[MITgcm-support] KPP diffusivities

[squerin at ogs.trieste.it]

Hi Dimitris and Martin,
first of all, thanks for your suggestions!
I didn't add many details to the first mail to be as synthetic as possible.
By the way, some colleagues also suspected that those "strange" diffusivities 
could be due to some daily bottom currents: however, at least at first sight, 
those peaks did not seem to be correlated with bottom velocities (which are 
also very very small, expecially before the wind event). It must be pointed 
out that the model is nested into a larger one but does not include tidal 
forcing (here, the most relevant tidal components are diurnal and semi-
diurnal). I also made a run with constant (no daily cycle) sw flux: the result 
was a constant turbulence intensification at the bottom! So, the "anomaly" 
really seems to directly depend on the sw flux. I will surely try to recompile 
and re-run the model to definitely exclude the shear instability hypothesis.

Martin, maybe the KPP scheme can't be applied to such a kind of configuration 
(I hope it can, also because I think that vertical variability in turbulence 
parameters can be very useful to my studies...). Actually I'm always running 
the model in non-hydrostatic mode: the timestep is really small (10 s) and I 
can simulate 1 day in 1 hour with 4 AMD 64 Opteron processors (using more CPUs 
I encountered severe limitations in the scalability...).

Again, thanks a lot!

Cheers,

Stefano

-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/