[Mitgcm-support] FW: grid scale oscillations

[mitgcm-support at dev.mitgcm.org]

Dan,

 I'll do a survey of people here and see what they suggest. Meantime,
any pictures or thoughts on whether noise is related to steep topo.,
thin shaved cells or at open boundaries or something else etc.... Also
the values you have in data and data. files might give a clue -
especially lopping thresholds ( hFacMin etc...).

 Alistair - I remember Jake telling me that you had given him some fixes
to help with OBCS recently. 
 Jake (who is skiing this week) any comments? 

Chris
 
> -----Original Message-----
> From: Daniel Lea [mailto:daniel.lea at jhuapl.edu] 
> Sent: Wednesday, March 12, 2003 12:47 PM
> To: Chris Hill
> Subject: grid scale oscillations
> 
> 
> 
> Hi Chris,
> 
> I spoke too soon last week! I was working with a non shaved 
> cell version
> of the model I've switched to a shaved cell version and the grid scale
> oscillations are back. They are not strong and the model runs OK
> otherwise.
> 
> As I said my resolution is 1/6 zonal by 1/12 meridional. I've tried
> playing around with the vertical and horizontal (biharmonic) 
> diffusion and
> viscosity to no avail. Changing the advection scheme from 2nd 
> order to 4th
> order is not helpful. I haven't tried a flux limited scheme but don't
> think that would be good for the adjoint...
> 
> Should I smooth the topography somehow? (A very basic smoothing didn't
> help). What about conservation: E.g.  exactConserv or
> useEnergyConservingCoriolis?
> 
> Thanks
> 
> Dan
> 
> 
> 
>