[MITgcm-support] Velocity cubed sphere + pickup seaice

[Elja Huibregtse]

Hi Martin,

The angles are indeed independent of the radius. But I'm still confused about how to change the parameters dxc, dyc, dxg etc. 

The default of the cube-sphere integration (with sea ice on the cs32 grid) is:  usingCurvilinearGrid=.TRUE.
Trying usingSphericalPolarGrid=.TRUE. to make sure that dxg etc are adapted to the correct configuration, doesn't work; I get a segmentation fault.  

I use the cubed sphere configuration (cs32), which means that the grid_cs32.face[n].bin files, with n=1..6, are read and used. Are these files (containing all cubed-sphere grid lengths, areas and grid-point positions) 'fixed' or based on the current configuration (radius)? In the model, I often use recip_dxc etc, which are (as far as I understand) dependent on these grid_cs32.face[n].bin files. Because recip_dxc etc, haven't been adapted, I use the wrong values.

I guess that the grid_cs32.face[n].bin files change if usingSphericalPolarGrid=.TRUE., but this doesn't work.
Thus, do I have to adapt the grid_cs32.face[n].bin files myself? Or is there another way to automatically change the parameters?

Thanks for your help,

Elja 



-----Oorspronkelijk bericht-----
Van: mitgcm-support-bounces at mitgcm.org namens Martin Losch
Verzonden: wo 6/4/2008 12:17
Aan: mitgcm-support at mitgcm.org
Onderwerp: Re: [MITgcm-support] Velocity cubed sphere + pickup seaice
 
Elja,
you don't need to change set_defaults.F, you can set most of the  
relevant parameters (such as rSphere, rotationPeriod or omega, etc in  
"data"; have a look at ini_parms.F to see which parameters are  
available in namelists.

rac=dxg*dyg in meters^2 (etc.), dxg etc are computed based on the  
value of rSphere (if "usingSphericalPolarGrid=.true."). the radius is  
only hard-coded in cubeCalcAngle.m, but does that matter? The angles  
are absolutely independent of the radius, right?

Martin

On 4 Jun 2008, at 11:06, Elja Huibregtse wrote:

> Thanks, Martin and Dimitris, for your useful replies.
>
> My study object is a moon of Jupiter, thus the radius and other  
> parameters differ from those used for the Earth. I changed all  
> these parameters in set_defaults.f. Trying to calculate the values  
> of angleCosC and angleSinC, I found out that the radius stored in  
> RAC (calculated from: r_earth=sqrt(sum(sum(RAC))./(4.*pi)) in  
> cubeCalcAngle.m, line 23), is still the radius of the Earth.
>
> Now, I think that all the 'coordinate' files, like RAC, RAS, RAZ  
> etc. still contain the configuration of the Earth, which will, of  
> course, influence my results. Is it possible to adapt those files  
> to the correct configuration?
>
> Thanks!
> Elja
>
>
> -----Oorspronkelijk bericht-----
> Van: mitgcm-support-bounces at mitgcm.org namens Martin Losch
> Verzonden: wo 6/4/2008 8:54
> Aan: mitgcm-support at mitgcm.org
> Onderwerp: Re: [MITgcm-support] Velocity cubed sphere + pickup seaice
>
> Hi Elja,
>
> in addition, the orientation of u and v-velocity is along grid
> coordinates, which will give you funny results, if you try to plot
> them on some sort of map-projection. After interpolating, you need to
> rotate the velocities according to the values of angleCosC and
> angleSinC. Unfortunately, these fields are often not set, because the
> model does not need them for hydrostatic integrations (so that they
> are 1 and 0). There is a matlab script to compute the angles in
> <utils/matlab/cs_grid/cubeCalcAngle.m>
>
> I am also attaching a matlab function that does the interpolation and
> takes care of the edges (for me, so I am not sure that this will work
> for you or anyone else, too).
>
> Martin
>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
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