[MITgcm-support] SEAICE, very thick ice

[Yilang Xu]

Hi Stanislav, 

 

I just want to add that I have encountered this problem and Martin’s solution helped. Sea ice piling up at the boundaries will happen, when the sea ice velocity near the boundaries does not match the boundary values. 

 

You can try

#define OBCS_UVICE_OLD

#define OBCS_SEAICE_AVOID_CONVERGENCE

in OBCS_OPTION.h

 

The details of this implimentation are in obcs_adjust_uvice.F. The downside of this method is that sea ice velocity will not exactly be what has been previously prescribed. 

 

Best,

Yilang 

 

From: MITgcm-support <mitgcm-support-bounces at mitgcm.org> on behalf of Stanislav Martyanov <martyanov.sd at gmail.com>
Reply-To: <mitgcm-support at mitgcm.org>
Date: Monday, May 18, 2020 at 11:39
To: <MITgcm-support at mitgcm.org>
Subject: [MITgcm-support] SEAICE, very thick ice

 

Hello everyone!

 

I get very thick sea ice at several locations in the high-res Kara Sea model domain (horizontal resolution is 500-1200 m). Interestingly, the general pattern of sea ice concentration and thickness is OK compared to MERCATOR ocean reanalysis, but in some regions the modeled HEFF is reported by the monitor to be about 15 m after 5 months of integration (starting from realistic initial conditions). I have attached the figure to clarify what I mean and where it happens.

 

I suspect the ridging process near the open boundaries to be involved in this situation, but I do not know what can be done with it.

 

Such HEFF also produce problems in vertical layers when useRealFreshWaterFlux is TRUE, but I checked that such too thick ice is also produced when useRealFreshWaterFlux is OFF, so it is not a cause (at least, not the main cause).

 

Unfortunately, there exist too many options to just iterate through all of them.

 

May be you can advise what can be done to mitigate such overestimated HEFF? My preliminary suggestions are as follows, but I am not sure about them:

 

- to switch off the uice and vice at the OBCS?

- to set SEAICE_no_slip=TRUE to reduce the sea ice velocities near the coasts to prevent enhanced ridging?

- to use sponge at the open boundaries?

- there was a CPP key OBCS_SEAICE_AVOID_CONVERGENCE, but it is only for OBCS_UVICE_OLD which, in turn, is undefined by default and even may be not implemented, as stated.

 

Any advice is very welcome!

 

Stanislav

  

PS: I use a SEAICE package configuration which is very close to the default one. What I have changed is:

#define SEAICE_VARIABLE_SALINITY

SEAICEadvScheme = 33,

SEAICE_multDim = 1,

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