;***********************************************************
;  saturation_mxrat.pro calculates saturation mixing ratio
;  with respect to water
;  
;  INPUT
;  temp = temperature in Celcius
;  press = pressure in hPa=mb
;
;  OUTPUT
;  smxrat = saturation mixing ratio in g/kg
;***********************************************************

pro saturation_mxrat_w,temp,press,smxrat

;  Pressure in mb

press_mb=press  ;mb

;  Temperature in celcius

temp_c=temp  ;Celcius

;  Calculate saturation vapor pressure (es)
;  Source: Bolton, D., The computation of equivalent potential temperature, 
;  Monthly Weather Review, 108, 1046-1053, 1980. equation (10)
;  Psat=6.112 * EXP(17.67 * Temp / (Temp+243.5))
;  Temp=Celcius
;  Psat=hPa=mb

es=6.112*exp((17.67*temp_c)/(temp_c+243.5))  ;mb

;  Calculate mixing ratio
;  mxrat=(0.622*e)/(p-e) where e is vapor pressure
;                              p is pressure
;                          mxrat is mixing ratio

smxrat=(0.622*es)/(press_mb-es)  ;kg water vapor / kg dry air

;  Convert mixing ratio from kg/kg to g/kg

smxrat=smxrat*1000.0

return
end