[MITgcm-devel] conservation Problem with KPP viscosity

[Dimitris Menemenlis]

Jean-Michel, any more ideas about this KPP conservation problem.  From your 
description below it sounds like problem is not caused by KPP itself but by some 
inaccuracy with time-stepping scheme in the presence of large, spatially varying 
vertical viscosities ???

> Seems that the problem a conservation of T & S in the donuts
> is related to KPP viscosity:
> When I comment out CALL KPP_CALC_VISC in calc_viscosity.F,
> I get a good conservation of T (~1.e-5 J/m2) and S (~1.e-8 g/m2),
> over 1 year, which is what I expect given the machine precision.
> On the contrary, with KPP-viscosity on, the drift in T & S are
> still small ( ~1 J/m2 & ~1.e-5 g/m2) over the same period,
> but much larger than what they should be.