[MITgcm-support] Heat budget in MITGCM
Ryan Abernathey
ryan.abernathey at gmail.com
Wed Nov 26 14:19:14 EST 2014
Hi Abhisek,
Why don't you write a short technical report on how you managed to close
your budget and email it back to the list? The next time someone asks this
question, we will be able to point them to your report.
-Ryan
On Wed, Nov 26, 2014 at 12:14 PM, Abhisek Chakraborty <abhisek.sac at gmail.com
> wrote:
> Dear Jean-Michel,
>
> Many thanks for all your suggestions and guidances. Finally I am able to
> close the heat budget at surface too.
>
> Thank you once again,
>
> regards,
> Abhisek
> On 25 Nov 2014 23:26, "Jean-Michel Campin" <jmc at ocean.mit.edu> wrote:
>
>> Hi Abhisek,
>>
>> Unless I forgot something, I would recommand to try to close the surface
>> level heat budget using the expression you just wrote below (seems good
>> to me when using linear free-surface).
>>
>> Cheers,
>> Jean-Michel
>>
>> On Tue, Nov 25, 2014 at 10:46:31PM +0530, Abhisek Chakraborty wrote:
>> > Dear Jean-Michel,
>> >
>> > The figures (posted in my earlier mail) represents the various terms
>> > required for closing the heat budget at surface as well as at a depth of
>> > 20m (sub-surface) at a particular location (90E12N). All the terms are
>> > daily time series at that location (no horizontal mean).
>> >
>> > For the surface level, I am using the TFLUX diagnostics. From your mail
>> > what I understand is that
>> >
>> > tend_heat_surf = tend_advection +
>> > tend_diffusion +
>> > tend_kpp +
>> >
>> (TFLUX-oceQsw)/(rhoConst*Cp*DRF(1)*hFacC(i,j,1))
>> > +
>> >
>> > tend_Qsw -
>> > (WTHMASS(i,j,1) -
>> > TsurfCor)/(DRF(1)*hFacC(i,j,1))
>> > where
>> > tend_Qsw =
>> oceQsw/(rhoConst*Cp)/(DRF(1)*hFacC(i,j,1))*(swfrac(1)-swfrac(2))
>> > and
>> > TsurfCor = SUM( WTHMASS(i,j,1)*RAC(i,j) ) / globalArea
>> >
>> > and "swfrac" is already defined in our earlier communications.
>> >
>> > Am I correct?
>> >
>> > Thanking in advance,
>> > Abhisek
>> >
>> >
>> >
>> >
>> >
>> *--------------------------------------------------------------------------------ABHISEK
>> > CHAKRABORTY*
>> >
>> > *Scientist - "SD"Oceanic Sciences Division (*
>> > *AOSG/EPSA)*
>> >
>> > *Space Applications Centre*
>> >
>> > *Indian Space Research Organization*
>> >
>> > *Ahmedabad - 380 015*
>> >
>> > *Gujarat, INDIA*
>> > *Contact: +91-79-2691-6054 (O), +91-79-2686-1929(R)*
>> >
>> > On Tue, Nov 25, 2014 at 2:21 AM, Jean-Michel Campin <jmc at ocean.mit.edu>
>> > wrote:
>> >
>> > > Hi Abhisek,
>> > >
>> > > > Following your suggestions, I think I am now able to close the heat
>> > > budget
>> > > > for the subsurface levels.
>> > > This is good news.
>> > >
>> > > > I have attached two figures (one for subsurface at 20 m depth and
>> another
>> > > > for surface).
>> > > Could you clarify what is represented on these 2 figs: it is for a
>> > > single grid point (but where ?) or the horizontal mean ?
>> > >
>> > > Regarding the surface forcing, which diagnostics are you using:
>> > > surForcT ? TFLUX ? or oceQnet and TRELAX ?
