IMPORTANT:
Each file should have the same module name; i.e. the source
file names will differ but the module name inside the file
must be the same across all modules in this directory.

All the subroutines must also have the same names and
calling sequence. They must return appropriate values 
for each observation type that is required.  
If errors for a new observation type is added, it should
be added to all the files in this directory.

public :: metar_pres_error,              &
              metar_rel_hum_error,           &
              metar_temp_error,              &
              metar_wind_error