fix some cf issues

modules/aeolus/aeolus_amv.py

@@ -2070,6 +2070,7 @@ def create_bestfit_file(filename, match_dct, raob_dct, gfs_at_raob_dct, bf_dct,
 
     time = rootgrp.createVariable('time', 'f4', ['time'])
     time.units = 'seconds since 1970-01-1 00:00:00'
+    time.calendar = 'standard'
     #amv_file_names = rootgrp.createVariable('amv_file_names', str, ['num_amv_files'])
 
     # ---- Profile variables ---------------