>> > >
>> > > If you are using TFLUX (which contains the vertically integrated SW
>> > > heating)
>> > > for the surface budget, you may want to remove oceQsw and then
>> > > add back tend_Qsw(k=1) (as you wrote below).
>> > >
>> > > Cheers,
>> > > Jean-Michel
>> > >
>> > > On Fri, Nov 21, 2014 at 07:13:31PM +0530, Abhisek Chakraborty wrote:
>> > > > Dear Jean-Michel,
>> > > >
>> > > > To close the surface heat budget, I followed your suggestion:
>> > > >
>> > > >
>> > >
>> > > TsurfCor = SUM( WTHMASS(i,j,1)*RAC(i,j) ) / globalArea
>> > > > and finally:
>> > > > tend_T = (...) - ( WTHMASS(i,j,1) - TsurfCor
>> )/(drF(1)*hFacC(i,j,1))
>> > > >
>> > > > Also, the shortwave tendency terms is computed as:
>> > > >
>> > > > tend_Qsw = oceQsw/(rhoConst*Cp)/(drF(k)*hFacC(I,j,k))
>> > > > * ( swfrac(k) - swfrac(k+1) )
>> > > > where for surface, k=1
>> > > >
>> > > > But in this way, the surface tendency term is becoming one order
>> higher
>> > > in
>> > > > magnitude than other terms (advection, diffusion, surface
>> correction.
>> > > Pls.
>> > > > see the figure in my earlier mail).
>> > > >
>> > > > So, please guide me how to close the budget at surface.
>> > > >
>> > > > regards,
>> > > > Abhisek
>> > > >
>> > > >
>> > > >
>> > > >
>> > > >
>> > > >
>> > >
>> *--------------------------------------------------------------------------------ABHISEK
>> > > > CHAKRABORTY*
>> > > >
>> > > > *Scientist - "SD"Oceanic Sciences Division (*
>> > > > *AOSG/EPSA)*
>> > > >
>> > > > *Space Applications Centre*
>> > > >
>> > > > *Indian Space Research Organization*
>> > > >
>> > > > *Ahmedabad - 380 015*
>> > > >
>> > > > *Gujarat, INDIA*
>> > > > *Contact: +91-79-2691-6054 (O), +91-79-2686-1929(R)*
>> > > >
>> > > > On Thu, Nov 20, 2014 at 6:59 PM, Abhisek Chakraborty <
>> > > abhisek.sac at gmail.com>
>> > > > wrote:
>> > > >
>> > > > > Hi Jean-Michel,
>> > > > >
>> > > > > Sorry for delayed reply.
>> > > > >
>> > > > > Following your suggestions, I think I am now able to close the
>> heat
>> > > budget
>> > > > > for the subsurface levels.
>> > > > >
>> > > > > However, in spite of my different attempts I am not able to close
>> the
>> > > > > budget at surface where I am finding the surface correction term
>> (as
>> > > > > specified in your mail) along with other advection-diffusion
>> terms are
>> > > too
>> > > > > small to balance the shortwave heating term.
>> > > > >
>> > > > > I have attached two figures (one for subsurface at 20 m depth and
>> > > another
>> > > > > for surface).
>> > > > >
>> > > > > Pls. let me know if I am missing something.
>> > > > >
>> > > > > Thanking in advance,
>> > > > > Abhisek
>> > > > >
>> > > > >
>> > > > >
>> > > > >
>> > >
>> *--------------------------------------------------------------------------------ABHISEK
>> > > > > CHAKRABORTY*
>> > > > >
>> > > > > *Scientist - "SD"Oceanic Sciences Division (*
>> > > > > *AOSG/EPSA)*
>> > > > >
>> > > > > *Space Applications Centre*
>> > > > >
>> > > > > *Indian Space Research Organization*
>> > > > >
>> > > > > *Ahmedabad - 380 015*
>> > > > >
>> > > > > *Gujarat, INDIA*
>> > > > > *Contact: +91-79-2691-6054 (O), +91-79-2686-1929(R)*
>> > > > >
>> > > > > On Wed, Nov 19, 2014 at 1:19 AM, Jean-Michel Campin <
>> jmc at ocean.mit.edu
>> > > >
>> > > > > wrote:
>> > > > >
>> > > > >> Hi Abhisek,
>> > > > >>
>> > > > >> This budget looks better. Just few remarks (see below).
