[MITgcm-support] model keeps losing kinetic energy

[David Ferreira]

Hi David,
I am not convinced your KE mean plot is suspicious.
(BTW, does it display 10 or 100 years ?)
Anyway, I've got coupled runs where the mean KE drifted for
1000s of years (see the fig). I guess that if baroclinic currents
make a significant contribution to the KE, KE is going to drift
with the stratification until vertical diffusion has done its job.
david

David Wang wrote:
> Hi there,
>
> I'm bothered with a 100-year spin-up of an intermediate resolution 
> (about 1x1), near global ocean, with a recent version of MITgcm, which 
> keeps losing kinetic energy (momKE_ave by the way of diagnostics pkg). 
> I have a rather simple setup with horizontal bi-harmonic viscosity, 
> KPP vertical viscosity, no slip bottom and free slip side, as well as 
> asynchronous time stepping for momentum and tracers (see also the 
> attached "data" namelist). GMREDI pkg is also used. The surface 
> mechanical condition is climatological monthly wind stresses from da 
> Silva et al (1994), and the surface buoyancy condition is simply 
> SST/SSS relaxation to their monthly climatologies. The model started 
> from the rest and climatological temperature/salinity. I've attached a 
> plot of the global-mean KE which shows a clear downward trend. 
> However, I expect, in principle, the global-mean KE will be stabilized 
> after a few decades at most. I checked the wind stress diagnostics 
> (oceTAUX, oceTAUY) which do the correct job forcing the ocean year 
> after year with the same seasonal cycle. The model does have a 
> reasonable general ciculation. But the leaking KE is disturbing to me 
> and makes me doubt the integrity of the run. Since I only have limited 
> computational resouce, I'd like to see if anyone out there may have a 
> guess what could go wrong with my model run.
>
> Thank you!
> David
>
> -- 
> life grows, death doesn't.
>
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