[Mitgcm-support] RE: GMredi SmallNumber

[mitgcm-support at dev.mitgcm.org]

Patrick,

 P.S. I think the zero values for sigma_x are for
points that fall between two vertical walls.

Chris

-----Original Message-----
From: Jean-Michel Campin [mailto:jmc at gulf.mit.edu]
Sent: Monday, March 04, 2002 10:09 AM
To: support at mitgcm.org
Cc: jmc at gulf.mit.edu
Subject: GMredi SmallNumber


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