Wrong calendar sometimes used in nudging.

[menzel-gfdl]

Describe the bug
The calendar variable should be changed to "calendar" on this line:

GFDL_atmos_cubed_sphere/GFDL_tools/read_climate_nudge_data.F90

Line 265 in 03e4164

if( variable_att_exists(fileobj, time_axis, calendar) ) then

This is causing the calendar attribute to not be read in the file, possibly leading to the wrong calendar being used in the run.

To Reproduce
Try any nudging run where the calendar attribute on the time axis is not gregorian.

Expected behavior
The correct calendar type should be used.

System Environment
This will probably happen on all systems.

Additional context

[menzel-gfdl]

@bensonr @laurenchilutti Do you agree? Should I make a pull request?

[laurenchilutti]

@menzel-gfdl I agree with what you are saying. Good catch! I am fine with you putting in a pull request for this.

[laurenchilutti]

Fixed by PR #157