[MITgcm-support] Set a density distribution

[Ryan Abernathey]

Serge,

What Matt described is what many of us do in idealized setups where we  
don't care about T & S individually but only about buoyancy in  
general. Specifically, I use the following options in my data file.

eosType='LINEAR',
tAlpha=2.0E-04,
sBeta=0.,
saltStepping = .false.,

Then the buoyancy is defined as
gravity * tAlpha * THETA

You can set an initial buoyancy just by setting an initial  
temperature. In your data file, this would look like
  &PARM05
  hydrogThetaFile='myHydrogThetaFile.bin',
  &

-Ryan

On Apr 18, 2011, at 5:35 PM, Matthew Mazloff wrote:

> Hi Serge,
>
> You cannot just set density -- as you stated, T and S are the state  
> variables used by the MITgcm.  If you are running an idealized  
> experiment, however, you can just turn off salinity stepping  
> (saltStepping = .false., in data PARM01)  and just use T making your  
> equation of state linear such that T and rho will be analogous.
>
> -Matt
>
>
> On Apr 18, 2011, at 2:06 PM, fancer fancer wrote:
>
>> Matt,
>>
>> I mean dynamics density, but for initial conditions.
>> I mean can I set a matrix with 3D density profile of my area,  
>> instead of setting T and S at initial time?
>> If I understand your answer properly, I can not.
>> I looked the equations of model and understood what it is impossible.
>> Every time calculates T and S  through the special equations. Then  
>> density calculates through EOS and desity goes to equation of motion.
>> MITgcm do not have a equation for  evolution of density. But if it  
>> has, it can be possible. Right?
>>
>> Sincerely,
>> Serge Semin
>>
>>
>> On Tue, Apr 19, 2011 at 12:34 AM, Matthew Mazloff  
>> <mmazloff at ucsd.edu> wrote:
>> Hi Serge,
>>
>> Do you mean reference density or dynamics density.
>>
>> Dynamic density is not  a model input, but instead calculated from  
>> T and S using one of the equation of state (EOS) options.  Some of  
>> the EOS have matlab equivalents in
>> http://mitgcm.org/viewvc/MITgcm/MITgcm/utils/matlab/
>>
>> Reference density is taken as a constant, and should not be  
>> spatially varying....
>>
>> -Matt
>>
>>
>>
>> On Apr 18, 2011, at 12:18 PM, fancer fancer wrote:
>>
>>> Hi, MITgcm support.
>>>
>>> How can I set a density distribution for my computational area?
>>> I know about rhoRefFile input parameter, but this is a 1D vector,  
>>> where each element for one vertical layer.
>>> I have a 3D matrix with density profile for my area.
>>> Is there are some special input parameters or method for  
>>> integrating it into computational area?
>>>
>>> In advance thanks for help.
>>>
>>> Sincerely,
>>> Serge Semin
>>> <ATT00001.txt>
>>
>>
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>>
>> <ATT00001.txt>
>
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