[MITgcm-support] MITgcm-support Digest, Vol 144, Issue 16

[Dustin Carroll]

Hi Pu,

How quickly does the solution diverge — did you try decreasing your deltaT and seeing where the model blows up? 
Also, what are you prescribing at your open boundaries — are you balancing net flow? 

Dustin

> On Jun 30, 2015, at 12:03 PM, guopu at scsio.ac.cn wrote:
> 
> Hi Dustin,
> 
> My data.obcs file is:
> 
> &OBCS_PARM01
> OB_Iwest=1,
> OB_Ieast=-1,
> 
> &
> 
> My data file is:
> 
> # Continuous equation parameters
>  &PARM01
>  sRef=200*35.,
>  viscAh=1.E-2,
>  viscAz=1.E-3,
>  no_slip_sides=.FALSE.,
>  no_slip_bottom=.FALSE.,
>  diffKhT=1.E-2,
>  diffKzT=1.E-3,
>  f0=0.0,
>  beta=0.E-11,
>  eosType='LINEAR',
>  tAlpha=2.E-4,
>  sBeta =0.E-4,
>  gravity=9.81,
>  implicitFreeSurface=.TRUE.,
>  exactConserv=.TRUE.
>  nonHydrostatic=.FALSE.,
>  hFacMin=0.2,
>  implicSurfPress=0.5,
>  implicDiv2DFlow=0.5,
>  nonlinFreeSurf=3,
>  hFacInf=0.2,
>  hFacSup=1.8,
> saltStepping=.FALSE.,
>  readBinaryPrec=64,
>  writeBinaryPrec=64,
>  writeStatePrec=64,
>  &
> # Elliptic solver parameters
>  &PARM02
>  cg2dMaxIters=1000,
>  cg2dTargetResidual=1.E-13,
>  cg3dMaxIters=400,
>  cg3dTargetResidual=1.E-13,
>  &
> # Time stepping parameters
>  &PARM03
>  nIter0=0,
>  nTimeSteps=50,
>  deltaT=30.,
>  abEps=0.1,
>  pChkptFreq=0.,
>  chkptFreq=0.,
>  dumpFreq=120.,
>  monitorFreq=2500.,
>  monitorSelect=2,
>  &
> # Gridding parameters
>  &PARM04
>  usingCartesianGrid=.TRUE.,
>  delXfile='dx.init',
>  delYfile='dy.init',
>  delZ=200*10.,
>  &
> # Input datasets
>  &PARM05
>  hydrogThetaFile='T.init',
>  bathyFile='topog.box',
>  uVelInitFile = 'U.init', 
>  &
>  
> 
> The output T and U is like the initial state set by T.init (from 13 to -13℃ vertically) and U.init (0.1m/s all over the domain), but their max values increase rapidly after 480s. At 600s the max T is 1E4℃ and U is 120m/s, at 720s they are 8E32℃ and 8E27m/s.
> 
> I turn on some other flags in data.obcs and try many times, but the results are always odd.
> 
> Pu
> 
> 
> 
> 
> > 
> > Hi Pu,
> > 
> > Yes, you set your open boundaries  in data.obcs as
> > 
> >  OB_Iwest  =   1,
> >  OB_Ieast  =   -1,
> > 
> > and your IC for u velocity in your data file under &PARM05 as
> > 
> > uVelInitFile = ?U.init?
> > 
> > Can you describe what looks wrong with your model output?
> > 
> > Dustin
> > 
> > > On Jun 29, 2015, at 2:08 PM, guopu at scsio.ac.cn wrote:
> > > 
> > > Hi there,
> > > 
> > > I am building a simple 2D model: a constant flow (U) over a seamount. Now I generate the topography and stratification, but don't know how to set the east and west open boundary. Is it simply to set "OBCS_Iwest=1" and "OBCS_Ieast=-1" in file data.obcs ? I did it but the result is odd. I make a 3D velocity file "U.init" and then use: uVelInitFile = 'U.init' to set the initial and constant zonal horizontal velocity. I think I did something wrong....
> > > 
> > > By the way, thank Gus Correa for answering my question about netcdf, I don't know how to reply you directly. I did with '-lnetcdff -lnetcdf'  as you said, but it still did not work.  I hope it works, but Dimitris Menemenlis is right, netcdf is not necessary.
> > > 
> > > Pu
> > > 
> > > 
> 
> 
> 
> 
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