[MITgcm-support] pressure from MITgcm

[Sergey Vinogradov]

Hi folks!

Did anyone compare the pressure profiles computed from hydrostatic 
anomaly ('PH' output) and from density?  
I'm using atm. loading with MITgcm. In order to compute the full 
pressure at the center of k-th layer, I can either get it from T and S 
through density: p (rho) = rho0*g*eta + g* J (rho*dz), or, use the PH 
output (phiHydC variable), which, according to previous correspondence 
with Martin and Dimitris, can also give me the full pressure (at k-th 
layer):
p (PH) = rhoConst*PH(k) + g*rhoConst*D(k)
Notations are: rho0 - surface density; g-gravity; eta-full sea-surface 
elevation; dz-layer thicknesses; rhoConst - reference density; D - 
central depths of layers; J - integral from cell center depth to the 
surface.
I get different variability from these two methods (see attached 
fragment of timeseries sampled at some layer). Other than the difference 
in eos that I use for density computations, what may be the reason for 
discrepancy in the variability between these two pressure computations? 
Am I missing something?

Thanks,

-- 
Sergey Vinogradov, Ph.D.
Oceanography Group
Atmospheric and Environmental Research, Inc.
131 Hartwell Ave., Lexington, MA 02421, USA
Phone:  1-781-761-2256       sergey at aer.com
Fax:    1-781-761-2299   http://www.aer.com

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