[MITgcm-support] convertEmP2rUnit

[Martin Losch]

Jean-Michel, Alistair,

Steve Griffies suggested replacing rhoConstFresh by the actual insitu 
fresh water density (which could be computed according to the used 
EOS). Otherwise I don't have any new suggestions, so it's probably a 
good idea to use Jean-Michel's new definition of convertEmP2rUnit. As 
far as I remember we have thought about that last year, too, but 
somehow dismissed it.

It would be interesting to see whether this improves the fit between 
Boussinesq and non-Boussinesq model, but I don't dare to have a look (o:

Martin

On Friday, November 14, 2003, at 03:20  PM, Alistair Adcroft wrote:

> I think the next time I hear about horizVertRatio I'll scream; your 
> point is
> well taken that a consistent conversion is necessary and some 
> flexibility
> and intellegence on the models part is necessary. However, 
> horizVertRatio is
> a historical left-over from the strictly p-coordiante days which I 
> wanted to
> eliminate when I first implemented r-coordinates but some cry babies 
> cried;
> it is currently a proxy for dr/dz and this is exactly the factor you 
> are
> looking for when converting FW to r-dot. Yet another thing to flag for 
> tidy
> up.
>
> A.
> --
> Dr Alistair Adcroft            http://www.mit.edu/~adcroft
> MIT Climate Modeling Initiative        tel: (617) 253-5938
> EAPS 54-1523,  77 Massachusetts Ave,  Cambridge,  MA,  USA
>
> -----Original Message-----
> From: mitgcm-support-bounces at mitgcm.org
> [mailto:mitgcm-support-bounces at mitgcm.org] On Behalf Of Jean-Michel 
> Campin
> Sent: Thursday, November 13, 2003 7:45 PM
> To: mlosch at awi-bremerhaven.de
> Cc: mitgcm-support at mitgcm.org
> Subject: [MITgcm-support] convertEmP2rUnit
>
>
> Hi Martin,
>
> I think that convertEmP2rUnit should be:
>  convertEmP2rUnit = rhoConstFresh*recip_rhoConst*horiVertRatio
> and not:
>  =1. [if ocean-Z]
>  =rhoConstFresh*Gravity [if ocean-P]
> as it is now.
>
> The result is the same for ocean-P since 
> horiVertRatio=rhoConst*Gravity in
> this case (and horiVertRatio=1 in ocean-Z).
>
> My point is:
> if we think that a different rhoConst for Fresh water
> is needed in the ocean-P, then it seems logical to have the same 
> ability in
> ocean-Z.
>
> The reason why I ask this is that I started to use rhoConstFresh
> for the density of the fresh water with sea-ice component
> and with atmospheric model, and cannot reach a perfect
> conservation unless I set rhoConstFresh=rhoConst, simply because 
> presently
> convertEmP2rUnit=1. whatever rhoConstFresh/rhoConst is.
>
> What do you think ?
>
> Jean-Michel
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