[MITgcm-support] nonhydrostatic

Martin Losch Martin.Losch at awi.de
Fri Feb 23 07:52:46 EST 2007


Riema,

to turn on non-hydrostatic code you do exactly what you described.  
However, you can also set additional parameters for the cg3d solver  
(in analogy to cg2d), for example cg3dMaxIters, and  
cg3dTargetResidual, otherwise you'll use some defaults for those  
parameters (150 and 1e-7).

if (and only if) eosType = 'LINEAR', then
rho = rhoNil*(1-talpha*(theta-tRef) + sbeta*(salt-sRef))
default for rhoNil=999.8, but you can set that in in "data",  
talpha=2e-4,sbeta=7.4e-4 by default and you can set those parameters  
in "data" as well. tRef(k) and sRef(k) on the other hand, you have to  
set in "data". They are meant to be a reference temperature/salinity  
for the model level k. How you choose them is up to you.
You can also use other eosTypes, where the density is a nonllinear  
function of theta and salt and pressure (JMD95Z, JMD95P, MDJWF),  
based on observations.

Martin
On 23 Feb 2007, at 09:34, Riema Rachmayani wrote:

> hi, all...
>
> when we define our model for nonhydrostatic...we just describe :
> #define ALLOW_NONHYDROSTATIC in code/CPP_OPTIONS.h and activated  
> nonHydrostatic=.TRUE. in input/data and automatically MITgcm will  
> compute the experiment by it self  specially for vertical velocity  
> right??? just want to make it clear and my curiousity about it...
>
> is theta' in rho=rho0(1-alfatheta*theta') ...eq (3.12) in chapter 3  
> is define as Tref in input/data???
> Tref is reference potential temperature (theta0) or fluctuation  
> potential temperature (theta')?? or total potential temperature  
> (theta=theta0+theta') ?? or we use eq 3.13 to find Tref??
>
> thank you,
> regards
> -rima-
>
>
>
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