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Separate scalar diagnostics for each ice sheet + parameters to control ice-sheet velocities #714

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alex-huth
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@alex-huth alex-huth commented Aug 19, 2024

This PR adds area-integrated scalar diagnostics for ice sheets that may be requested separately for Antarctica-only (where lat<0) and/or Greenland-only (where lat>0). The previous approach, which simply integrated quantities over all ice area present in the domain, is still available for polar stereographic or idealized simulations.

This PR also adds a few ice-sheet parameters: MIN_H_SHELF, MIN_BASAL_TRACTION, MAX_SURFACE_SLOPE, and MIN_ICE_VISC. These parameters temporarily adjust the ice thickness, basal traction, surface slope, and ice viscosity, respectively, during the ice dynamics (shallow shelf approximation) solve, which helps avoid unrealistically large ice speeds (e.g. in coastal areas with very steep topography).

Also added ice-shelf surface slopes (sx_shelf, sy_shelf) as diagnostic fields

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These changes all seem reasonable to me.

…min basal traction, max surf slope, and min ice viscosity to use for ice dynamics
…yr], but converts automatically to [Pa m-1 s] in the code
…ace slope fields used in the shallow shelf approximation (SSA). This is particularly helpful for determining whether unrealistic velocities are caused by unrealistically steep surface slopes, which can sometimes arise for example, on coarse grid cells that cover both a steep mountainous region and a realively flat ice shelf. Then, the MAX_SURFACE_SLOPE parameter can be tuned to set an upper bound on the SSA surface slope to avoid these steep-slope-induced problematic velocities.
@Hallberg-NOAA Hallberg-NOAA merged commit ba59078 into NOAA-GFDL:dev/gfdl Sep 18, 2024
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2 participants