>> > > > >>
>> > > > >> On Tue, Nov 18, 2014 at 11:20:46PM +0530, Abhisek Chakraborty
>> wrote:
>> > > > >> > Dear Jean-Michel,
>> > > > >> >
>> > > > >> > Thanks for your prompt suggestion.
>> > > > >> >
>> > > > >> >
>> > > > >> > (1) the advection term for k>1 will be
>> > > > >> >
>> > > > >> > - [ (ADVx_TH(i+1,j,k) – ADVx_TH(I,j,k))/CV +
>> > > > >> >
>> > > > >> > (ADVy_TH(I,j+1,k) – ADVy_TH(I,j,k))/CV +
>> > > > >> >
>> > > > >> > (ADVr_TH(I,j,k+1) – ADVr_TH(I,j,k))/CV ]
>> > > > >>
>> > > > >> The vertical advective & diffusive transport/flux are (I think)
>> > > > >> positive in the direction of the vertical coordinate, i.e.,
>> > > > >> when using z-coords, positive upward. So you will have to
>> reverse
>> > > > >> (or add a minus sign) in front of:
>> > > > >> (ADVr_TH(I,j,k+1) – ADVr_TH(I,j,k))/CV
>> > > > >>
>> > > > >> >
>> > > > >> > Where CV=Ac * del RF * Hc = RAC(I,j) * (RF(K+1)-RF(K)) *
>> > > hFacC(I,j,k)
>> > > > >> >
>> > > > >> > (
>> > > > >>
>> > >
>> http://mitgcm.org/public/r2_manual/latest/online_documents/node73.html)
>> > > > >> >
>> > > > >> >
>> > > > >> >
>> > > > >> > And similarly the diffusion and KPP terms. Correct?
>> > > > >> >
>> > > > >> >
>> > > > >> > (2) The source term (shortwave) for k>1 will be the following
>> > > > >> >
>> > > > >> > depth=RF(k)
>> > > > >> >
>> > > > >> > swfrac=0.62*exp(depth/0.6) + (1.0-0.62) * exp(depth/20)
>> > > > >> >
>> > > > >> > if(depth < -200.0) swfrac=0.0
>> > > > >> >
>> > > > >> > source term = (oceQsw/(rhoConst*Cp)) * swfrac *
>> hFacC(I,j,k)
>> > > > >> >
>> > > > >> > Is this correct for k>1 ?
>> > > > >>
>> > > > >> This does not look right:
>> > > > >> from depth=RF(k) , we compute swfrac(k) as above
>> > > > >> from depth=RF(k+1), we compute swfrac(k+1) as above except
>> that
>> > > > >> at the bottom (deepest level of this column) swfrac(k+1)=0.
>> > > > >> and the tendency contribution from shortwave heating should be
>> > > something
>> > > > >> like:
>> > > > >> tend_Qsw = oceQsw/(rhoConst*Cp)/(drF(k)*hFacC(I,j,k))
>> > > > >> * ( swfrac(k) - swfrac(k+1) )
>> > > > >> >
>> > > > >> > (3) I am using the tendency as TOTTTEND/86400. Is it correct?
>> > > > >>
>> > > > >> yes, providing you are using linear free-surface.
>> > > > >>
>> > > > >> >
>> > > > >> > (4) I am using linFSConserveTr=TRUE. Yet I have to use
>> > > > >> > WTHMASS(i,j,1)*RAC(i,j) to correct the heat budget at the
>> surface?
