I have tried to re-build everything using system libraries from yum and the problem is still here.
I have used meteoadriatic unipost.exe and the problem is still here.
As meteoadriatic said, now I know my unipost.exe is good and the issue must be elsewhere in my system.
Now what direction I could go ???
At this moment I do not know which direction to take...
I'm thinking of abandoning Unified Post Processor and try to pull out the cloud cover directly from wrf_out files using a tool like NCL
, that I have already successfully build on my system.
In particular ARW wrf_out netcdf files already contain by default the field CLDFRA, a 3D field representing the cloud fraction (values between 0 and 1) on the model levels.
Perhaps one can use this to calculate the low, middle and high level cloud fractions and plot these to a map...
Or maybe exists a way to instruct unipost to write a CLDFRA field into the GRIB file onto z-levels ?
if it were available a similar field in the GRIB file, then it should not be difficult write down a short GrADS script to calculate the total cloud cover between two arbitrary pressure levels or better between two arbitrary above sea height levels.
Note: my unipost.exe is 64.4 MB, meteoadriatic unipost.exe is 78.9 MB. Why this difference?