[MITgcm-support] bottom pressure diagnostics

[Oliver Jahn]

Hi,

as far as I can tell, the surface contribution is added at the end of 
diags_phi_rlow.F.  HOWEVER, prior to cvs 2010-01-15, the vertical 
integral did not take the stretching of the column with nonlinFreeSurf=4 
into account, i.e., the diagnostic computed

   PHIBOT = gravity*ETAN + Depth/(Depth+ETAN) * gravity * \int 
(rho/rhoConst) dr

rather than

   PHIBOT = gravity*ETAN + gravity * \int (rho/rhoConst) dr

You may want to correct for this.

Oliver


On 2010-02-05 05:22, Jean-Michel Campin wrote:
> Hi Dimitris,
>
> I would assume the same thing as you.
> I will check when I am back from vacation.
> Cheers,
> Jean-Michel
>
> On Thu, Feb 04, 2010 at 08:33:07AM -0800, Dimitris Menemenlis wrote:
>> Jean-Michel, I will be very interested to hear your answer too.
>>
>> Martin, up to now, I have always assumed that PHIBOT is the bottom pressure,
>> specifically that PHIBOT in m^2/s^2 is the anomaly relative to Depth * rhonil * g
>> so that the absolute bottom pressure in Pa is:
>> Depth * rhonil * g + PHIBOT * rhonil
>>
>> 6-hourly output of ETAN and PHIBOT is available for cube78 and cub81
>> is available online and on skylla.
>>
>> Dimitris
>>
>> On Feb 4, 2010, at 8:00 AM, Martin Losch wrote:
>>
>>> Hi Jean-Michel (and Dimitris),
>>>
>>> we would like to cube78 or cube81 bottom pressure results. Can you confirm that for a time series of anomalies (in time) we need both PHIBOT and ETAN (for the linear free surface contribution):
>>>
>>> bottom pressure = gravity*rhoConst*ETAN + PHIBOT/rhoConst (+terms that are constant in time)
>>>
>>>  From looking at calc_phi_hyd I gather, that the non-linear free surface contribution etaH is only included, when selectRstar=0, which is not the case in cube78/81, correct? But in diags_phi_rlow, it says in the head that phi_hyd_rlow is actually bottom pressure. I am confused.
>>>
>>> Martin
>>>
>>>
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>>
>>
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