[MITgcm-support] Turning off the ocean

[Chris Horvat]

Hey Jean-Michel,

I think this is because some large gradients develop in temperature, but
not totally sure.

However, momStepping=.FALSE. returns an error regarding the
variable storePhiHyd4Phys, which is not, as far as I can tell, accessible
via data.

In lieu of an immediate solution, I am instead running with

 momAdvection=.FALSE.,
 momViscosity=.FALSE.,
 momForcing=.FALSE.,
 useCoriolis=.FALSE.,
 useCDscheme=.FALSE.,
 momPressureForcing=.FALSE.,

which are all controlled by momStepping, so I will see if this gives a
better result.


---
Christopher Horvat -- www.chrv.at
PhD Student
School of Engineering and Applied Sciences
Department of Earth and Planetary Sciences
Harvard University
Cambridge, MA, USA



On Fri, Jan 13, 2017 at 3:08 PM, Jean-Michel Campin <jmc at mit.edu> wrote:

> Hi Chris,
>
> if you try:
>  momStepping=.FALSE.,
> in file "data", 1rst namelist ( PARM01 ), this will prevent any update of
> the velocity field that will remain the same as initial condition.
>
> If you prefer to prescribe a time-dependent velocity field then you could
> use pkg/offline (some doc in the manual & example:
> verification/tutorial_cfc_offline).
>
> There is no run-time switch to turn off active tracer (T,S) diffusivity
> other than to set various diffusivity coeff to zero.
> But by using:
> >  saltAdvection = .FALSE.,
> >  tempAdvection = .FALSE.,
> this should turn off the advection.
>
> I don't know why the model was becoming unstable, may be too large
> time-step
> relative to viscosity/diffusion/coriolis ?
>
> Cheers,
> Jean-Michel
>
> On Fri, Jan 13, 2017 at 01:07:23PM -0500, Chris Horvat wrote:
> > Hey all,
> >
> > I'd like to compare simulations with and without a dynamically active
> > ocean, but keeping the thermodynamic component. I've tried a couple of
> > methods that become unstable.
> >
> > First I tried:
> >
> >  saltAdvection = .FALSE.,
> >  tempAdvection = .FALSE.,
> >
> > Which has worked for me in the past, but now goes unstable. So then I did
> > some more digging, and now set.
> >
> > momForcing = .FALSE.,
> > momAdvection = .FALSE.,
> >
> > But this also goes unstable after a while. Is there a way to totally turn
> > off the ocean momentum equations? I am using KPP + Smagorinsky viscosity.
> > Haven't turned them off yet in these unstable simulations as I am nervous
> > that this might introduce new issues.
> >
> > Chris
>
> > _______________________________________________
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> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
>
>
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