GENIE:Seaice

Summary

 * Name of model: GOLDSTEIN Sea Ice


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


 * Reference and description: Edwards and Marsh (2005)


 * Original version: Part of UVic Earth System Model (Weaver et al. 2001)


 * Units: SI & non-dimensional


 * Sign convention: positive into sea ice (fluxes of heat & freshwater)


 * Grid: As ocean (preferrred meshes at present are 36x36s and 64x32)


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


 * Checks to ensure continuity: n/a ??


 * Dynamical variables: Sea ice concentration and thickness

Processes modelled

 * Horizontal transport of sea ice concentration and thickness
 * Surface exchange of heat with atmosphere, according to balance of incoming shortwave radiation, sensible and latent heat fluxes, and outgoing long-wave radiation
 * Surface exchange of heat with ocean, according to balance of sensible and latent heat fluxes (freezing/melting)
 * Surface exchange of freshwater with atmosphere, according to balance of precipitation and evaporation/sublimation
 * Surface exchange of freshwater with ocean, according to balance of freezing and melting

Key parameters commonly used for tuning / model configuration

 * Sea ice diffusivity (sea ice diff.), of concentration and thickness
 * EVP parameters (optional) - details soon

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)


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!Parameter !Value !Units
 * Sea Ice diff.
 * 6249
 * m2s-1
 * }
 * }
 * }

Common Runtime Settings

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!Parameter !Value !Comment
 * yearlen
 * 365.25
 * days/year
 * nyear
 * 100
 * timesteps/year
 * npstp
 * 1000
 * healthcheck written every N timesteps
 * iwstp
 * 50000
 * restart written every N timesteps
 * itstp
 * 100
 * integral diagnostics written every N timesteps
 * ianav
 * 50000
 * output averaged over N timesteps
 * }
 * integral diagnostics written every N timesteps
 * ianav
 * 50000
 * output averaged over N timesteps
 * }
 * }

Couplings to other modules

 * Ocean-Sea Ice-Atmosphere (N.B. 2-way coupling to solve iteratively for sea ice temperature)

Ocean-Sea Ice-Atmosphere I/O

 * Inputs:
 * Air temperature (deg. C)
 * Specific humidity (g/kg)
 * Shortwave radiation (W/m^2)
 * Surface ocean temperature (deg. C)
 * Surface ocean salinity anomaly (psu), for freezing point of seawater
 * Surface ocean current (m/s)


 * Outputs:
 * Sea Ice concetration (fraction, 0-1)
 * Sea Ice thickness (m)
 * Sea Ice temperature (deg. C)

Prescribed inputs

 * none

Empirical relationships
Freezing point for seawater:

T_freeze =

where S is in practical salinity units and T in degrees Celsius (REF).