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Sea-Ice in ROMS. Kate Hedstrom, UAF Paul Budgell, Bergen Enrique Curchitser, LDEO. Outline. Equations Dynamics Thermodynamics Code cppdefs.h SeaIce directory ice.in Papers and plans. Dynamics. Momentum equations: Viscous-plastic term:. More Dynamics. Ice strength: Rearrange VP:
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Sea-Ice in ROMS Kate Hedstrom, UAF Paul Budgell, Bergen Enrique Curchitser, LDEO
Outline • Equations • Dynamics • Thermodynamics • Code • cppdefs.h • SeaIce directory • ice.in • Papers and plans
Dynamics • Momentum equations: • Viscous-plastic term:
More Dynamics • Ice strength: • Rearrange VP: • EVP version:
Solution • Stress tensor equation is timestepped explicitly • Young’s modulus E depends on ice thickness to keep solution close to VP solution • Ice velocities then timestepped with air/water stresses, Coriolis • Since it is all explicit, easy to parallelize
Thermodynamics • Need to compute all the ice growth/melt terms shown
Advection of Tracers • Advection uses MPDATA, advecting ice thickness, ice concentration, snow thickness, internal ice temperature • Followed by limiter 0 <= A <= 1
More Thermodynamics • Heat fluxes are computed through the ice and snow • Temperature is linear in the ice • FT has an oceanic log layer
ANA_ICE ICESHELF ICE_ADVECT ICE_ALB_EC92 ICE_BULK_FLUXES ICE_EVP ICE_MK ICE_MODEL ICE_MOMENTUM ICE_MOM_BULK ICE_SHOREFAST ICE_SMOLAR ICE_SMOOTH ICE_THERMO ICE_UPWIND cppdefs.h
Boundary conditions aibc.F, hibc.F, hsnbc.F, sfwatbc.F, sig11bc.F, sig12bc.F, sig22bc.F, tibc.F, uibc.F, vibc.F ice.F ice_advect.F ice_smolar.h ice_thermo.F ice_mk.h EVP rheology ice_evp.F, ice_evp_sig.F, ice_elastic.F ice_frazil.F ice_limit.F, ice_smoother.F ice_spdiw.F, ice_vbc.F SeaIce Directory
ice.in • Lice - logical for ice • dtice - same as ocean dt • nevp - number of EVP iterations per step • rhoice, rho_air, rhosnow_dry, rhoshow_wet - various densities • cdiw, cdai - drag coefficients • gamma2 - slipperiness parameter • pstar, astren - strength parameters
ice.in • zetamax, zetamin - min/max for ice viscosity • ellip_sq, alphai - ellipticity of yield curve squared • min_h, min_a, max_a - ice limiters for thickness and concentration • stressang • ice_emiss, spec_heat_air, trans_coeff, sublim_latent_heat - various thermodynamic parameters
Papers • Hunke and Dukowicz, An Elastic-Viscous-Plastic Model for Sea Ice Dynamics, JPO, 27, 1849-1867 (1997) • Hunke, Viscous-Plastic Sea Ice Dynamics with the EVP Model: Linearization Issues, JCP, 170, 18-38 (2001) • Mellor and Kantha, An Ice-Ocean Coupled Model, JGR, 94, 10,937-10,954 (1989) • Hakkinen and Mellor, Modeling the Seasonal Variability of a Coupled Arctic Ice-Ocean System, JGR, 97, 20,285-20,304 (1992)
Plans • Modeling the Bering Sea at 4 km resolution • Replacing Mellor-Kantha with CICE 3.1 (Wang and Zhang) • Multicategory and multilevel for interal ice temperatures • They need that for the Arctic