>> > > > >>
>> > > > >> Yes, but since you are using linFSConserveTr=TRUE., the global
>> mean
>> > > > >> value of WTHMASS has to be removed in the budget (like it is
>> in the
>> > > > >> model):
>> > > > >> TsurfCor = SUM( WTHMASS(i,j,1)*RAC(i,j) ) / globalArea
>> > > > >> and finally:
>> > > > >> tend_T = (...) - ( WTHMASS(i,j,1) - TsurfCor
>> )/(drF(1)*hFacC(i,j,1))
>> > > > >>
>> > > > >> Cheers,
>> > > > >> Jean-Michel
>> > > > >>
>> > > > >> >
>> > > > >> > Thanking in advance,
>> > > > >> >
>> > > > >> > Abhisek
>> > > > >> >
>> > > > >> >
>> > > > >> >
>> > > > >> >
>> > > > >>
>> > >
>> *--------------------------------------------------------------------------------ABHISEK
>> > > > >> > CHAKRABORTY*
>> > > > >> >
>> > > > >> > *Scientist - "SD"Oceanic Sciences Division (*
>> > > > >> > *AOSG/EPSA)*
>> > > > >> >
>> > > > >> > *Space Applications Centre*
>> > > > >> >
>> > > > >> > *Indian Space Research Organization*
>> > > > >> >
>> > > > >> > *Ahmedabad - 380 015*
>> > > > >> >
>> > > > >> > *Gujarat, INDIA*
>> > > > >> > *Contact: +91-79-2691-6054 (O), +91-79-2686-1929(R)*
>> > > > >> >
>> > > > >> > On Tue, Nov 18, 2014 at 10:42 PM, Jean-Michel Campin <
>> > > jmc at ocean.mit.edu
>> > > > >> >
>> > > > >> > wrote:
>> > > > >> >
>> > > > >> > > Hi Abhisek,
>> > > > >> > >
>> > > > >> > > I would recommand to concentrate first on any level except
>> the
>> > > surface
>> > > > >> > > (k=1),
>> > > > >> > > and try to close the budget ; then, once you get a clean
>> closed
>> > > budget
>> > > > >> > > for levels at depth, you can revisit the surface level
>> problem.
>> > > > >> > >
>> > > > >> > > at depth (k>1):
>> > > > >> > > the way you estimate the tendency is not what is done in the
>> > > model,
>> > > > >> > > see e.g.:
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/public/r2_manual/latest/online_documents/node73.html
>> > > > >> > >
>> > > > >> > > The diagnostics for the KPP non-local term is like a
>> vertical flux
>> > > > >> > > (added to fVerT), so it can be treated (for budget purpose)
>> the
>> > > same
>> > > > >> way
>> > > > >> > > as DIFrI_TH.
>> > > > >> > >
>> > > > >> > > at the surface, you can search the mitgcm-support archive
>> and find
>> > > > >> some
>> > > > >> > > information there, e.g.:
>> > > > >> > >
>> http://mitgcm.org/pipermail/mitgcm-support/2014-April/009093.html
>> > > > >> > > but it's likely that you would need additional diagnostics
>> > > output,i
>> > > > >> > > e.g. WTHMASS & WSLTMASS at k=1.
>> > > > >> > >
>> > > > >> > > Cheers,
>> > > > >> > > Jean-Michel
>> > > > >> > >
>> > > > >> > > On Tue, Nov 18, 2014 at 09:49:34PM +0530, Abhisek Chakraborty
>> > > wrote:
>> > > > >> > > > Many thanks Ryan, Dimitris, John and Gael for your
>> suggestions.
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > I am not much familiar with MATLAB, so for me it was too
>> much
>> > > > >> difficult
>> > > > >> > > to
>> > > > >> > > > understand the code shared by Gael, though I tried to look
>> into
>> > > it.
