[MITgcm-support] Effect of 'vectorInvariantMomentum' flag on first order circulation

[Dhruv Balwada]

Hello everyone,

Thanks for the quick responses.

@ Jean-Michel I will follow your suggestions and report back on them soon.

Best,
Dhruv


On Mon, Feb 27, 2017 at 3:56 PM, Jean-Michel Campin <jmc at mit.edu> wrote:

> Hi Dhruv,
>
> It's a strange results. Both pkgs (mom_fluxform and mom_vecinv) have been
> tested and used in many different configs, and no significant recent
> changes
> that would be suspicious.
>
> I suggest to try to work on a short test run:
> 1) long enough to detect some significant differences between the 2 cases:
>   vectorInvariantMomentum=T and = F
> 2) short enough so that the same 2 runs could be repeated with zero
> compiler
>  optimization (-ieee or -devel with many standard optfile).
> And from there, we could work on trying to reproduce the problem on
>  different machine/compiler ... etc.
> Once we are able to reproduce the problem, should not take too long to fix.
>
> Cheers,
> Jean-Michel
>
> On Thu, Feb 23, 2017 at 02:58:53PM -0500, Dhruv Balwada wrote:
> > Hi MITgcm community,
> >
> > I have recently been stumped an issue with the MITgcm
> vectorInvariantMomentum
> > flag.
> >
> > **The model setup** is meant to be an ideal representation of the ACC
> > (following Abernathey and Cessi 2014). It has the following components -
> > a) Linear temperature relaxation at the surface
> > b) Zonal wind with sinusoidal structure
> > c) Initial temp field is zonally symmetric and the thermocline shoals
> from
> > north to south (similar to the ACC).
> > d) Resolution is 20km, and domain size is 2000km * 2000km.
> > e) Zonally periodic and meridional walls
> > f) A zonal gaussian bump is the topographic feature, which is meridionaly
> > independent.
> >
> > **The issue** I am facing is that the circulation pattern completely
> > changes when I change the "vectorInvariantMomentum" flag.
> > When the flag is set to false (default), the model recreates an ACC like
> > flow. Flow is from west to east and strongly perturbed by the presence of
> > topography.
> > When the flag is set to true (default), the model does something else.
> Flow
> > is from east to west, with a strong boundary flow from the west to east
> > near the southern boundary.
> >
> > Any help would be appreciated.
> >
> > I have posted some visualizations and data file here -
> > https://sites.google.com/site/dhruvbalwada/blog/
> mitgcmissuewithvectorinvariantmomentumflag
> >
> > Here is the data file (obviously the vectorinvariantmomentum flag is
> > changed between two runs.
> >
> >  &PARM01
> >
> > # viscosity
> >
> >  viscAr=5.6614E-04,
> >
> >  viscC4Leith=2.15,
> >
> >  viscC4Leithd=2.15,
> >
> >  viscA4GridMax=0.8,
> >
> >  useAreaViscLength=.TRUE.,
> >
> >  highOrderVorticity=.TRUE.,
> >
> > # diffusivity
> >
> >  tempAdvScheme=7,
> >
> >  diffKrT=5.44e-7,
> >
> >  saltStepping=.FALSE.,
> >
> >  staggerTimeStep=.TRUE.,
> >
> > # multiDimAdvection=.TRUE.,
> >
> >  vectorInvariantMomentum=.TRUE.,
> >
> > # initial vertical profiles of T and S
> >
> >  sRef=30*35.0000,
> >
> > # equation of state
> >
> >  eosType='LINEAR',
> >
> >  tAlpha=2.0E-04,
> >
> >  sBeta=0.0,
> >
> > # boundary conditions
> >
> >  no_slip_sides=.FALSE.,
> >
> >  no_slip_bottom=.TRUE.,
> >
> > # bottomDragLinear=1.1E-03,
> >
> >  bottomDragQuadratic=0.0021,
> >
> > # physical parameters
> >
> >  f0=-0.9E-04,
> >
> >  beta=1.0E-11,
> >
> >  gravity=9.81,
> >
> > # implicit diffusion and convective adjustment
> >
> >  implicitDiffusion=.TRUE.,
> >
> >  implicitViscosity=.TRUE.,
> >
> > # exact volume conservation
> >
> >  exactConserv=.TRUE.,
> >
> > # C-V scheme for Coriolis term
> >
> >  useCDscheme=.FALSE.,
> >
> > # partial cells for smooth topography
> >
> >  hFacMin=5.0E-02,
> >
> > # file IO stuff
> >
> >  readBinaryPrec=64,
> >
> >  useSingleCpuIO=.TRUE.,
> >
> >  debugLevel=1,
> >
> >  &
>
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
>
>
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