[MITgcm-support] potential density

[Bruno Deremble]

Hi Matt,

I agree for drhodz. but what about sigmaX and sigmaY that are computed using rhoinsitu? (cf grad_sigma.F) I am probably misunderstanding the meaning of 'rhoinsitu' here.

Thanks 
bruno
 
> 
> Hi Bruno,
> 
> Not sure about (U,V,W)RHOMASS -- I would assume those are the  
> transport of in situ density since the model uses in situ density.
> 
> Derivatives of density (e.g. drhodz) are computed with a local  
> reference pressure -- so they are the gradient of potential (or  
> neutral) density. Therefore I believe sigmax and sigmay are the  
> gradients of pot. density.
> 
> -Matt
> 
> 
> 
> On Mar 22, 2011, at 6:20 AM, Bruno Deremble wrote:
> 
> > Good morning,
> >
> > In do_oceanic_phys, are sigmax and sigmay the gradients of 
> potential  
> > density (as stated in the manual in the gmredi section)? I ask 
> this  
> > because they are computed using 'rhoinsitu' which I presume is 
> the  
> > in situ density and not the potential density.
> >
> > in the diagnostic package WRHOMASS is associated to Vertical  
> > Transport of Potential Density whereas URHOMASS and VRHOMASS are 
> the  
> > horizontal transport of density. Is it correct in both cases?
> >
> > thank you
> > bruno
> >