Geoscience Reference
In-Depth Information
Table 2.4 Some properties of water
e
∗
de
∗
/
dT
Temperature
c
w
L
e
(
◦
C)
(J kg
−
1
K
−
1
)
(10
6
Jkg
−
1
)
(hPa K
−
1
)
(hPa)
−
20
4354
2.549
1.2540
0.1081
−
10
4271
2.525
2.8627
0.2262
0
4218
2.501
6.1078
0.4438
5
4202
2.489
8.7192
0.6082
10
4192
2.477
12.272
0.8222
15
4186
2.466
17.044
1.098
20
4182
2.453
23.373
1.448
25
4180
2.442
31.671
1.888
30
4178
2.430
42.430
2.435
35
4178
2.418
56.236
3.110
40
4178
2.406
73.777
3.933
c
w
: specific heat;
L
e
: latent heat of vaporization;
e
∗
: saturation vapour
pressure.
Table 2.5 Some properties of ice
e
i
de
i
/
dT
Temperature
c
i
L
fu
L
s
(
◦
C)
(J kg
−
1
K
−
1
)
(10
6
Jkg
−
1
)
(10
6
Jkg
−
1
)
(hPa K
−
1
)
(hPa)
−
20
1959
0.2889
2.838
1.032
0.09905
−
15
—
—
—
1.652
0.1524
−
10
2031
0.3119
2.837
2.597
0.2306
−
5
—
—
—
4.015
0.3432
0
2106
0.3337
2.834
6.107
0.5029
c
i
: specific heat;
L
fu
: latent heat of fusion;
L
s
: latent heat of sublimation;
e
i
:
saturation vapor pressure over ice.
2.1.3
Saturation vapor pressure
The saturation vapor pressure depends only on the temperature, or
e
∗
=
e
∗
(
T
). Some values
are presented in Tables 2.4 and 2.5. These values were obtained from the Goff-Gratch
formulation (see List, 1971), which has been used as the international standard for some
time. For water this formulation is
log
e
∗
=−
7
.
902 98(
T
st
/
T
−
1)
+
5
.
028 08 log(
T
st
/
T
)
−
1
.
3816
×
10
−
7
10
11
.
344(1
−
T
/
T
st
)
−
1
+
8
.
1328
×
10
−
3
10
−
3
.
191 49(
T
st
/
T
−
1)
−
1
+
log
e
st
(2.12)
where log( ) denotes the decimal logarithm,
T
is the temperature in K,
T
st
is the steam-point
temperature 373.16 K, and
e
st
is the saturation vapor pressure at the steam-point temperature,
i.e. 1013.25 hPa; the relationship is also sketched in Figure 2.1. For ice the saturation water
