[MITgcm-support] Top boundary conditions

Fri Feb 5 17:37:51 EST 2010

Hello,
For the ocean gcm, is there a way to impose friction at the surface (no 
slip b.c.)?
Thanks for your help,
Georgy.

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> Today's Topics:
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>    1. Re: bottom pressure diagnostics (Jean-Michel Campin)
>    2. Re: bottom pressure diagnostics (Oliver Jahn)
>    3. Re: bottom pressure diagnostics (Oliver Jahn)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 5 Feb 2010 05:22:12 -0500
> From: Jean-Michel Campin <jmc at ocean.mit.edu>
> To: mitgcm-support at mitgcm.org
> Subject: Re: [MITgcm-support] bottom pressure diagnostics
> Message-ID: <20100205102212.GA28909 at ocean.mit.edu>
> Content-Type: text/plain; charset=us-ascii
>
> 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
>>>
>>>
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>       
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>     
>
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 05 Feb 2010 09:43:23 -0500
> From: Oliver Jahn <jahn at mit.edu>
> To: mitgcm-support at mitgcm.org
> Subject: Re: [MITgcm-support] bottom pressure diagnostics
> Message-ID: <4B6C2E8B.3080000 at mit.edu>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> 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
>>>>
>>>>
>>>> _______________________________________________
>>>> MITgcm-support mailing list
>>>> MITgcm-support at mitgcm.org
>>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>>         
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>       
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>     
>
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 05 Feb 2010 10:03:23 -0500
> From: Oliver Jahn <jahn at mit.edu>
> To: mitgcm-support at mitgcm.org
> Subject: Re: [MITgcm-support] bottom pressure diagnostics
> Message-ID: <4B6C333B.4060409 at mit.edu>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Sorry, it is the anomaly relative to Depth*rhoConst, of course,
>
> cvs prior to 2010-1-15:
>
> PHIBOT = gravity*ETAN + Depth/(Depth+ETAN) * gravity * \int 
> (rho/rhoConst - 1) dr
>
> should be:
>
> PHIBOT = gravity*ETAN + gravity * \int (rho/rhoConst - 1) dr
>
> Oliver
>
>
> On 2010-02-05 09:43, Oliver Jahn wrote:
>   
>> 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
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> MITgcm-support mailing list
>>>>> MITgcm-support at mitgcm.org
>>>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>>>           
>>>> _______________________________________________
>>>> MITgcm-support mailing list
>>>> MITgcm-support at mitgcm.org
>>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>>         
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>       
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>     
>
>
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> End of MITgcm-support Digest, Vol 80, Issue 3
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