[MITgcm-support] EmPmRfile, EmPmR

[Dmitri Leonov]

A recent version of CONFIG_CHECK told me that nonlinFreeSurf cannot be 
used without exactConserv.

Matthew Mazloff wrote:
> 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).