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > As a matter of fact is that I am using is the ECCO1
>> version (1
>> > > deg
>> > > > >> > > global,
>> > > > >> > > > 50 levels, excluding poles; i=1:360; j=1:160; k=1:50) of
>> MITGCM
>> > > with
>> > > > >> > > linear
>> > > > >> > > > free surface and linFSConserveTR=True. The diagnostic
>> > > parameters are
>> > > > >> > > > written in every day with diagnostic timephase=0. Model
>> > > > >> parameterizations
>> > > > >> > > > are KPP and GM-Redi.
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > I’d like to analyze the heat budget at a particular
>> location,
>> > > say,
>> > > > >> > > (i,j,k).
>> > > > >> > > > So, from the suggestions by Ryan, Dimitris and looking
>> into the
>> > > > >> Gael’s
>> > > > >> > > > code, I am trying the following:
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > !!Cell volumes (center difference)
>> > > > >> > > >
>> > > > >> > > > Cvx = (RAC(i+1,j) - RAC(i-1,j)) * RF(k) * hFacC(i,j,k)
>> > > > >> > > >
>> > > > >> > > > Cvy = (RAC(i,j+1) - RAC(i,j-1)) * RF(k) * hFacC(i,j,k)
>> > > > >> > > >
>> > > > >> > > > Cvz = RAC(i,j) * (RF(k+1) – RF(k)) * hFacC(i,j,k)
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > !!Divergence of advection & diffusion by center difference
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > if (k>1) then
>> > > > >> > > >
>> > > > >> > > > adc_dif_vert_k = (ADVr_TH(i,j,k+1) –
>> > > ADVr_TH(I,j,k-1))/cvz
>> > > > >> +
>> > > > >> > > >
>> > > > >> > > > (DIFrE_TH(I,j,k+1) –
>> > > > >> > > DIFrE_TH(I,j,k-1))/cvz +
>> > > > >> > > >
>> > > > >> > > > (DIFrI_TH(I,j,k+1) –
>> > > > >> DIFrI_TH(I,j,k-1))/cvz
>> > > > >> > > >
>> > > > >> > > > else
>> > > > >> > > >
>> > > > >> > > > adc_dif_vert_k = 0.0
>> > > > >> > > >
>> > > > >> > > > endif
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > adc_dif_hori_k = (ADVx_TH(i+1,j,k) – ADVx_TH(i-1,j,k))/cvx
>> +
>> > > > >> > > >
>> > > > >> > > > (ADVy_TH(i,j+1,k) –
>> > > ADVy_TH(i,j-1,k))/cvy +
>> > > > >> > > >
>> > > > >> > > > (DIFxE_TH(i+1,j,k) –
>> > > > >> DIFxE_TH(i-1,j,k))/cvx +
>> > > > >> > > >
>> > > > >> > > > (DIFyE_TH(i,j+1,k) –
>> > > DIFyE_TH(i,j-1,k))/cvy
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > !!To account for the shortwave heating
>> > > > >> > > >
>> > > > >> > > > depth=RF(k)
>> > > > >> > > >
>> > > > >> > > > swfrac=0.62*exp(depth/0.6) + (1.0-0.62) * exp(depth/20)
>> > > > >> > > >
>> > > > >> > > > if(depth < -200.0) then
>> > > > >> > > >
>> > > > >> > > > swfrac=0.0
>> > > > >> > > >
>> > > > >> > > > endif
>> > > > >> > > >
>> > > > >> > > > if (k=1)then
>> > > > >> > > >
>> > > > >> > > > swfrac=1.0
>> > > > >> > > >
>> > > > >> > > > endif
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > !!Finally balance
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > TOTTTEND/86400.0 = - adc_dif_vert_k - adc_dif_hori_k +
>> > > > >> > > > (oceQsw/(rhoConst*Cp)) * swfrac * hFacC(I,j,k) +
>> KPPg_TH(i,j,k)
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > Please let me know whether I am doing properly or not.
