[MITgcm-support] About pickup

[Christoph Voelker]

Dear Elisabei,

As you said, your problem most likely comes form changing the
externForcingPeriod, but leaving the Cycle at the same value.

If I understand your data-file for the spinup correctly, you have
monthly forcing over 12 years, i.e. 144 records stored in your forcing
fields. You just integrate 10 years, so the periodicity does not matter,
except for interpolating the forcing fields in the first half of the
first month of your model run.

Then you change your data file to switch from monthly to daily forcing.
You keep your external forcing CYCLE unchanged at 12 years, so the model
now assumes your input datasets have (12*360)=4320 records (once per day
over 12 years). The model then looks for records (10*360) and (10*360+1)
to calculate the forcing for the first day. But that only works if your
forcing fields really contain that many records. From your second
data-file I see that the forcing files for the second period are the
same as for the first period, at least they have the same name. Do you
use the same files? Then it is no wonder that the model complains that
the files do not contain as many records as it expects. The files should
be either 30 times larger (in bytes) that during the first period, or
you have to adapt your external forcing cycle.

I hope this helps,
Cheers, Christoph

Am 08/09/16 um 15:21 schrieb elisabei:
> Dear:
>
>   I have a problem about the use of pickup file.
>
> First step:I run the mitgcm using the monthly climatology initial fields and external forcing fields  about 10 years to get the stable model.
>
> the data file show follow
>
>  startTime=0,
>  endTime=311040000,
>  deltaTmom=60.0,
>  deltaTtracer=240.0,
>  deltaTClock =1200.0,
>  pChkptFreq=31104000.,
>  dumpFreq=259200.0,
>  tauThetaClimRelax=864000.0,
>  tauSaltClimRelax=864000.0,
>  periodicExternalForcing=.TRUE.,
>  externForcingPeriod=259200.,
>  externForcingCycle=373248000.,
>  zonalWindFile='dasilva_taux_12y.bin',
>  meridWindFile='dasilva_tauy_12y.bin',
>  thetaClimFile='lev_monthly_12y.bin',
>  saltClimFile='lev_monthly_12y.bin',
>
> Second step:I run the model using the really daily external forcing fields about 2 years to simulate the real ocean dynamical field. 
>
> the data file show follow
>
>  startTime=311040000,
>  endTime=373248000,
>  deltaTmom=60.0,
>  deltaTtracer=240.0,
>  deltaTClock =1200.0,
>  pChkptFreq=259200.,
>  dumpFreq=86400.0,
>  tauThetaClimRelax=864000.0,
>  tauSaltClimRelax=864000.0,
>  periodicExternalForcing=.TRUE.,
>  externForcingPeriod=86400.,
>  externForcingCycle=373248000.,
>  zonalWindFile='dasilva_taux_12y.bin',
>  meridWindFile='dasilva_tauy_12y.bin',
>  thetaClimFile='lev_monthly_12y.bin',
>  saltClimFile='lev_monthly_12y.bin',
>
> When I run the model at second step,the program prompt error "PGFIO-F-253/unformatted read/unit=9/attempt to read non-existent record (direct access).
>  File name = OBE_U_1982_2014.bin    unformatted, direct access   record = 7084480 In source file mdsio_slice.f, at line number 3037".
>
> I think the reason caused it is the change of the "externForcingPeriod" .
>
> So would you like to tell me how can I do to solve the problem?
>
>
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-- 
Christoph Voelker
Alfred Wegener Institute for Polar and Marine Research
Am Handelshafen 12
27570 Bremerhaven, Germany
e: Christoph.Voelker at awi.de
t: +49 471 4831 1848

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