[MITgcm-support] EmPmRfile, EmPmR

[Matthew Mazloff]

Hi Patrick,

I use real fresh water flux and do not use exact conserv and  
everything is fine.  The mean sea level does change and this is OK  
too.  The best way to do it would be to use non-linear free surface  
and turn off all salt flux....this is done by setting  convertFW2Salt  
= 0.,

I think you can also use  rhoConstFresh=1000. to set the density of  
the rain water...not sure..check in external_forcing_surf.F

-matt




On Mar 22, 2007, at 11:39 AM, Patrick Rosendahl wrote:

> Hi Martin,
>
> thanks! I use the non-hydrostatic formulation. I think you are  
> referring to this
> >> http://mitgcm.org/pelican/code_reference/vdb/code/167.htm#192_L
> section of the code, where the Temp & Salt is actually added in a  
> way that is correct for the rainy surface height increase. (Please  
> scroll up a few lines until you see the "#ifdef EXACT_CONSERV").
>
> Do you think I can change the code to execute it anyway (it is not  
> executed because of
> >> nonlinFreeSurf.GT.0 .OR. usingPCoords
> is false)?
> Additionally, I probably have to change the eta-code, so that the  
> rain is increasing the surface level. But I cannot find a good  
> place in the code to do it.
>
> best,
> Patrick
>
> Martin Losch wrote:
>> Patrick,
>> there is a flag called "useRealFreshWaterFlux", that makes the  
>> model  add volume to the topmost grid cell. I recommend to use it  
>> along with  exactConserv = .true. (you need to have the  
>> corresponding CPP flag  compiled with it). That should prevent  
>> your surface cells from  getting negative salinities.
>> If you feel really adventurous turn on the non-linear free  
>> surface  with r*-coordinates (global_ocean.cs32x15 has an example  
>> of this),  but that's not really required for the model use actual  
>> freshwater  flux (just makes is even more "physical" and stable  
>> for the kind of  forcing that you are trying to apply).
>> Martin
>> PS. the EmPmR variable is used always (with or without seaice,   
>> virtual salt flux or not).
>> On 22 Mar 2007, at 15:17, Patrick Rosendahl wrote:
>>> Hi!
>>>
>>> I want to simulate rain that actually increases the waterlevel.  
>>> If  I understand all the rain implementations in mitgcm, the rain  
>>> is  translated into a salt-flux. so after a while I will have  
>>> negative  salt values in the upper layer...
>>>
>>> model configuration is a closed water bassin that is partially   
>>> rained on. non-hs.
>>>
>>> I do not want to diagnose the aim package.
>>>
>>> best,
>>> Patrick
>>>
>>> Andrea Molod wrote:
>>>
>>>> hi patrick,
>>>> can you be a little more specific about what you mean?
>>>> what kind of model configuration, and what do you mean
>>>> by 'do rain'? a diagnostic for it in an aim package run?
>>>> something else? then maybe we can answer.
>>>> andrea
>>>> ----------------------------------------------------------------
>>>> Andrea M. Molod, PhD.
>>>> Department of Earth, Atmospheric & Planetary Sciences
>>>> MIT
>>>> Tel: (617) 253-5458, Email: amolod at mit.edu
>>>> WWW:http://paoc.mit.edu/paoc/people/person.asp?  
>>>> position=Postdoc&who=molod
>>>> ----------------------------------------------------------------
>>>> On Mon, 12 Feb 2007, Patrick Rosendahl wrote:
>>>>
>>>>> Hello all,
>>>>>
>>>>> the variable EmPmR is only used in the seaice and the   
>>>>> aim_compon_interf package, the web-sourcecode tells me.
>>>>>
>>>>> What is the best way to do "rain" (neglecting the vertical   
>>>>> velocities at the moment)?
>>>>>
>>>>> Best regards,
>>>>> Patrick Rosendahl
>>>>> _______________________________________________
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>>>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
>>>>>
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