Θ+ θ, Tp a, Tc t – Vaisala DMT346 User Manual
Page 174

User's Guide _______________________________________________________________________
174 __________________________________________________________________ M210762EN-G
Absolute humidity:
T
P
a
w
⋅
=
68
.
216
(3)
Enthalpy:
x
x
T
h
⋅
+
⋅
+
⋅
−
=
5
.
2
)
00189
.
0
01
.
1
(
)
15
.
273
(
(4)
The water vapor saturation pressure P
ws
is calculated by using two
equations (5 and 6):
∑
=
−
=
Θ
3
o
i
i
i
T
C
T
(5)
where:
T
=
temperature in K
Ci
=
coefficients
C0
=
0.4931358
C1
=
-0.46094296 × 10-2
C2
=
0.13746454 × 10-4
C3
=
-0.12743214 × 10-7
∑
−
=
Θ
+
Θ
=
3
1
4
ln
ln
i
i
i
ws
b
b
P
(6)
where:
bi
=
coefficients
b-1
=
-0.58002206 × 104
b0
=
0.13914993 × 101
b1
=
-0.48640239 × 10-1
b2
=
0.41764768 × 10-4
b3
=
-0.14452093 × 10-7
b4
=
6.5459673
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