Campbell Scientific EC150 CO2 and H2O Open-Path Gas Analyzer and EC100 Electronics with Optional CSAT3A 3D Sonic Anemometer - Manual (Page 71)

Appendix D. Useful Equations
Vapor Pressure from Molar Mixing Ratio and Water Vapor Density
v
v
X
P X
e
+
=
1000
(D-12)
( )
v
v
M
T R
e
15 . 273 +
=
ρ
(D-13)
Equations (D-1) and (D-2) were derived from:
Leuning, R.: 2005, “Measurements of Trace Gas Fluxes in the
Atmosphere Using Eddy Covariance: WPL Corrections Revisited”,
Handbook of Micrometeorology, 29, 119-132.
Equations (D-3), (D-4), (D-5), (D-7), (D-9), and (D-13) were derived from:
Bolton, D.: 1980, “The Computation of Equivalent Potential
Temperature”, Monthly Weather Review, 108, 1046-1053.
Equations (D-6), (D-8), (D-10) and (D-11) were derived from:
Buck, A. L.: 1981; “New Equations for Computing Vapor Pressure and
Enhancement Factor”, Journal of Applied Meteorology, 20, 1528-1532.
D-3