[MITgcm-support] [Fwd: MITgcm-support Digest, Vol 21, Issue 21]

Alistair Adcroft adcroft at mit.edu
Mon Mar 28 16:06:09 EST 2005


I just ran a pickup test on your set-up without Leith. Model state is 
not reproducable across pickups; based on a cursory look, it looks like 
W is not the same before and after a pickup. This might be 
z*/free-surface related so again let's ask J-M if it is meant to work?



Tom Haine wrote:
> Alistair, 
> Yes, I understand that no special pickup files are required for Leith.
> However, the code clearly diverges due to instability associated with
> the variable viscosity. For instance, setting: 
>  viscC4Leith=0.0,
>  viscA4GridMin=0.005,
>  viscA4GridMax=0.050,
> instead of:
>  viscA4Grid=0.,
>  viscC4Leith=1.0,
>  viscA4GridMax=0.005,
> allows the picked up calculation to survive for many more steps (before
> ultimately failing again). It seems that some aspect of the internal
> model state is different when picked up. This difference seems to cause
> a rapid divergence in the Leith scheme. Any ideas?
> Tom.
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Dr Alistair Adcroft            http://www.mit.edu/~adcroft
MIT Climate Modeling Initiative        tel: (617) 253-5938
EAPS 54-1624,  77 Massachusetts Ave,  Cambridge,  MA,  USA

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