[MITgcm-support] RE: diapycnal mixing in GM/Redi

[mdp1 at soc.soton.ac.uk]

Hi Chris.

Can you tell me how the diapycnal mixing is determined in the GM/Redi package? 
Is it possible to choose different values for this parameter?

Thanks,

Matt

Quoting Chris Hill <cnh at mit.edu>:

> Hi matt,
> 
>  in the situation you describe gad_diff_r is not used or needed. With gm
> active the vertical k can become large because it includes a project of the
> along iso surface horizontal diffusivity and bolus transport. Therefore in
> the mode where gm is active implicit vertical diffususion should/is always
> be used.
> 
>  Does that make sense?
> 
> chris 
> 
> > -----Original Message-----
> > From: mitgcm-support-bounces at mitgcm.org 
> > [mailto:mitgcm-support-bounces at mitgcm.org] On Behalf Of Matt Palmer
> > Sent: Tuesday, August 03, 2004 12:17 PM
> > To: mitgcm-support at mitgcm.org
> > Subject: [MITgcm-support] "gad_diff_r.F" and mixing
> > 
> > Hi there.
> > 
> > I've been doing model runs using the GMRedi package and 
> > combining a 3-D vertical mixing field. When I compare the 
> > model overturning (the Indian
> > Ocean) using GMRedi and vertical mixing, the result is much smaller (2
> > Sv) than for the same vertical mixing field and 
> > horizontal/vertical mixing (16 Sv).
> > 
> > While looking into this discrepency I found that 
> > "gad_diff_r.F" was not being called from "gad_calc_rhs.F". It 
> > seems that if "gad_diff_r.F" is not called, it's because the 
> > model is using implicit diffusion. Can someone tell me 
> > whether "gad_diff_r.F" should be routinely called when using 
> > vertical mixing?
> > 
> > Many thanks,
> > 
> > Matt Palmer
> > 
> > 
> > _______________________________________________
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> > MITgcm-support at mitgcm.org
> > http://dev.mitgcm.org/mailman/listinfo/mitgcm-support
> > 
> 
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> 


-- 
Matt Palmer 
School of Ocean and Earth Science
University of Southampton
Southampton Oceanography Centre
European Way
S014 3ZH 
United Kingdom
tel: +44 (0)23 80596130
email: mdp1 at soc.soton.ac.uk