[MITgcm-support] nTimeStep

[Jody Klymak]

What did STDOUT say?  What is your value of hFac min?

Cheers,  Jody


On 9 Jun 2017, at 8:02, smaeilpour wrote:

> Thank you Jody,
> I restarted with a deltaT=5, that is small as following:
>
> startTime=0,
> endTime=86400,
> deltaT=5,
>
> but Model after a while (about 1500 of nTimeStep) becomes unstable, 
> what solution else do you offer except that? and what CFL criteria 
> else should i consider for it?
>
> Thank you again,
> Saeid
>
>
>
> --------------------------------------------
> On Wed, 6/7/17, Jody Klymak <jklymak at uvic.ca> wrote:
>
>  Subject: Re: [MITgcm-support] nTimeStep
>  To: mitgcm-support at mitgcm.org
>  Date: Wednesday, June 7, 2017, 12:26 PM
>
>
>
>  9 times out of 10 you will get this if deltaT is too
>  large.  Look for advcfl_*_max in
>  STDOUT.0000.  They should be less than one, and
>  preferably less than 0.5. A couple of things to be aware of
>
>
>  setting hFacMin to be too
>  small value can mean your vertical cell is very small, and
>  the CFL
>  condition becomes impossible to meet.  hFacMin
>  is the fraction of dR that a cell is allowed to
>  be near the bottom, so dR=10 m and
>  hFacMin=0.1 means the cell can be as thin as 1
>  m. If your deltaT=50 then W
>  can’t exceed 2 cm/s in that cell.  If the topography is
>  steep that is not a gigantic value for W near
>  topography.you may have strong start-up
>  transients in your solution that make the model behave more
>  violently at the start than after it has been allowed to
>  evolve.  So check STDOUT.0000 and if the CFL
>  criteria starts to drop again, you may be able to restart
>  with a smaller deltaT.
>
>
>  Good luck,  Jody
>
>  On 7 Jun 2017, at 8:35,
>  smaeilpour wrote:
>
>
>  Hi everyone,
>
>  I am trying to run Internal wave, my bathymetry file is
>  2160*876 and precision 30s. I'd like to run it in 38
>  layer and by 3500m depth. The Model with nTimeStep=100 would
>  be run well but whenever I increase it for more times I
>  encounter with the following error:
>
>
>
>  ABNORMAL END: S/R MON_SOLUTION, stops due to EXTREME
>  Pot.Temp
>
>
>
>  My error in STDER.0000 is:
>
>  (PID.TID 0000.0001) SOLUTION IS HEADING OUT OF BOUNDS:
>  tMin,tMax=-1.918+101  1.617+101
>
>  (PID.TID 0000.0001)  exceeds allowed range
>  (monSolutionMaxRange= 1.000E+03)
>
>  (PID.TID 0000.0001) MON_SOLUTION: STOPPING CALCULATION at
>  Iter=  20
>
>  (PID.TID 0000.0001) ***ERROR***S/R ALL_PROC_DIE: ending the
>  run
>
>
>
>  Of course, once I used startTime and endTime instead of
>  nTimeStep but it didn't matter.
>
>
>
>  My data file is as following:
>
>   nIter0=0,
>
>   nTimeSteps=8640,
>
>   deltaT=50,
>
>   dumpFreq=21600,
>
>   pChkptFreq=0,
>
>   chkptFreq=0,
>
>   monitorFreq=2500.,
>
>   periodicExternalForcing=.TRUE.,
>
>   externForcingPeriod=2592000.,
>
>   externForcingCycle=31104000.,
>
>   tauThetaClimRelax=31104000.,
>
>   abEps=0.02,
>
>   &
>
>
>
>  Is it possible that my domain is big for internal wave
>  analysis that I get that error? if not so, how can I fix
>  this problem? how can I run model for 4 years and more with
>  this situation?
>
>
>
>  Thank you in advance for any help,
>
>  Saeid
>
>
>
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