[Wrf-users] Dimension problems between 3DVAR and WRF

[Thorsten Beisiegel]

Dear Users,

while comparing the output from 3DVAR with output from WRF we notice a difference in dimension between the wrf_3dvar_output file and the wrfout_d0* file for the same domain. The result is an error in grads using variables from both files in the same ecuation. 

The horizontal extensions of the 3DVAR grid seems to be reduced by almost one grid point distance, anyway it has the same number of points and grid point distance for the cartesian grid in each direction as the wrfout file.

As grid spacing an number of grid points are the same for both files, the problem seems to represent a difference in the proyection. But both files where generated with the same proyection parameters, 

 MAP_PROJ_NAME =  'mercator'
 MOAD_KNOWN_LAT =   10.60
 MOAD_KNOWN_LON =  -73.15
 MOAD_STAND_LATS =  10.60, 0
 MOAD_STAND_LONS = -74.15

Also the grads input files for both cases were written with the same wrf2grads executable.
Anyway with the "levels" option in the .ctl file  the number of points is the same in x and y but the values for latitude and longitude are not, they differ for 3DVAR output and WRF output. 

I wonder if the fact that 3dvar only uses initial conditions while WRF includes the boundary data could be a reason.

Many thanks for any hint

Thorsten