[MITgcm-support] Initial Wind on Cubed Sphere

[Jean-Michel Campin]

Hi Chris,

Depending on the wind field, you may try one of the 2 methods:
1) general method (similar to what is done within matlab script
 utils/matlab/cs_grid/uvLatLon2cube.m): your can define your wind field
 on a lat-lon grid and then use uvLatLon2cube.m to interpolate + rotate
 to CS-grid direction + put the uVel,vVel on to C-grid location;
Or, you can skip the interpolation stage and define your wind field
 on the CS-grid, at the grid-cell center location and then just do
 the rotation + the move to C-grid location.
2) specific method for non-divergent wind-field (this is a special case
 which is not uncommon): From the analytical expression of the wind,
 you can derive an analytical expression of the horizontal stream-function.
 Then you evaluate the stream-function on the CS-grid at the grid-cell corner
  (position XG,YG) and from there you can compute directly the wind
 at the C-grid location (this ensure that uVel,vVel field is non divergent).
 There are few matlab scripts that uses this 2nd method (e.g., in
 MITgcm_contrib/dyncore_ASP/mat_scripts ) and also some fortran code
 (e.g., verification/advect_cs/code/ini_vel.F or 
   verification/code/solid-body.cs-32x32x1/code/ini_vel.F).

Cheers,
Jean-Michel

On Tue, May 01, 2012 at 02:34:45PM +0100, Chris Watkins wrote:
> I am trying to set up an initial wind field using the file ini_vel.f on a
> cubed sphere. I know analytically what the meridional and zonal winds
> should be on a latitude-longitude grid. Can anyone help me understand what
> adjustments I need to make to these values to make them into the uVel and
> vVel variables.
> 
> I originally set uVel to the zonal wind and vVel to the meridional wind but
> the output for U & V  for timestep 0 does not match.
> 
> -- 
> Chris Watkins

> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support