[MITgcm-devel] Re: downslope pkg

[Martin Losch]

Micheal,

please have a look at density (diagnostics variable "RHOAnoma"). This  
variable should now be zero in the ice shelf (above the ocean, this  
is required for shelfice) and non-zero in the solid ground (below the  
ocean, necessary for down_slope). Non-zero "theta" and "salt" in "dry  
cells" (hFacC=0) within the ice shelf have no effect.

Martin

On 9 Sep 2008, at 15:34, Jean-Michel Campin wrote:

> Hi Michael,
>
> I will check again that it's OK to use both pkgs, iceshelf and down- 
> slope.
> regarding "the three dimensional diagnostic",
> hFacC is the real mask, and you should not worry about any value of  
> theta
> in-land, it's just there for the algorithm to work
> (this will be fixed one day, but busy right now).
> So, do you see, e.g, non zero velocities in-land ? or other than
> theta,salt,rho fields that appear to change in-land ?
> Thanks,
> Jean-Michel
>
> PS: can you fill the subscription page to the development list:
> http://mitgcm.org/mailman/listinfo/mitgcm-devel
> so that we will just approve it.
>
> On Mon, Sep 08, 2008 at 07:27:46PM -0700, Michael Schodlok wrote:
>>
>> Hi Jean-Michel,
>>
>> first I thought the combination of packages iceshelf and down- 
>> slope was
>> running without
>> a problem as the STDOUT files didn't reveal anything abnormal.
>> But, now it seems that the mask is lost somewhere when averaging to
>> three dimensional
>> fields. While hFacC is showing land and water grid points, the three
>> dimensional diagnostic
>> fields  seem to  have only the mask of one layer (the coastline)
>> throughout the water column,
>> i.e., in case of iceshelves included, the cavities are outlined very
>> nicely.
>> Could you please check it out:
>> I've put three directories with different runs on:
>>  http://ecco2.jpl.nasa.gov/data4/MPS_output/pub/MITgcm/
>>
>>  run_ohne: without downslope and without iceshelves
>>  run_down: with downslope and without iceshelves
>>  run_ice: with downslope and with iceshelves.
>>  the directories include the data files, hFacC and THETA (first month
>> average).
>>  the model domain is 220x220x50;
>>
>>  thanks
>> Michael
>>
>>
>>> Hi Jean-Michel,
>>> the masking is absolutely necessary for the shelfice package in the
>>> current implementation (who gave this package this stoopid name,  
>>> some
>>> German idiot!), because otherwise the model integrates some  
>>> ridiculous
>>> density (for Theta=Salt=0, or even worse from some other arbitrary
>>> Theta and Salt) from the top for phiHyd. When useShelfice=.true. you
>>> are supposed to provide a reference pressure at the bottom of the  
>>> ice
>>> shelf and integrating phiHyd from the very top (k=1) is not  
>>> necessary.
>>> JMD95P and MDJFW should work with shelfice, too, for this reason.  I
>>> don't know about the downSlope package. That one was not around,  
>>> when
>>> I implemented shelfice.
>>> Without the masking, one would have to use if statements in the
>>> ij-loops for the phiHyd intergration to determine, where the real
>>> intergration of phiHyd is supposed to start; not good.  
>>> Alternatively,
>>> one could only mask alphaRho in the ice shelf, like this:
>>>         IF ( useShelfIce ) THEN
>>>          DO j=jMin,jMax
>>>           DO i=iMin,iMax
>>>            IF ( kTopC(I,J,bi,bj) .GE. k ) alphaRho(i,j) =
>>> alphaRho(i,j)*maskC(i,j,k,bi,bj)
>>>           ENDDO
>>>          ENDDO
>>>         ENDIF
>>> Do you have a better idea?
>>>
>>> Martin
>>>
>>> On 5 Sep 2008, at 18:31, Jean-Michel Campin wrote:
>>>
>>>> Hi Michael,
>>>>
>>>> I found a problem with shelfice & down_slope pkgs:
>>>> looks like useShelfIce is masking the density (in CALC_PHI_HYD)
>>>> so that we will have a problem when using an EOS directly function
>>>> of pressure (e.g.: JMD95P). I looked to
>>>> MITgcm_contrib/high_res_cube/data.hr
>>>> and it's not the case (EOS=JMD95Z).
>>>> Can you confirm that you are not using an EOS directly function
>>>> of pressure ?
>>>>
>>>> Otherwise, how is the test going ?
>>>>
>>>> I cc this to the devel list, so that Martin will know why I will
>>>> bother him to remove this masking with useShelfIce ...
>>>>
>>>> Cheers,
>>>> Jean-Michel
>>>> _______________________________________________
>>>> MITgcm-devel mailing list
>>>> MITgcm-devel at mitgcm.org
>>>> http://mitgcm.org/mailman/listinfo/mitgcm-devel
>>>
>>
>>
>> -- 
>> --
>> --
>>
>> *************************************************
>>
>> Michael Schodlok <schodlok at jpl.nasa.gov>
>> Jet Propulsion Lab/
>> California Institute of Technology
>> MS 300-323
>> 4800 Oak Grove Dr
>> Pasadena CA 91109-8099 USA
>> Tel: +1-818-354-4015  Fax: +1-818-393-6720
>>
>> *************************************************
>>
>>
>>
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