[MITgcm-support] nTimeStep

[Jody Klymak]

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

   1. setting `hFacMin` to be too small value can mean your vertical 
cell is very small, and the 
[CFL](https://en.wikipedia.org/wiki/Courant–Friedrichs–Lewy_condition) 
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.
   2. 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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