[MITgcm-support] Re: Problems with Leith

[Alistair Adcroft]

Raf,

In our usual fashion we added Leith as a test of user abilities. Included with
Leith is the special feature that if you are not using
vectorInvariantMomentum=.true. (in PARM01) then the model fails to tell you
that you can't (yet) use Leith with the conservative form of the momentum
equations. So far no users have passed the test. :-)

Switching to vector invariant equations should fix this behaviour.

A.

Quoting Raffaele Ferrari <rferrari at MIT.EDU>:

> Dear Alistair,
> 
> how is life in Princeton? Do you miss MIT and the long commute?
> 
> We (Baylor and I) have a question about the Leith viscosity. We are 
> trying to switch to Leith the run of the high-res front for the CPT. We 
> compared a low res run with a constant biharmonic viscosity with an 
> equivalent run with Leith (biharmonic, vector-invariant form). We set 
> the Leith constant (ViscC4Leith) to be 0.1 and 1 (and 5e7 by mistake). 
> We find that the Leith runs are stable but with a lot of grid-scale 
> noise, no matter what the dimensionells constant is. Are we doing 
> something wrong?
> 
> Thanks,
> Raf
>