Use first valid time as base_time

main.py

@@ -34,8 +34,8 @@ def save_quality(frame, qc_path):
     for variable_qc in frame.filter(like='qc_'):
         if variable_qc not in ['qc_notes','qc_percent']:
             ncdf.createVariable(variable_qc, 'f4', ('time',))[:] = frame[variable_qc].values
-    base_time[:] = frame.datetime[0].to_datetime64()
-    time_offset[:] = (frame.datetime - frame.datetime[0]).values
+    base_time[:] = frame.datetime.dropna().iloc[0].to_datetime64()
+    time_offset[:] = (frame.datetime - frame.datetime.dropna().iloc[0]).values
     qc_percent[:] = frame['qc_percent'].values
     qc_notes[:] = frame['qc_notes'].fillna('').values
     ncdf.close()