remove alpha and asymmetry

Author: williamhobbs

pvlib/iotools/psm4.py

@@ -67,8 +67,6 @@
     'albedo': 'surface_albedo',
     'precipitable_water': 'total_precipitable_water',
     'aod': 'aod',
-    'alpha': 'alpha',
-    'asymmetry': 'asymmetry',
 }
 
 
@@ -776,7 +774,6 @@ def parse_nsrdb_psm4(fbuf, map_variables=True):
 
     if map_variables:
         data = data.rename(columns=VARIABLE_MAP)
-        data = data.drop(columns=[col for col in data if col not in VARIABLE_MAP])
         metadata['latitude'] = metadata.pop('Latitude')
         metadata['longitude'] = metadata.pop('Longitude')
         metadata['altitude'] = metadata.pop('Elevation')