Winds in rotated grid
Added by Alejandro Martínez over 13 years ago
Hello:
I need to obtain some fields in a rotated grid. To rotate scalar fields I'm using:
cdo rempacon2,targetgrid -setgrid,sourcegrid ifile ofile
I want to know what is the procedure with vector fields, like wind (u,v,w). Thanks in advance for any help.
Alejo
Replies (4)
RE: Winds in rotated grid - Added by Uwe Schulzweida over 13 years ago
Hello Alejo,
CDO can only interpolate scalar fields. The general procedure for vector fields on a rotated grid is:- Transformation of u and v from the grid cell edges to grid cell center
- Rotate the coordinates from the rotated spherical system to a geographical system
The second point can be done with the CDO function rotuvb. This function was implemented for our regional model REMO and will possibly not work on your data.
Best regards,
Uwe
RE: Winds in rotated grid - Added by Alejandro Martínez over 13 years ago
Hello Uwe,
Thank you very much for your answer. I used the rotuvb function but when I ask for the grid information (using griddes) of the new file I obtain the same information of the original rotated field. How can I know that the rotation has been actually performed?
Thank you in advance for any information.
Best regards,
Alejo
RE: Winds in rotated grid - Added by Uwe Schulzweida over 13 years ago
Hello Alejo,
The grid description does not change with the operator rotuvb. Only the values of the u and v field change. You can see the changes with
e.g. info.
Best regards,
Uwe
RE: Winds in rotated grid - Added by Alejandro Martínez over 13 years ago
Hello Uwe,
I have another question. I can rotate the wind field as you told me, but the new field will be located in the "old" grid (being the old grid the rotated one and the new grid the geographic one). To get the new field in the new grid can I use an operator of interpolation (e.g. remapcon) over each component of the wind field?
Thank you very much for your attention and patience!
Best regards,
Alejo