GENIE:Goldstein

Summary

 * Name of model: GOLDSTEIN (Global Ocean Linear Drag Salt and Temperature Equation INtegrator)


 * Authors/Constructors: Neil Edwards (OU) & Bob Marsh (NOCS)


 * Reference and description: Edwards and Marsh (2005)


 * Original version: Edwards et al. (1998); Edwards and Shepherd (2002)


 * Units: non-dimensional


 * Sign convention: positive into ocean (fluxes of heat & moisture)


 * Grid: Preferrred meshes at present are 36x36s (constant increments of sin of latitude) and 64x32 (5.625 degree resolution); 8-32 depth levels (logarithmically-spaced, maximum depth 5000 m)


 * Timestep: 100/year (36x36s); 200/year (64x32)


 * Checks to ensure continuity: total heat, freshwater in ocean ??


 * Dynamical variables: Potential temperature and Salinity anomaly (relative to 34.9 psu)

Processes modelled

 * Horizontal and vertical transport of heat, salinity anomaly, and other specified tracers (biogeochemical tracers, oxygen isotope ratio, etc.), through advection, mixing (isopycnal, diapycnal) and convection
 * Surface exchange of heat with atmosphere and sea ice, according to balance of incoming shortwave radiation, sensible and latent heat fluxes, and outgoing long-wave radiation
 * Surface exchange of moisture with atmosphere, sea ice and land, according to balance of precipitation, evaporation, runoff (at coastal gridpoints) and sea ice freezing/melting

Key parameters commonly used for tuning / model configuration

 * Horizontal (isopycnal) tracer diffusivity (Isopyc. diff.)
 * Vertical (diapycnal) tracer diffusivity (Diapyc. diff.)
 * Drag coefficient (Friction)
 * Wind scaling (Wind-scale)

Tuned values for key parameters
These are ensemble-mean values based on parameter tuning through data assimilation with the Ensemble Kalman Filter (Hargreaves et al. 2004). For further tuned parameter sets see Price et al. (2006)


 * {| border="1" cellpadding="3"

!Parameter !Value !Units
 * Isopyc. diff.
 * 4126
 * m2s-1
 * Diapyc. diff.
 * 1.81 x 10^-5
 * m2s-1
 * Friction
 * 3.43
 * days^-1
 * Wind-scale
 * 1.67
 * nondim
 * }
 * Wind-scale
 * 1.67
 * nondim
 * }
 * }

Couplings to other modules

 * Ocean-Atmosphere (EMBM or IGCM)
 * Ocean-Sea Ice (N.B. sea ice thermodynamics embedded in EMBM surface exchange scheme)

Ocean-Atmosphere I/O

 * Inputs:
 * Air temperature (deg. C)
 * Specific Humidity (g/kg)
 * Wind speed (m/s)
 * Wind stress (N/m^2)


 * Outputs:
 * Ocean surface temperature (deg. C)

Ocean-Sea Ice I/O

 * Inputs:
 * Ice fraction (nondim)
 * Ice temperature (deg. C)
 * Ice thickness (m)


 * Outputs:
 * Ocean surface temperature (deg. C)
 * Ocean surface salinity anomaly (psu)
 * Ocean surface current (m/s)

Empirical relationships
Equation of state for seawater:

density = 1000 + (0.7968*S) - (0.0559*T) - (0.0063*T^2) + (3.7315x10^-5*T^3)

which closely approximates the UNESCO formula for observed ocean density in kg m^−3 if S is in practical salinity units and T in degrees Celsius (Winton and Sarachik, 1993).