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > > Thanking in advance,
>> > > > >> > > >
>> > > > >> > > > Abhisek
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > > >
>> > > > >> > >
>> > > > >>
>> > >
>> *--------------------------------------------------------------------------------ABHISEK
>> > > > >> > > > CHAKRABORTY*
>> > > > >> > > >
>> > > > >> > > > *Scientist - "SD"Oceanic Sciences Division (*
>> > > > >> > > > *AOSG/EPSA)*
>> > > > >> > > >
>> > > > >> > > > *Space Applications Centre*
>> > > > >> > > >
>> > > > >> > > > *Indian Space Research Organization*
>> > > > >> > > >
>> > > > >> > > > *Ahmedabad - 380 015*
>> > > > >> > > >
>> > > > >> > > > *Gujarat, INDIA*
>> > > > >> > > > *Contact: +91-79-2691-6054 (O), +91-79-2686-1929(R)*
>> > > > >> > > >
>> > > > >> > > > On Tue, Nov 18, 2014 at 5:06 AM, gael forget <
>> gforget at mit.edu>
>> > > > >> wrote:
>> > > > >> > > >
>> > > > >> > > > > Hi Abhisek, et al,
>> > > > >> > > > >
>> > > > >> > > > > the following matlab code may provide some guidance :
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/gael/matlab_class/gcmfaces_diags/diags_set_D.m
>> > > > >> > > > >
>> > > > >> > > > > It does not cover every possible combination of model
>> options
>> > > > >> > > > > (e.g., no kpp or thsice) of course, but treats a few. In
>> that
>> > > > >> code,
>> > > > >> > > > > it is assumed that
>> > > > >> > > > > 1) the setting for the diagnostics package was according
>> to
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/gael/verification/global_oce_llc90/input/data.diagnostics
>> > > > >> > > > > which includes vertical integration. The relevant
>> > > diagnostics
>> > > > >> > > > > for budget are those with filename like
>> > > > >> 'diags/budg2d_snap_set1',
>> > > > >> > > > > 2) tendencies have been pre-computed by differencing
>> between
>> > > > >> > > > > consecutive (monthly) snap shots — so that ETAN
>> > > > >> > > > > really means dETAN/dt in this context, and similarly
>> for
>> > > > >> > > > > THETA, SALT, etc. The other variable names used in
>> > > > >> > > > > diags_set_D.m
>> > > > >> > > > > <
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/gael/matlab_class/gcmfaces_diags/diags_set_D.m
>> > > > >> >
>> > > > >> > > match
>> > > > >> > > > > those used in pkg/diagnostics
>> > > > >> > > > >
>> > > > >> > > > > I should also mention that diags_set_D.m
>> > > > >> > > > > <
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/gael/matlab_class/gcmfaces_diags/diags_set_D.m
>> > > > >> >
>> > > > >> > > is
>> > > > >> > > > > part of a
>> > > > >> > > > > broader framework (gcmfaces) which is documented in
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/viewvc/*checkout*/MITgcm/MITgcm_contrib/gael/matlab_class/gcmfaces.pd
>> > > > >> > > > > <
>> > > > >> > >
>> > > > >>
>> > >
>> http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/gael/matlab_class/gcmfaces.pd
>> > > > >> > > >
>> > > > >> > > > > f
>> > > > >> > > > > … although I am afraid this documentation is also
>> > > > >> > > > > lacking wrt the budget diagnostic codes.
>> > > > >> > > > >
>> > > > >> > > > > Cheers,
>> > > > >> > > > > Gael
>> > > > >> > > > >
>> > > > >> > > > > On Nov 17, 2014, at 5:53 PM, Dimitris Menemenlis <
>> > > > >> > > dmenemenlis at gmail.com>
>> > > > >> > > > > wrote:
>> > > > >> > > > >
>> > > > >> > > > > … and you probably already know this, but not clear from
>> your
>> > > > >> email:
>> > > > >> > > > > shortwave is not dumped in surface level only, but
>> rather is
>> > > > >> > > distributed
>> > > > >> > > > > with exponentially
>> > > > >> > > > > decaying profile in top 200-m, with subtle modifications
>> if
>> > > this
>> > > > >> > > heating
>> > > > >> > > > > is occurring within
>> > > > >> > > > > the KPP mixing layer depth.
