[Mitgcm-support] RE: advection schemes

[mitgcm-support at dev.mitgcm.org]

What is Olx,Oly set to? Does this happen with schemes=3?

A.

> -----Original Message-----
> From: Martin Losch [mailto:mlosch at awi-bremerhaven.de]
> Sent: Thursday, May 08, 2003 10:03 AM
> To: support at mitgcm.org
> Subject: Re: advection schemes
> 
> 
> Alistair,
> 
> my set-up is still in the toy-phase, so I have 20x20x10 points with
> 25kmx25kmx500m. My initial stratification is such (similar to 
> Wardle and 
> Marshall N/f=21) that the Rossby radius is ~100km. After this initial 
> mixing event, this Radius has decreased to 50km and smaller, 
> that is, I 
> don't really resolve it anymore. So it's no longer high 
> resolution. But 
> shouldn't a zonally symmetric flow stay zonally symmetric forever, 
> regardless of the resolution?
> 
> Martin
> 
> support at mitgcm.org wrote:
> > The answer is it shouldn't happen so something is wrong.
> > 
> > Hope that helps!  :-)
> > 
> > Is this very high res.?
> > 
> > A.
> > 
> > 
> >>-----Original Message-----
> >>From: Martin Losch [mailto:mlosch at awi-bremerhaven.de]
> >>Sent: Thursday, May 08, 2003 8:37 AM
> >>To: support at mitgcm.org
> >>Subject: advection schemes
> >>
> >>
> >>Hi again,
> >>
> >>this time I have a question about advection schemes:
> >>I have replaced the default advection (2nd order, centered) by the
> >>DST-3 with flux limiter (temp/salt/tracerAdvScheme=33, by 
> the way, not
> >>very well documented which idenifying number belongs to which 
> >>scheme). In my channel, I start from a zonally homogeneous 
> >>(symmetric)
> state, with a
> >>strong vertical stratification (similar to Wardle and
> >>Marshall, 2000, JPO).
> >>
> >>I expect (and this is true for the 2nd centered scheme)
> that, starting
> >>from rest, I spinup my channel ad infinitum, until the CFL
> >>criterium is 
> >>violated the model explodes.
> >>
> >>With the DST-3 with flux limiter, this is NOT what happens, instead
> >>the whole system becomes unstable almost immediately (even 
> if I have
> >>some explicity bi-harmonic friction), I get deep mixing until the 
> >>channel is basically homogenized and then slowly the flow 
> >>restratifies according to
> >>my buoyancy forcing, but the zonal symmetry is broken 
> >>forever. Is that 
> >>supposed to happen?
> >>
> >>Martin
> >>
> >>--
> >>Martin Losch
> >>Alfred Wegener Institute for Polar and Marine Research Postfach
> >>120161, 27515 Bremerhaven, Germany;
> >>Tel./Fax: ++49(0471)4831-1872/1797
> >>
> >>
> > 
> > 
> 
> 
> --
> Martin Losch
> Alfred Wegener Institute for Polar and Marine Research
> Postfach 120161, 27515 Bremerhaven, Germany;
> Tel./Fax: ++49(0471)4831-1872/1797
> 
>