CDO

Dear All,

I'm not sure if this is a bug or a mistake in my installation of cdo. I am using cdo version 1.7.2

I have files in pressure coordinates. For example, vwind.2000.nc from this site: https://www.esrl.noaa.gov/psd/cgi-bin/db_search/DBListFiles.pl?did=32&tid=56952&vid=667
The file is daily interval with 17 pressure levels. When I ncdump -h the original file, the level attributes has the following description:

float level(level) ;
level:units = "millibar" ;
level:actual_range = 1000.f, 10.f ;
level:long_name = "Level" ;
level:positive = "down" ;
level:GRIB_id = 100s ;
level:GRIB_name = "hPa" ;
level:axis = "Z" ;

When I try a simple operation using cdo(in this case, cdo ymonmean ifile ofile), the attributes for the level changed:

float level(level) ;
level:standard_name = "air_pressure" ;
level:long_name = "Level" ;
level:units = "millibar" ;
level:positive = "up" ;
level:axis = "Z" ;

The level:positive="down" changed to "up". Although, I can change this attribute using nco, I do not know if this is a bug or a mistake in the installation process.
Has anyone experienced the same problems before? I am attaching here the output of the ncdump -h.