>> > > > >> > > > >
>> > > > >> > > > > On Nov 17, 2014, at 2:44 PM, Ryan Abernathey <
>> > > > >> > > ryan.abernathey at gmail.com>
>> > > > >> > > > > wrote:
>> > > > >> > > > >
>> > > > >> > > > > Abhisek,
>> > > > >> > > > >
>> > > > >> > > > > This is a very common question that unfortunately is not
>> > > > >> documented
>> > > > >> > > very
>> > > > >> > > > > well. A couple of suggestions...
>> > > > >> > > > >
>> > > > >> > > > > For the transport terms, (ADV* and DF*), keep in mind
>> that
>> > > these
>> > > > >> are
>> > > > >> > > FLUX
>> > > > >> > > > > terms, defined on the cell boundaries. In order to
>> calculate a
>> > > > >> heat
>> > > > >> > > budget,
>> > > > >> > > > > you need to calculate the DIVERGENCE of those fluxes.
>> > > > >> > > > >
>> > > > >>
>> > >
>> http://mitgcm.org/public/r2_manual/latest/online_documents/node71.html
>> > > > >> > > > > Maybe this is obvious, but your email did not make it
>> clear
>> > > > >> whether you
>> > > > >> > > > > were doing this or not.
>> > > > >> > > > >
>> > > > >> > > > > Likewise, TFLUX is the downward flux at the surface, in
>> > > W/m^2. In
>> > > > >> > > order to
>> > > > >> > > > > convert to temperature units, you need to divide by
>> > > > >> > > > > HeatCapacity_Cp*rUnit2mass. For z coordinates,
>> rUnit2mass is
>> > > equal
>> > > > >> > > > > to rhoConst.
>> > > > >> > > > >
>> > > > >> > > > > There are some subtleties regarding tracer budgets under
>> > > > >> different free
>> > > > >> > > > > surface treatments. Maybe someone else on the list
>> understands
>> > > > >> this
>> > > > >> > > issue
>> > > > >> > > > > better and is willing to explain. Anyway, those should be
>> > > > >> second-order
>> > > > >> > > > > effects.
>> > > > >> > > > >
>> > > > >> > > > > Good luck with your analysis.
>> > > > >> > > > >
>> > > > >> > > > > -Ryan
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > > > > On Sat, Nov 15, 2014 at 2:29 AM, Abhisek Chakraborty <
>> > > > >> > > > > abhisek.sac at gmail.com> wrote:
>> > > > >> > > > >
>> > > > >> > > > >> Dear Users,
>> > > > >> > > > >>
>> > > > >> > > > >> I am trying to analyze heat budget in MITGCM. From the
>> > > diagnostic
>> > > > >> > > > >> outputs I have the following terms
>> > > > >> > > > >>
>> > > > >> > > > >> TOTTTEND , ADVr_TH, ADVx_TH, ADVy_TH, DFrE_TH, DFxE_TH,
>> > > DFyE_TH,
>> > > > >> > > > >> DFrI_TH, KPPg_TH, TFLUX (i.e. all terms corresponding to
>> > > > >> tendency,
>> > > > >> > > > >> advection, diffusion, KPP and total heat flux).
>> > > > >> > > > >>
>> > > > >> > > > >> Apart from these, I have other usual outputs like
>> THETA, SALT
>> > > > >> etc.
>> > > > >> > > > >>
>> > > > >> > > > >> The tendency term is in degC/day, the other terms are in
>> > > > >> degC*m^3/s
>> > > > >> > > > >> and TFLUX is in W/m^2. Thus I have converted the
>> tendency
>> > > term
>> > > > >> into
>> > > > >> > > > >> degC/s by dividing by 86400.0 and the
>> advection-diffusion
>> > > terms
>> > > > >> are
>> > > > >> > > > >> divided by cell volume (=RAC*RF*HFACC).
