[MITgcm-devel] Re: downslope pkg

[Michael Schodlok]

 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
>


-- 
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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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