Relative humidity averaging from specific humidity

From @signehl #188 :

As far as I can see the resampling to hourly averages is the same for all variables, except for wind direction. Have I missed somewhere where rh is treated differently or are rh values also simple hourly averages? I am asking because I think for the average to make physical sense they need to be converted to specific humidity (and perhaps then back to rh?), but I am not sure?

Special averaging needed according to Campbell: https://www.campbellsci.com/blog/averaging-relative-humidity

Relative humidity exception should be raised here in the L3 resampling step:

pypromice/src/pypromice/process/aws.py

Lines 736 to 744 in 02b32a9

    
           df_d = ds_h.to_dataframe().resample(t).mean() 
        
           # recalculating wind direction from averaged directional wind speeds 
        
           for var in ['wdir_u','wdir_l','wdir_i']: 
        
               if var in df_d.columns: 
        
                   if ('wspd_x_'+var.split('_')[1] in df_d.columns) & ('wspd_x_'+var.split('_')[1] in df_d.columns): 
        
                       df_d[var] = _calcWindDir(df_d['wspd_x_'+var.split('_')[1]], 
        
                                          df_d['wspd_y_'+var.split('_')[1]]) 
        
                   else: 
        
                       logger.info(var,'in dataframe but not','wspd_x_'+var.split('_')[1],'wspd_x_'+var.split('_')[1])

	df_d = ds_h.to_dataframe().resample(t).mean()
	# recalculating wind direction from averaged directional wind speeds
	for var in ['wdir_u','wdir_l','wdir_i']:
	if var in df_d.columns:
	if ('wspd_x_'+var.split('_')[1] in df_d.columns) & ('wspd_x_'+var.split('_')[1] in df_d.columns):
	df_d[var] = _calcWindDir(df_d['wspd_x_'+var.split('_')[1]],
	df_d['wspd_y_'+var.split('_')[1]])
	else:
	logger.info(var,'in dataframe but not','wspd_x_'+var.split('_')[1],'wspd_x_'+var.split('_')[1])