[MITgcm-support] Re: viscosity questions

[Jean-Michel Campin]

Hi Martin,

Looks like an interesting problem !
No obvious noise on uVel,vVel. What about wVel ?
Also, the noise on T,S, is it a steady noise or oscillating/fast-growing ?

I did not use very often this option, but you can try to
keep the 33 advection scheme for the horizontal, and switch back
to 2nd order in the vertical (at least for a test):
 tempAdvScheme=33,
 tempVertAdvScheme=2,

Jean-Michel

On Thu, Nov 16, 2006 at 11:34:32PM +0200, Martin.Losch at awi.de wrote:
> Hi, 
> thanks for the KPP suggestion. However, I never had any problems with KPP, and this time again, KPP is not the culprit. I 
> turned it of (use cAdjFreq=-1) and the problem persists.
> 
> Again: 
> with temp/saltAdvScheme = 2 and diffK4T/S = 1.e6, I can suppress the noise, but
> with temp/saltAdvScheme = 33 and diffK4T/S = 1.e6, there is a lot of noise (also with diffK4T/S smaller or 0), 
> staggerTimeStep = .true.. That's what's really puzzling me. I though that the advection scheme 33 (DST3FL) is extremely 
> stable and should remove all grid scale noise (in my previous experience it does exactly that). Why not now?
> 
> Martin
> 
> Martin Losch
> Alfred Wegener Institute 
> Postfach 120161, 27515 Bremerhaven, Germany; 
> Tel./Fax: ++49(0471)4831-1872/1797
> 
> 
> 
> ----- Original Message -----
> From: Dimitris Menemenlis <menemenlis at sbcglobal.net>
> Date: Thursday, November 16, 2006 9:09 pm
> Subject: Re: [MITgcm-support] Re: viscosity questions
> 
> > KPP does have a computational grid-scale mode in T/S, especially 
> > visible at 
> > Equator, in my experience.  That's why those horizontal 121 filters 
> > were added. 
> >  The recommended filters are on by default in KPP_OPTIONS.h.  But 
> > worth trying 
> > with KPP off.  D.
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mitgcm.org/mailman/listinfo/mitgcm-support
> > 
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support