[MITgcm-support] Re: single-layer configuration problem update
Martin Losch
mlosch at awi-bremerhaven.de
Wed Aug 31 03:51:07 EDT 2005
David,
here's my personal experience:
I found reading input without the exf-pkg simple and convenient enough
for experiments with climatological forcing. You can use the exf-pkg
(+cal, of course) for the same results, but you have to use it if
1. you want to use different "forcingPeriods" for different fields
(e.g., read ustress data every day, heat flux data every 5 days, etc.)
2. you want to use the seaice-pkg, which is tightly integrated with the
exf-pkg (unfortunately); the thice-pkg (thermodynamic sea ice only, a
different sea ice model) works without exf (in fac I don't even know if
it works with exf, but I think so).
3. you want to use the bulk formulae of Large+Pond (1981/82, or so);
they are implemented in exf.
4. you want to use the ecco-package.
5. ???
Your questions:
- periodicExternalForcing has no effect when you use exf.
- externForcingPeriod: this flag shouldn't have (and does not have) any
effect, when you use exf. It is one of the advantages of exf, that you
can (and must) set the forcing period for each forcing field
individually
- externForcingCycle: has no effect when used with exf. Instead use
repeatPeriod in data.exf. Unfortunately this is a parameter for all
forcing fields, so make sure that you have enough recordings in each
data file, that is: repeatPeriod/ustressperiod records in you u-stress
data, and repeatPeriod/hfluxperiod in your heat flux data. I guess one
would expect that there is a repeatPeriod for each forcing field just
as there is a period for every forcing field, but currently there
isn't.
- tauThetaClimRelax and tauSaltClimRelax: these restoring/relaxatioin
constants are always set in "data", also when you use exf.
Martin
On Aug 30, 2005, at 7:45 PM, David Wang wrote:
> Hey all,
>
> I try to catch up this thread and throw out my question.
>
> If I use exf package to specify my wind stress forcing (monthly
> climatology) and restoring SST/SSS (also monthly climatology), do the
> following parameters in data namelist still count? I've not found the
> counterpart of externForcingCycle (supposed to be 1 year in my case)
> in data.exf and data.exf_clim namelists.
>
> periodicExternalForcing
> externForcingPeriod
> externForcingCycle
> tauThetaClimRelax
> tauSaltClimRelax
>
> Thanks,
> - D.W.
>
> Patrick Heimbach wrote:
>
>> Sergey,
>>
>> several things:
>> 1. I thought you were using the SINGLE_LAYER_MODE flag(?)
>> 2. The std. output has NAN's in cg2d after a few timesteps,
>> but you're saying the model doesn't explode.
>> Can you clarify?
>> 3. The alternative, simplere forcing would be via
>> S/R external_fields_load.F
>> and not using exf (i.e. remove 'exf' from packages.conf)
>> An example is in verification/global_ocean.90x40x15/code/
>>
>> -Patrick
>>
>>
>>
>> > -----Original Message-----
>> > From: mitgcm-support-bounces at mitgcm.org >
>> [mailto:mitgcm-support-bounces at mitgcm.org] On Behalf Of > Sergey
>> Vinogradov
>> > Sent: Tuesday, August 30, 2005 10:50 AM
>> > To: mitgcm-support at mitgcm.org
>> > Cc: Rui Ponte
>> > Subject: Re: [MITgcm-support] Re: single-layer > configuration
>> problem update
>> > > > Martin:
>> > I don't know of any other way than EXF to introduce the >
>> variable forcing > into the mitgcm. The resulting field is not
>> exploding > though, it stays > equal to i.c.
>> > Anyway, SINGLE_LAYER_MODE is probably what I was looking for in a
>> > context of my experiments.
>> > Thank you,
>> > Sergey
>> > > Martin Losch wrote:
>> > > > Sergey,
>> > > that's really puzzling. Have you tried the same thing without
>> the > > EXF-package? (I have had unexpected behavior with this >
>> package before).
>> > >
>> > > However, if --- as you suspect --- no forcing fields >
>> introduced by EXF > > is not "felt" by the model, then it wouldn't
>> explode, but > would just > > keep quiet without moving at all. So
>> I think, that on the > contrary, > > the model feels too much of
>> the forcing; or something completely > > different is going on.
>> > >
>> > > I can't remember your configuration, and obviously, I am > too
>> stupid to > > search the MITgcm-support email list effectively so I
>> > didn't find your > > previous emails, but were you using the
>> CPP-flag > SINGLE_LAYER_MODE > > (kicks out most of
>> thermodynamics)? However, even if you > were using > > it, I don't
>> see where it should interfere with the EXF package.
>> > >
>> > > Martin
>> > >
>> > > On Aug 30, 2005, at 3:49 PM, Sergey Vinogradov wrote:
>> > >
>> > >> Hi all,
>> > >>
>> > >> I just want to update you on my quest in solving the >
>> problem with > >> single-layer run under dynamic forcing (and maybe
>> get > some useful > >> feedback from you).
