[Mitgcm-support] GMredi SmallNumber

[mitgcm-support at dev.mitgcm.org]

Hi Patrick,

Some order of magnitude:
In one global ocean run, with annual mean forcing (restoring, Levitus)
at equilibrium, the global average vertical profile of N2 
indicates values of the order of 10^(-6.6) below 2.5 km.
With N2 = -sigma_z * g / rho0 , the average value of 
-sigma_z in this run is of the order of 25.e-6 kg/m4 below 2.5km.

Since 
1) region where the slope is larger than the maximum slope are 
   generally found near the surface, in the mixed layer, but not 
   often in the deep ocean (=> |sigma_x,y| < -sigma_z * Smax)
2) 25.e-6 is an average, but can be smaller or larger in some region.
I expect that SmallNumber = 1.e-6 can make some differences, 
probably small changes I guess.

See you,

Jean-Michel