--- MITgcm_contrib/articles/ceaice/ceaice_intro.tex 2008/03/04 20:31:31 1.3 +++ MITgcm_contrib/articles/ceaice/ceaice_intro.tex 2008/06/04 13:32:49 1.5 @@ -44,25 +44,27 @@ Traditionally, probably for historical reasons and the ease of treating the Coriolis term, most standard sea-ice models are discretized on Arakawa-B-grids \citep[e.g.,][]{hibler79, harder99, - kreyscher00, zhang98, hunke97}\ml{, although there are sea ice only - models diretized on a C-grid \citep[e.g.,][]{tremblay97, - lemieux09}}. From the perspective of coupling a sea ice-model to a -C-grid ocean model, the exchange of fluxes of heat and fresh-water -pose no difficulty for a B-grid sea-ice model -\citep[e.g.,][]{timmermann02a}. However, surface stress is defined at -velocities points and thus needs to be interpolated between a B-grid -sea-ice model and a C-grid ocean model. Smoothing implicitly -associated with this interpolation may mask grid scale noise and may -contribute to stabilizing the solution. On the other hand, by -smoothing the stress signals are damped which could lead to reduced -variability of the system. By choosing a C-grid for the sea-ice model, -we circumvent this difficulty altogether and render the stress -coupling as consistent as the buoyancy coupling. + kreyscher00, zhang98, hunke97}, although there are sea ice models +diretized on a C-grid \citep[e.g.,][]{ip91, tremblay97, + lemieux09}. % +\ml{[there is also MI-IM, but I only found this as a reference: + \url{http://retro.met.no/english/r_and_d_activities/method/num_mod/MI-IM-Documentation.pdf}]} +From the perspective of coupling a sea ice-model to a C-grid ocean +model, the exchange of fluxes of heat and fresh-water pose no +difficulty for a B-grid sea-ice model \citep[e.g.,][]{timmermann02a}. +However, surface stress is defined at velocities points and thus needs +to be interpolated between a B-grid sea-ice model and a C-grid ocean +model. Smoothing implicitly associated with this interpolation may +mask grid scale noise and may contribute to stabilizing the solution. +On the other hand, by smoothing the stress signals are damped which +could lead to reduced variability of the system. By choosing a C-grid +for the sea-ice model, we circumvent this difficulty altogether and +render the stress coupling as consistent as the buoyancy coupling. A further advantage of the C-grid formulation is apparent in narrow straits. In the limit of only one grid cell between coasts there is no flux allowed for a B-grid (with no-slip lateral boundary counditions), -and models have used topographies artificially widened straits to +and models have used topographies with artificially widened straits to avoid this problem \citep{holloway07}. The C-grid formulation on the other hand allows a flux of sea-ice through narrow passages if free-slip along the boundaries is allowed. We demonstrate this effect @@ -71,11 +73,12 @@ Talk about problems that make the sea-ice-ocean code very sensitive and changes in the code that reduce these sensitivities. -This paper describes the MITgcm sea ice -model; it presents example Arctic and Antarctic results from a realistic, -eddy-permitting, global ocean and sea-ice configuration; it compares B-grid -and C-grid dynamic solvers in a regional Arctic configuration; and it presents -example results from coupled ocean and sea-ice adjoint-model integrations. +This paper describes the MITgcm sea ice model; it presents example +Arctic and Antarctic results from a realistic, eddy-permitting, global +ocean and sea-ice configuration; it compares B-grid and C-grid dynamic +solvers and investigates further aspects of sea ice modeling in a +regional Arctic configuration; and it presents example results from +coupled ocean and sea-ice adjoint-model integrations. %%% Local Variables: %%% mode: latex