[MITgcm-support] balancing the heat equation
Nicolas Wienders
wienders at ocean.fsu.edu
Thu Sep 6 14:06:22 EDT 2007
MITgcmers,
First my apologies for posting yesterday on the list a message
that obviously should not have.
> Hi Allison,
> without checking details in the code I would suggest that you use
> the diagnostics package for diagnosing the different contributions.
> As far as I can see, the diagnostics are all available:
> dT/dt:
> diagName = 'TOTTTEND'
> diagTitle = 'Tendency of Potential Temperature'
> uTx/vTy/wTz: 'ADVx/y/r_TH '
> KTxx/yy/zz: 'DFx/y/rE_TH ' (and 'DFrI_TH ' for the implicit part
> which is relevant for KPP)
> Then there is the non-local term in KPP, which can be diagnosed
> with 'KPPghat '; however that is not the contribution to diffusive
> flux, and you'll have to alter the code a little to get that
> contribution with the diagnostics package. Here's a hack that
> abuses DFrE_TH for this purpose: In gad_calc_rhs.F find the calls
> to KPP_TRANSPORT_T etc. They are within a #ifdef ALLOW_KPP/#endif
> block. just before this there is a diagnostics call (#ifdef
> ALLOW_DIAGNOSTICS/#endif). Just exchange the order of these two
> blocks and DFrE_TH will give you the flux-contribution of the non-
> local term (but the explicit diffusive flux will be overwritten and
> not diagnosed, which is only OK, if you are using KPP without
> GMREDI!).
> A better solution is to add a new diagnostic and insert it after
> the calls to KPP_TRANSPORT_T etc).
Second, and following Allison's question, how should one write the
heat equation
(using KPP and not gmredi) in order to reach a machine precision
balance. We have
been trying for a while without any success. We are mostly concerned
by the non-local
term but might already be wrong upstream. So far we only have the
volume balance
correct.
Thanks a lot.
--
Nicolas Wienders (850) 644-1987 (office)
Florida State University 294-3542 (cell)
Oceanography - OSB415 644-2581 (fax)
P.O. Box 3064320 117 N. Woodward Avenue
Tallahassee, FL 32306-4320 wienders at ocean.fsu.edu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20070906/a802c120/attachment.htm>
More information about the MITgcm-support
mailing list