[MITgcm-devel] another bug in growth.F ?

[Jinlun Zhang]

Hold, Dimitris. I need to check the code again to make sure I remember 
things. I have been using a different model for ages, need to fresh my 
memory.
Jinlun

Dimitris Menemenlis wrote:

>> It is actual thickness, so it is AREA*HSNOW.
>
>
> Arghh!!!  There is (at least) 3 places in code where HSNOW is used as 
> effective snow thickness:
>
> 1. in growth.F, when FREEZING PRECIP is added as snow:
>
>>            HSNOW(I,J,bi,bj)=HSNOW(I,J,bi,bj)+SEAICE_deltaTtherm*
>>      &            PRECIP(I,J,bi,bj)*AR(I,J,bi,bj)*SDF
>
>
> 2. in growth.F, the latest HSNOW fix:
>
>>           IF(RESID_HEAT(I,J,bi,bj).GT.ZERO.AND.
>>      &         HSNOW(I,J,bi,bj).GT.ZERO) THEN
>>            GHEFF(I,J)=MIN(HSNOW(I,J,bi,bj)/SDF/ICE_DENS,
>>      &         RESID_HEAT(I,J,bi,bj))
>>            YNEG(I,J,bi,bj)=YNEG(I,J,bi,bj)+GHEFF(I,J)
>>            HSNOW(I,J,bi,bj)=HSNOW(I,J,bi,bj)-GHEFF(I,J)*SDF*ICE_DENS
>>            SEAICE_SALT(I,J,bi,bj)=SEAICE_SALT(I,J,bi,bj)-GHEFF(I,J)
>>           ENDIF
>
>
> 3. in seaice_advdiff.F, the advection of snow:
>
>>         DO j=1-Oly,sNy+Oly
>>          DO i=1-Olx,sNx+Olx
>>           iceFld(i,j) = HSNOW(i,j,bi,bj)
>>          ENDDO
>>         ENDDO
>>         CALL SEAICE_ADVECTION(
>>      I       GAD_SNOW, SEAICEadvSchSnow, .TRUE.,
>>      I       uc(1-OLx,1-OLy,bi,bj), vc(1-OLx,1-OLy,bi,bj),
>>      I       uTrans, vTrans, iceFld, recip_heff,
>>      O       gFld, afx, afy,
>>      I       bi, bj, myTime, myIter, myThid )
>
>
> Item number 2 above, is very likely responsible for the high tangent 
> linear sensitivities that Patrick reported.  I will try to rewrite 
> everything in terms of effective snow thickness ... I think it's path 
> of least resistance at this point.  D.
> _______________________________________________
> MITgcm-devel mailing list
> MITgcm-devel at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-devel


-- 

Jinlun Zhang
Polar Science Center, Applied Physics Laboratory
University of Washington, 1013 NE 40th St, Seattle, WA 98105-6698

Phone: (206)-543-5569;  Fax: (206)-616-3142
zhang at apl.washington.edu
http://psc.apl.washington.edu/pscweb2002/Staff/zhang/zhang.html