[MITgcm-support] Correct estimation of Viscosity and Diffusion parameters.

[HARRISON STEEL]

Hello everyone,
I'm working on using MITGCM to simulate a slow moving (maximum velocities
less than 1cm/second) ice covered lake. The lake is about  6 by 3 km, and
at most  150 meters deep. I've set up a coordinate system using delX=50
meters in X and Y directions, and in the Z direction I have 20 intervals,
starting from one meter thickness at the surface, and smoothly approaching
10 meters thickness at the bottom of the lake.

I am wondering, if the viscosity and diffusion parameters I have selected
are going to function correctly for this task?

viscC2smag=2.2,
 viscAz=0.001,
 viscA4=300.0,
 diffKhT=1.0e-7,
 implicitDiffusion=.TRUE.,

viscC2smag has been chosen as this was similar to values recommended in the
manual.

viscAz has been chosen as 0.001 as studied in this paper: *Sensitivity of
MITgcm to different model parameters in application to Cayuga Lake, *A.
Dorostkar,  L. Boegman, P. DIamessis, A. Pollard

viscA4 has been chosen as 300 in keeping with that in the paper: *Numerical
experiments on subaqueous melting of Greenland tidewater glaciers in
response to ocean warming and enhanced subglacial discharge*, Y. Xu, E.
RIgnot, D. Menemenlis, M. Koppes

diffKhT is again chosen as a value similar to the manual and example
problem setups.

implicitDiffusion was chosen as I believe this will take care of itself in
terms of the vertical diffusion, if what I read in the manual is correct.


I have read *Adjoint sensitivities of sub-ice-shelf melt rates to ocean
circulation under the Pine Island Ice Shelf, West Antarctica, *P. Heimbach,
M. Losch


In which the authors talk about grid-scaled velocities being implemented,
but I am unsure how exactly to go about doing this, but their vertical
viscosity is the same as mine.


Thank you in advance for any wisdom you may have regarding how these
parameters can be set to make my simulation as physically realistic as
possible.

As an aside, does anyone know if and where the Icefront package outputs ice
melt rates? In the paper on Subaqueous Greenland glacier melting they
plotted melt rates, but I haven't found this in the output files...

Regards,
Harry
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