[MITgcm-support] Turbulent Ice-Ocean heat flux

[Alexander Slavin]

Martin,

Thank you for quick answer. Good remark about versions.
I used one year old version - v 1.140 2011/07/21
In new 1.173 version this part of code in seaice_growth.F looks like:

C determine available heat due to the ice pack tying the
C underlying surface water temperature to freezing point
C ======================================================

#ifdef ALLOW_AUTODIFF_TAMC
CADJ STORE theta(:,:,kSurface,bi,bj) = comlev1_bibj,
CADJ &                       key = iicekey, byte = isbyte
CADJ STORE salt(:,:,kSurface,bi,bj) = comlev1_bibj,
CADJ &                       key = iicekey, byte = isbyte
#endif

         DO J=1,sNy
          DO I=1,sNx
C         FREEZING TEMP. OF SEA WATER (deg C)
           tempFrz = SEAICE_tempFrz0 +
&              SEAICE_dTempFrz_dS *salt(I,J,kSurface,bi,bj)
C efficiency of turbulent fluxes : dependency to sign of THETA-TBC
           IF ( theta(I,J,kSurface,bi,bj) .GE. tempFrz ) THEN
            tmpscal1 = SEAICE_mcPheePiston
           ELSE
            tmpscal1 =SEAICE_frazilFrac*drF(kSurface)/SEAICE_deltaTtherm
           ENDIF
C efficiency of turbulent fluxes : dependency to AREA (McPhee cases)
           IF ( (AREApreTH(I,J) .GT. 0. _d 0).AND.
&         (.NOT.SEAICE_mcPheeStepFunc) ) THEN
            MixedLayerTurbulenceFactor = ONE -
&          SEAICE_mcPheeTaper * AREApreTH(I,J)
           ELSEIF ( (AREApreTH(I,J) .GT. 0. _d 0).AND.
&             (SEAICE_mcPheeStepFunc) ) THEN
            MixedLayerTurbulenceFactor = ONE - SEAICE_mcPheeTaper
           ELSE
            MixedLayerTurbulenceFactor = ONE
           ENDIF
C maximum turbulent flux, in ice meters
           tmpscal2= - (HeatCapacity_Cp*rhoConst * recip_QI)
&         * (theta(I,J,kSurface,bi,bj)-tempFrz)
&         * SEAICE_deltaTtherm * maskC(i,j,kSurface,bi,bj)
C available turbulent flux
           a_QbyOCN(i,j) =
&         tmpscal1 * tmpscal2 * MixedLayerTurbulenceFactor
           r_QbyOCN(i,j) = a_QbyOCN(i,j)
          ENDDO
         ENDDO

But it is still not clear for me, where the dependence of relative 
ocean-ice velocity calculated?
Is it in SEAICE_mcPheePiston constant?

Thank you,

Alexander.


On 08/01/2012 04:47 AM, Martin Losch wrote:
> Alexander, which version of the code do you use (at the top of seaice_growth.F you'll find the Header-line, the most recent version is v 1.173)?
>
> Martin
> On Jul 31, 2012, at 6:49 PM, Alexander Slavin wrote:
>
>> Hello MITgcm users,
>>
>> I have a question concerning turbulent Ice-Ocean heat flux.
>> Do MITgcm have some diagnostics available to output it?
>>
>> The analytical formula based on bulk formulation can be written as:
>> Focn = Csens * Cp * Rho * (Ui-Uw)2 * (Ti -Tw)
>>
>> In pkg/seaice/seaice_growth.F I have found this variable for turbulent
>> ocean-ice heat flux converted to meters of potential ice melt:
>>
>> a_QbyOCN(i,j) = -tmpscal1 * (HeatCapacity_Cp*rhoConst/QI)
>> &                                  * (theta(I,J,kSurface,bi,bj)-TBC)
>>
>> After that I can divide it by convertQ2HI to obtain heat flux in W/m2:
>>
>> TurbIOCN(I,J) = a_QbyOCN(I,J) / convertQ2HI
>>
>> Is it correct? If yes, why was the dependence on the relative ocean-ice
>> velocity (or the Ustar) dropped? I see that Ustar was calculated for the
>> McPhee option, but this part of the code does not seem to be operational.
>>
>> Any help that you may provide regarding this issue would be welcome.
>>
>> Thank you,
>> Alexander Slavin,
>> McGill University, Canada
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