mom_ice_shelf module reference

Implements the thermodynamic aspects of ocean / ice-shelf interactions, along with a crude placeholder for a later implementation of full ice shelf dynamics, all using the MOM framework and coding style.

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Data Types

ice_shelf_cs

Control structure that contains ice shelf parameters and diagnostics handles.

Functions/Subroutines

`shelf_calc_flux()`	Calculates fluxes between the ocean and ice-shelf using the three-equations formulation (optional to use just two equations).
`adjust_ice_sheet_frazil()`	Copies frazil from the ocean surface state to the ice sheet state.
`integrate_over_ice_sheet_area()`
`ice_sheet_calving_to_ocean_sfc()`	Converts the ice-shelf-to-ocean calving and calving_hflx variables from the ice-shelf state (ISS) type to the ocean public type.
`change_thickness_using_melt()`	Changes the thickness (mass) of the ice shelf based on sub-ice-shelf melting.
`add_shelf_forces()`	This subroutine adds the mechanical forcing fields and perhaps shelf areas, based on the ice state in ice_shelf_CS.
`add_shelf_pressure()`	This subroutine adds the ice shelf pressure to the fluxes type.
`add_shelf_flux()`	Updates surface fluxes that are influenced by sub-ice-shelf melting.
`initialize_ice_shelf()`	Initializes shelf model data, parameters and diagnostics.
`initialize_ice_shelf_fluxes()`
`initialize_ice_shelf_forces()`	Allocate and initialize the ice-shelf forcing elements of a mechanical forcing type.
`initialize_shelf_mass()`	Initializes shelf mass based on three options (file, zero and user)
`change_thickness_using_precip()`	This subroutine applies net accumulation/ablation at the top surface to the dynamic ice shelf.
`update_shelf_mass()`	Updates the ice shelf mass using data from a file.
`ice_shelf_query()`	Save the ice shelf restart file.
`ice_shelf_save_restart()`	Save the ice shelf restart file.
`ice_shelf_end()`	Deallocates all memory associated with this module.
`solo_step_ice_shelf()`	This routine is for stepping a stand-alone ice shelf model without an ocean.
`process_and_post_scalar_data()`	Post_data calls for ice-sheet scalars.

Detailed Description

section_ICE_SHELF

This module implements the thermodynamic aspects of ocean/ice-shelf inter-actions using the MOM framework and coding style.

Derived from code by Chris Little, early 2010.

The ice-sheet dynamics subroutines do the following: initialize_shelf_mass - Initializes the ice shelf mass distribution. * Initializes h_shelf, h_mask, area_shelf_h

CURRENTLY: initializes mass_shelf as well, but this is unnecessary, as mass_shelf is initialized based on h_shelf and density_ice immediately afterwards. Possibly subroutine should be renamed update_shelf_mass - updates ice shelf mass via netCDF file USER_update_shelf_mass (TODO). solo_step_ice_shelf - called only in ice-only mode. shelf_calc_flux - after melt rate & fluxes are calculated, ice dynamics are done. Currently mass_shelf is updated immediately after ice_shelf_advect in fully dynamic mode.

NOTES: be aware that hmask(:,:) has a number of functions; it is used for front advancement, for subroutines in the velocity solve, and for thickness boundary conditions (this last one may be removed). in other words, interfering with its updates will have implications you might not expect.

Overall issues: Many variables need better documentation and units and the subgrid on which they are discretized.

ICE_SHELF equations

The three fundamental equations are: Heat flux

\[\qquad \rho_w C_{pw} \gamma_T (T_w - T_b) = \rho_i \dot{m} L_f\]

Salt flux

\[\qquad \rho_w \gamma_s (S_w - S_b) = \rho_i \dot{m} S_b\]

Freezing temperature

\[\qquad T_b = a S_b + b + c P\]

where ….

References

Asay-Davis, Xylar S., Stephen L. Cornford, Benjamin K. Galton-Fenzi, Rupert M. Gladstone, G. Hilmar Gudmundsson, David M. Holland, Paul R. Holland, and Daniel F. Martin. Experimental design for three interrelated marine ice sheet and ocean model intercomparison projects: MISMIP v. 3 (MISMIP+), ISOMIP v. 2 (ISOMIP+) and MISOMIP v. 1 (MISOMIP1). Geoscientific Model Development 9, no. 7 (2016): 2471.

Goldberg, D. N., et al. Investigation of land ice-ocean interaction with a fully coupled ice-ocean model: 1. Model description and behavior. Journal of Geophysical Research: Earth Surface 117.F2 (2012).

Goldberg, D. N., et al. Investigation of land ice-ocean interaction with a fully coupled ice-ocean model: 2. Sensitivity to external forcings. Journal of Geophysical Research: Earth Surface 117.F2 (2012).

Holland, David M., and Adrian Jenkins. Modeling thermodynamic ice-ocean interactions at the base of an ice shelf. Journal of Physical Oceanography 29.8 (1999): 1787-1800.

Type Documentation

type mom_ice_shelf/ice_shelf_cs