CDO

Hi Rob,
Yes, this operator was designed for ECHAM and ECMWF ERA GRIB files. Therefore only the WMO standard GRIB table number 2 and ECMWF local GRIB table number 128 are supported. The input file should contain the surface pressure. In netCDF files the surface pressure needs to have the name "aps" or "sp". So you have to rename the variable PS to "sp":

cdo mp2pl,....  -chname,PS,sp ifile ofile

Best regards,
Uwe

Rob Nicholas wrote:

Does anyone have any experience using the 'ml2pl' operator to convert the hybrid levels used by NCAR CAM3 to pressure levels? I assume this operator was designed with ECHAM5 conventions in mind, but CAM/CCSM appears to use different variable names and/or code numbers, so the operator fails in that case. A sample file, containing zonal winds (U) on 26 hybrid levels and (I believe) all of the necessary conversion data, is attached.

Uwe, could you say more about what this operator expects?

Thanks,
Rob

HI,
I have maybe a similar problem, I would like to use ml2pl to convert output on modellevels from a NCAR model to pressure levels. I changed the names of the variable for the surface pressure to 'aps' and then for another try to 'sp' as suggested but still it doesn't work. I get the error message: " cdo ml2pl (Abort): Grids have different size!"
so my question is, does anybody know what this means? Is the number of lat or lon -values important for this conversion?
thanks a lot,
Viktoria

Hi Viktoria,

The error message means that some fields in your file have different size of the horizontal grid. The limitation for the function ml2pl is that all fields must be on the same horizontal grid. You can check the contents of the file with sinfov.

Best regards,
Uwe

Hi Uwe,
sorry I just recognized your answer.
Thanks a lot I think now I found the Problem. Seems like I had some variables in my files only containing one number and not a field!
regards,
Viktoria

Hi Uwe,

Any idea what the surface geopotential variable should be renamed to, if I am converting temperature?

Thanks
Anamitra

geopotential should have the name 'geosp' (surface) or 'geopotential_full'