CDO

Hey,

I use the CCLM model with a rotated coordinate system with the following setup:

cdo -selname,U_10M,V10M originalOutput.nc uv.nc
cdo -setgrid,grid.txt uv_grid.nc
cdo -rotuvb,U_10M,V10M geouv.nc

This worked fine until it was used with another cdo version (and computer) by a colleague of mine.
Tracking down the problem I made an artifical wind field (U=10m/s, V=0m/s)
on my rotated grid (northpol @ lon=0,lat=-77.5) and my domain, which covers a part of Antarctica INCLUDING the South Pole (in the bottem right corner).

In the attached "rotuvb.PNG" the two green fields show the original artifical wind in the rotated system.
The U wind is the same for all rotations. But the V wind has different values. (other 4 plots)
(In case anyone is wondering about the white line... its the coast line of Africa, produced by ncview by not getting the rotation and using the rotated lat/lon as actual geo lat/lon)

I attached the files.
The command I used was:
cdo -rotuvb,U_10M,V_10M -setgrid,grid.txt arti_UV_10M.nc arti_geoUV_10M.nc

A colleague of mine also tried different cdo versions (same and different computers). So we would conclude:
up to 1.6.8 rotuvb works with this setup
from 1.7.0 it doesn´t work anymore in this setup

Did the conventions on the grid description (grid.txt) change?

with kind regards
Rolf