a coupled ice-ocean model based on roms/toms 2.0 w. paul budgell institute of marine research and...
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A Coupled Ice-Ocean Model Based on ROMS/TOMS 2.0
W. Paul Budgell
Institute of Marine Researchand
Bjerknes Centre for Climate ResearchBergen, Norway
Terrain-Following ModelUser’s Group Meeting
Seattle, August 4-6, 2003
IMR
IMR
Outline of Talk:
• Description of ice model
• Coupling of ice model to ROMS
• Basin-scale coupled ice-ocean model
• To do
IMR
Outline of Talk:
• Description of ice model
• Coupling of ice model to ROMS
• Basin-scale coupled ice-ocean model
• To do
IMR
Ice Dynamics
Ice dynamics are based upon the elastic-viscous-plastic (EVP)rheology of Hunke and Dukowicz (1997), Hunke (1991) and Hunke and Dukowicz (1992).
Under low deformation (rigid behaviour), the singularity is regularized by elastic waves. The response is very similar toviscous-plastic models in typical Arctic pack ice conditions.
Numerical behaviour improved significantly by applyinglinearization of the viscosities at every EVP time step.
The EVP model parallelizes very efficiently under both OpenMPAnd MPI.
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Ice Thermodynamics
Ice thermodynamics are based upon those of Mellor andKantha (1989) and Häkkinen and Mellor (1992). Main featuresinclude:• Three-level, single layer ice; single snow layer• Molecular sublayer under ice; Prandtl-type ice-ocean boundary layer• Surface melt ponds• Forcing by short and long-wave radiation, sensible and latent heat flux• NCEP fluxes, corrected for model surface temperature and ice concentration, used as forcing
IMR
Outline of Talk:
• Description of ice model
• Coupling of ice model to ROMS
• Basin-scale coupled ice-ocean model
• To do
IMR
Coupling of Ice Model to ROMS
Tried to keep things modular:
In main3d.F: ice routines NCEP flux routines
CALL ice_albedo (ng,tile) CALL cawdir_eval (ng,tile) CALL ncep_flux (ng, tile) CALL ice (ng)
CALL ice_frazil(ng,tile)
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Coupling of Ice Model to ROMS
New ice variables stored in mod_ice.F
Ice model contained in ice.F:• computes ice-ocean fluxes• performs EVP dynamics• performs advection of all ice/snow prognostic variables• performs ice/snow thermodynamics
ice_frazil.F:• checks for water masses below freezing point• computes ice growth mass flux from frazil ice formation• adjusts T and S for ice formation
IMR
Outline of Talk:
• Description of ice model
• Coupling of ice model to ROMS
• Basin-scale coupled ice-ocean model
• To do
IMR
Transformed Spherical Grid
Surface Temperature (deg C) 1949/03/06
Sea Surface Height (m) 1949/03/06
Ice Concentration (1949/03/06)
Ice Concentration (1949/03/06)
Ice Concentration (1949/09/30)
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Simulated Sea Ice Thickness 1949
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Simulated Sea Ice Thickness 1949
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Simulated Sea Ice Thickness 1949
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Simulated Sea Ice Thickness 1949
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Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Simulated Sea Ice Thickness 1949
IMR
Outline of Talk:
• Description of ice model
• Coupling of ice model to ROMS
• Basin-scale coupled ice-ocean model
• To do
IMR
Work in Progress
• Clean up the code
• Fix small parallelization inconsistency
• Developed idealized test cases for analytical.F• ICE_BASIN• ICE_OCEAN_1D
• Modify bulk_flux.F to take ice forcing
• Implement open BC FRS scheme for ice variables (B. Ådlandsvik)
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Work in Progress/Future Work
• Implementation on a 4-km grid for the Barents region
• Run AOMIP
• Implement full metric terms for curvilinear grid (Hunke and Dukowicz, 2002)
• Multiple ice thickness categories, energy conservation (NCAR, CICE, Bitz and Lipscomb (1999))
• Couple high-resolution ice-ocean ROMS to mesoscale atmospheric model MM5 (Polar)