[MITgcm-support] Re: viscosity questions

[Baylor Fox-Kemper]

Hi Martin,
    At 900m or 300m, you probably should be using Smagorinsky, not  
Leith.  Leith is really only appropriate for the gridscales in the  
range where one expects the E(k) \propto k^-3 inverse cascade (i.e.,  
above the deformation radius).  Unless your gulf is quite  
unstratified, you should be well below the deformation radius, where  
you will expect a E(k) \propto k^-5/3 scale, and Smagorinsky is the  
appropriate scaling for that.
    You could try either c2smag or c4smag or both.
    As far as diffusivities are concerned, are you seeing noise in  
T&S but not in U&V?  What about in density?  Also, are you seeing  
noise near topography (I note you have jamartwetpoints off)?
    Also, I see you have cadjfreq off, so are you using KPP?  If you  
are, it will certainly generate gridscale noise during convective  
events.  You can reduce this by using the "smooth" settings in  
KPP_OPTIONS.h.
    I hope that helps.
       -Baylor


On Nov 16, 2006, at 12:14 PM, Martin Losch wrote:

> <data>