Unit error false positive

[aaschwanden]

The compliance checker flags exponents in units like m^2.
This spelling is CF conform, see https://cfconventions.org/Data/cf-conventions/cf-conventions-1.11/cf-conventions.html#units because it is UDUNITS conform.

"The value of the units attribute is a string that can be recognized by the UDUNITS package [UDUNITS], with the exceptions that are given in Section 3.1.1, "Dimensionless units" and Section 3.1.3, "Scale factors and offsets"."

For PISM we use m^2 not m2 because pint_xarray does not recognize m2, see pism/pism#544

 
NAMING Tests 
 - Filename year range 1985-2014 matches time axis: OK
** Tested Variable: acabf
 
NUMERICAL Tests 
 - ERROR: The unit of the variable is kg m^-2 s^-1 and should be kg m-2 s-1```