>> > >>
>> > >> The issue was erroneous computation of ocean dynamics >
>> (sea-level, > >> bottom pressure) in a single layer configuration
>> with a > use of EXF > >> package interface for the time-varying
>> atm. pressure loading.
>> > >>
>> > >> Appearently, it is not a problem of just pressure > loading.
>> It is far > >> more general problem, as I tried similar experiment
>> with > wind stress. > >> It looks like any forcing that is
>> introduced through EXF > in one-layer > >> run, is not "felt" by
>> the model.
>> > >>
>> > >> Below is the exerpt from the model output with one > layer
>> under wind > >> stress at the beginning of forward integration where
>> you > can see the > >> error accumulating in cg solver with each
>> step. Similar > run with 23 > >> layers computes reasonable fields.
>> > >>
>> > >> I'd appreciate any suggestions/comments/tips very much!
>> > >> Regards,
>> > >> Sergey
>> > >>
>> > >> (PID.TID 0000.0001) // > >>
>> =======================================================
>> > >> (PID.TID 0000.0001) // End MONITOR dynamic field statistics
>> > >> (PID.TID 0000.0001) // > >>
>> =======================================================
>> > >> (PID.TID 0000.0001) MDSREADFIELD: opening global file: > >>
>> /anvil/scratch/day07/svv/forcing/NCEP_R6_ustr_1999
>> > >> (PID.TID 0000.0001) MDSREADFIELD: opening global file: > >>
>> /anvil/scratch/day07/svv/forcing/NCEP_R6_ustr_1999
>> > >> cg2d: Sum(rhs),rhsMax = 5.83105612406154E-15 >
>> 2.52789606828280E+01
>> > >> cg2d: Sum(rhs),rhsMax = 4.66381008031730E-09 >
>> 2.03846096766287E+01
>> > >> cg2d: Sum(rhs),rhsMax = -7.72491057666330E-11 >
>> 1.63318316358843E+02
>> > >> cg2d: Sum(rhs),rhsMax = 7.82384650122037E-10 >
>> 3.94671184216402E+02
>> > >> cg2d: Sum(rhs),rhsMax = 1.84482164570718E-10 >
>> 1.39786242903642E+03
>> > >> cg2d: Sum(rhs),rhsMax = -3.86795120889058E-10 >
>> 5.51987500042437E+03
>> > >> cg2d: Sum(rhs),rhsMax = 5.60930842031203E-10 >
>> 2.96468380272229E+04
>> > >> cg2d: Sum(rhs),rhsMax = -4.60258786649532E-11 >
>> 1.03144921478204E+06
>> > >> cg2d: Sum(rhs),rhsMax = 1.93486835808804E-12 >
>> 3.16417950241384E+08
>> > >> cg2d: Sum(rhs),rhsMax = -2.47236726757771E-12 >
>> 2.35353664301718E+13
>> > >> cg2d: Sum(rhs),rhsMax = -3.50420466366502E-16 >
>> 2.44341352738558E+23
>> > >> cg2d: Sum(rhs),rhsMax = -2.42051059455915E-16 >
>> 1.68257839407874E+43
>> > >> cg2d: Sum(rhs),rhsMax = -2.02970152146811E-16 >
>> 1.42078931888867E+83
>> > >> cg2d: Sum(rhs),rhsMax = -4.29685153894816E-16 >
>> 9.27740314802081+162
>> > >> cg2d: Sum(rhs),rhsMax = NAN >
>> INF
>> > >> cg2d: Sum(rhs),rhsMax = NAN >
>> 0.00000000000000E+00
>> > >> cg2d: Sum(rhs),rhsMax = NAN >
>> 0.00000000000000E+00
>> > >> cg2d: Sum(rhs),rhsMax = NAN >
>> 0.00000000000000E+00
>> > >> (PID.TID 0000.0001) MDSREADFIELD: opening global file: > >>
>> /anvil/scratch/day07/svv/forcing/NCEP_R6_ustr_1999
>> > >> cg2d: Sum(rhs),rhsMax = NAN >
>> 0.00000000000000E+00
>> > >> cg2d: Sum(rhs),rhsMax = NAN >
>> 0.00000000000000E+00
>> > >>
>> > >
>> > >
>> > > _______________________________________________
>> > > MITgcm-support mailing list
>> > > MITgcm-support at mitgcm.org
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>> > > > _______________________________________________
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>> >
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>
>
> --
> Daiwei (David) Wang Graduate Student
> Lamont-Doherty Earth Observatory of Columbia University
> 103B Oceanography
> 61 Route 9W, Palisades, NY 10964-8000
> Voice: (845) 365-8694
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