Campbell Scientific EC150 CO2 and H2O Open-Path Gas Analyzer and EC100 Electronics with Optional CSAT3A 3D Sonic Anemometer - Manual (Page 70)

Appendix D. Useful Equations
( )
15 . 273
1000
+






+
−
=
T R
M
X
P X
P
d
v
v
d
ρ
(D-4)
( ) 





+
−






+
=
v
v d
d X
X
T R
PM
1000
1
15 . 273
ρ (D-5)
Dew Point from Molar Mixing Ratio
tmp d
tmp d
d T
T
T
_
_
502 . 17
97 . 240
−
= (D-6)
( ) 





+ ⋅
=
v
v
tmp d X f
P X
ln T
1000 61121 . 0 _
(D-7)
( ) ( )
2 9 5 10 9 . 5 10 2 . 3 00072 . 1 PT P f − − Ч + Ч + = (D-8)
Water Vapor Molar Mixing Ratio from Dew Point
1000
e P
e
X
v −
= (D-9)






+
⋅ ⋅ =
d
d
T
T
EXP f e
97 . 240
502 . 17
61121 . 0
(D-10)
Water Vapor Mass Density from Dew Point
( )( )
( ) 





+ +
=
d
d
v T
T
EXP
T R
f
97 . 240
502 . 17
15 . 273
61121 . 0 018 . 0
ρ
(D-11)
D-2