Geoscience Reference
In-Depth Information
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
123
4
5
6
7
8910
11
12
Time (month)
Figure 2.3
Climatology of relative sunshine duration for two European stations: Oslo
(top; 59°56ʹN) and Valencia (bottom; 39°29ʹN) for the period 1971-2000. Symbols
indicate the mean; ranges indicate 25% and 75% percentiles. (Data from Klein Tank
et al.,
2002
)
Figure 2.4
Relationship between shortwave radiation at top of atmosphere and
direct and diffuse radiation at Earth's Surface for cloudless sky (left) and cloudy sky
(right).
Extinction: General
The total effect of the atmosphere on solar radiation will depend on the length of the
path of the radiation through the atmosphere. Or more precisely, it will depend on the
number of molecules and particles encountered by the radiation. Therefore, the path
length is expressed as an optical mass (
m
a
): the total mass (per unit area) along the
path of the radiation:
0
∫
ρ
mds
a
=
(2.5)
∞
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