>> > > > >> > > > >>
>> > > > >> > > > >> I am using "linFSconserveTr=True".
>> > > > >> > > > >>
>> > > > >> > > > >> For the surface layer I have to consider TFLUX
>> (watt/m^2),
>> > > but
>> > > > >> how to
>> > > > >> > > > >> convert it into degC/s unit?
>> > > > >> > > > >>
>> > > > >> > > > >> For subsurface levels, I am trying to equate tendency
>> term
>> > > with
>> > > > >> > > > >> (advection + diffusion + KPP term). But there is a
>> mismatch.
>> > > > >> > > > >>
>> > > > >> > > > >> Can somebody please guide me how to achieve the exact
>> heat
>> > > > >> budget for
>> > > > >> > > > >> both surface and subsurface levels ?
>> > > > >> > > > >>
>> > > > >> > > > >> Thanking in advance,
>> > > > >> > > > >> Abhisek
>> > > > >> > > > >>
>> > > > >> > > > >> --
>> > > > >> > > > >>
>> > > > >> > > > >>
>> > > > >> > > > >> *ABHISEK CHAKRABORTY*
>> > > > >> > > > >>
>> > > > >> > > > >> *Scientist - "SD"Oceanic Sciences Division (*AOSG/EPSA)*
>> > > > >> > > > >>
>> > > > >> > > > >> *Space Applications Centre*
>> > > > >> > > > >>
>> > > > >> > > > >> *Indian Space Research Organization*
>> > > > >> > > > >>
>> > > > >> > > > >> *Ahmedabad - 380 015*
>> > > > >> > > > >>
>> > > > >> > > > >> *Gujarat, INDIA*
>> > > > >> > > > >> *Contact: +91-79-2691-6054 (O), +91-79-2686-1929(R)*
>> > > > >> > > > >>
>> > > > >> > > > >
>> > > > >> > > > > _______________________________________________
>> > > > >> > > > > MITgcm-support mailing list
>> > > > >> > > > > MITgcm-support at mitgcm.org
>> > > > >> > > > > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > > > > _______________________________________________
>> > > > >> > > > > MITgcm-support mailing list
>> > > > >> > > > > MITgcm-support at mitgcm.org
>> > > > >> > > > > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > > > >> > > > >
>> > > > >> > > > >
>> > > > >> > >
>> > > > >> > > > _______________________________________________
>> > > > >> > > > MITgcm-support mailing list
>> > > > >> > > > MITgcm-support at mitgcm.org
>> > > > >> > > > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > > > >> > >
>> > > > >> > >
>> > > > >> > > _______________________________________________
>> > > > >> > > MITgcm-support mailing list
>> > > > >> > > MITgcm-support at mitgcm.org
>> > > > >> > > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > > > >> > >
>> > > > >>
>> > > > >> > _______________________________________________
>> > > > >> > MITgcm-support mailing list
>> > > > >> > MITgcm-support at mitgcm.org
>> > > > >> > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > > > >>
>> > > > >>
>> > > > >> _______________________________________________
>> > > > >> MITgcm-support mailing list
>> > > > >> MITgcm-support at mitgcm.org
>> > > > >> http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > > > >>
>> > > > >
>> > > > >
>> > >
>> > > > _______________________________________________
>> > > > MITgcm-support mailing list
>> > > > MITgcm-support at mitgcm.org
>> > > > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > >
>> > >
>> > > _______________________________________________
>> > > MITgcm-support mailing list
>> > > MITgcm-support at mitgcm.org
>> > > http://mitgcm.org/mailman/listinfo/mitgcm-support
>> > >
>>
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>> > http://mitgcm.org/mailman/listinfo/mitgcm-support
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>>
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>
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