RAF Bulletin No. 9

APPENDIX C

Enhancement Factors (as recommended by Buck, 1981)

A.  fw =  enhancement factor for calculation of the water vapor
          pressure of moist air with respect to a plane water
          surface:
               fw = 1.0007+(3.46x10^-6 P)
where:
     P = pressure, mbar

B.  fi =  enhancement factor for calculation of the water vapor
          pressure of moist air with respect to a plane ice
          surface:
               fi = 1.0003+(4.18x10^-6 P)
where:
     P = pressure, mbar

Thus, water vapor pressure for moist air is calculated as
follows:
          ewc = fw ew
          eic = fi ei
where:
     ewc, eic  = water vapor pressure for "moist" air
     fw,  fi  = enhancement factors
     ew,  ei  = water vapor pressure as calculated by Goff-Gratch