[MITgcm-support] phihydlow formula

[Benny Cheng]

Thanks Martin. I'm more interested in whether some land masking is
applied to the integral or not, since Ichiro thinks it's a "bug" without
it. Dimitri already replied that it was masked. The way it's done in the
code is rather complicated (min ,max , ddrloc ,rec_drm, drlocm), and if
it is equivalent to hfacc, why not just use it? perhaps not...
- Benny 

On Tue, 2004-08-17 at 00:01, Martin Losch wrote:
> Benny,
> the formulae are all in the documentation, so equation 1.32 on that 
> page is it. As I wrote in my previous email to the other thread, for 
> height coordinates, b in 1.32 is the scaled density g\rho/\rho_{0}. In 
> the code it's actually the scale density anomaly, as Dimitris pointed 
> out: g(\rho-\rho_{0})/\rho_{0}, so the phiHyd and phiHydLow is the 
> corresponding pressure anomaly scaled by \rho_{0}. If you compute the 
> full bottom pressure (including the g\rho_{0}H contribution), then you 
> won't see much except topography. Because topography (=depth) dominates 
> the bottom pressure, it really only makes sense to look at fluctuations 
> of bottom pressure. and for those the choice of \rho_{0} (=rhoConst in 
> data) is irrelevant.
> 
> There is a paper by John Marshall which also should have all the 
> formulae:
> Marshall, J. A. Adcroft, J-M Campin and  C. Hill (2004)
>   Atmosphere-ocean modeling exploiting fluid isomorphisms. submitted to  
> Monthly Weather Review. You can download a preprint from
> http://paoc.mit.edu/paoc/marshall/latest_papers.htm
> Also in Losch etal 2004 JPO 34(1), pp 306-319, we describe the 
> ismorphism and all equations in detail in the appendix (in particulare 
> Eq A23 and the following text). Appendix C describes the discretization 
> issue I was alluding to earlier. If you don't have access to JPO, you 
> can download a preprint from
> http://mitgcm.org/~mlosch/nonbouss_pp.pdf
> 
> Good luck,
> Martin
> 
> On Aug 16, 2004, at 11:54 PM, Benny Cheng wrote:
> 
> > Could someone show me or email me the exact phihydlow computation ( in
> > mathematical notation , not code) used in the MITgcm. It looks rather
> > murky to tread through the code... is it close to what is described in
> > http://mitgcm.org/sealion/online_documents/node20.html ? thanks.
> >
> > - Benny
> >
> >
> >
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> >
> Martin Losch // mailto:mlosch at awi-bremerhaven.de
> Alfred-Wegener-Institut für Polar- und Meeresforschung
> Postfach 120161, 27515 Bremerhaven, Germany
> Tel./Fax: ++49(471)4831-1872/1797
> http://www.awi-bremerhaven.de/People/show?mlosch
> 
> 
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