[MITgcm-support] 回复: How to calculate the phiHyd (hydrostatic pressure potential anomaly) with model output ?

[Mike Fan]

Hi Martin,

You are right (rhoNil is \rho_c, rhoConst is \rho_0), thank you very much!

Cheers

·¢¼þÈË: Martin Losch<mailto:Martin.Losch at awi.de>
·¢ËÍʱ¼ä: 2022Äê10ÔÂ10ÈÕ 16:51
ÊÕ¼þÈË: MITgcm Support<mailto:mitgcm-support at mitgcm.org>
Ö÷Ìâ: Re: [MITgcm-support] How to calculate the phiHyd (hydrostatic pressure potential anomaly) with model output ?

Hi,

there are couple of constant ¡°rho¡±s in the code, e.g. rhoConst, rhoNil, rhoConstFresh, which all have a default, which can be changed. I usually check, which value the model actually uses (because I always forget, how the defaults are determined), in the stanard output (or in an MPI run in STDOUT.0000).

For the EOS calculation, checkout how ¡°find_rho_2d¡± (in find_rho.F) does it: it uses ¡°rhoNil¡± to scale the density (this should be ¡°\rho_c¡±, while rhoConst = ¡°\rho_0¡±). I am not sure if the 1D field rhoRef is used in this context.

Hope this helps,

Martin


On 7. Oct 2022, at 08:39, Mike Fan <ifanliming at outlook.com<mailto:ifanliming at outlook.com>> wrote:

Hello all,

I want to use the model output (temp & salt & eta) to calculate the phiHyd, Through reading the guidebook, I learned that phiHyd is called hydrostatic pressure potential anomaly, using the equation like 4.2. Baroclinic Ocean Gyre ¨D MITgcm checkpoint68k-6-g80404458a documentation<https://mitgcm.readthedocs.io/en/latest/examples/baroclinic_gyre/baroclinic_gyre.html#output-files>.

In my model, setting a linaer EOS, implicitFreeSurface=¡¯true¡¯, and rhoConst=999.8. Here is my question, there is a rho_0, how the model calculates it?

What I have done. I set rho_0=rhoref (got from RhoRef.data & RhoRef.meta), but the result is not the same as the phiHyd (got from phiHyd.00000******.t0**.nc).


Leming
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