[MITgcm-support] model keeps losing kinetic energy

[David Wang]

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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