjustment and/or explicit mixed layer schemes as mechanisms for vertical mixing.
 
 

References

Blanke, B., and P. Delecluse, 1993: Low frequency variability of the tropical Atlantic ocean simulated by a general circulation model with mixed layer physics. J. Phys. Oceanogr., 23, 1363-1388.

Braconnot, P., O. Marti, and S. Joussaume, 1997: Adjustment and feedbacks in a global coupled ocean-atmosphere model. Climate Dyn., 13, 507-519.

Bryan, K., and L.J. Lewis, 1979: A water mass model of the world ocean. J. Geophys. Res., 84(C5), 2503-2517.

Gent, P.R., and J.C. McWilliams, 1990: Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr., 20, 150-155.

Guilyardi, E., and G. Madec, 1997: Performance of the OPA/ARPEGE-T21 global ocean-atmosphere coupled model. Climate Dyn., 13, 149-165.

Hirst, A.C., S.P. O'Farrell, And H.B. Gordon, 2000: Comparison of a coupled ocean-atmosphere model with and without oceanic eddy-induced advection. 1. Ocean spin-up and control integrations. J. Climate, 13, 139-163.

Johns, T.C., R.E. Carnell, J.F. Crossley, J.M. Gregory, J.F.B. Mitchell, C.A. Senior, S.F.B. Tett, and R.A. Wood, 1997: The second Hadley Centre coupled ocean-atmosphere GCM: Model description, spinup and validation. Climate Dyn., 13, 103-134.

Large, W.G., J.C. McWilliams, and S.C. Doney, 1994: Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Rev. of Geophys., 32, 363-403.

Legutke, S. and E. Maier-Reimer, 1999: Climatology of the HOPE-G Global Ocean General Circulation Model. Technical report, No. 21, German Climate Computing Centre (DKRZ), Hamburg, 90 pp.

Manabe, S., R.J. Stouffer, M.J. Spelman, and K. Bryan, 1991: Transient responses of a coupled ocean-atmosphere model to gradual changes of atmospheric CO2. Part I: Annual mean response. J. Climate, 4, 785-818.

Mellor, G.L., and P.A. Durbin, 1975: The structure and dynamics of the ocean surface mixed layer. J. Phys. Oceanogr., 5, 718-728.

Mellor, G.L., and T. Yamada, 1974: A hierarchy of turbulence closure models for planetary boundary layers. J. Atmos. Sci., 31, 1791-1806.

Mellor, G.L., and T. Yamada, 1982: Development of a turbulence closure model for geophysical fluid problems. Rev. Geophys. Space Phys., 20, 851-875.

Mesinger, F., and Z.I. Janjic, 1975:Problems and numerical methods of the incorporation of mountains in atmospheric models. Lectures in Applied Mathematics, 22, 81-120.

Moore, A.M., and C. J.C. Reason, 1993: The response of a global ocean general circulation model to climatological surface boundary conditions for temperature and salinity. J. Phys. Oceanog., 23, 300-328.

Oberhuber, J. M., 1993: Simulation of the Atlantic circulation with a coupled sea-ice-mixed layer-isopycnical general circulation model. Part I: model description. J. Phys. Oceanogr., 23, 808-829.

Pacanowski, R., and S.G.H. Philander, 1981: Parameterization of vertical mixing in numerical models of tropical oceans. J. Phys. Oceanogr., 11, 1443-1451.

Power, S.B., R.A. Colman, B.J. McAvaney, R.R. Dahni, A.M. Moore, and N.R. Smith, 1993: The BMRC Coupled atmosphere/ocean/sea-ice model. BMRC Research Report No. 37, Bureau of Meteorology Research Centre, Melbourne, Australia, 58 pp

Redi, M.H., 1982: Oceanic isopycnal mixing by coordinate rotation. J. Phys. Oceanogr., 12, 1154-1158.

Russell, G.L., J.R. Miller, and D. Rind, 1995: A coupled atmosphere-ocean model for transient climate change studies. Atmos.-Ocean, 33, 683-730.

Tokioka, T., A. Noda, A. Kitoh, Y. Nikaidou, S. Nakagawa, T. Motoi, S. Yukimoto, and K. Takata, 1996: A transient CO2 experiment with the MRI CGCM: Annual mean response. CGER's Supercomputer Monograph Report Vol. 2, CGER-IO22-96, ISSN 1341-4356, Center for Global Environmntal Research, National Institute for Environmental Studies, Environment Agency of Japan, Ibaraki, Japan, 86 pp.

Yu, Y.-Q., 1997: Design of a sea-air-ice coupling scheme and a study of numerical simulation of interdecadal oscillation of climate. Ph.D. thesis, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China, 130 pp. (in Chinese).

Zhang, X.-H., K.-M. Chen, Z.-Z. Jin, W.-Y. Lin, and Y.-Q. Yu, 1996: Simulation of thermohaline circulation with a twenty-layer oceanic general circulation model. Theoretical and Applied Climatology, 55, 65-88.
 

















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