Geoscience Reference
In-Depth Information
Main atmospheric absorption bands
H
2
O
H
2
O
H
2
O
O
3
O
2
CO
2
O
3
CO
2
3500
Black-body radiation at 6000°K (1.6k Wm
-2
)
Incoming solar
Extraterrestrial solar
radiation
(1370W m
-2
)
2000
Outgoing terrestrial
1000
500
0
5
10
15
20
25
μm
Direct beam (normal incidence) solar radiation
at the earth's surface (907 Wm
-2
)
200
Black-body radiation 300°K
(468W m
-2
)
100
50
Estimated infrared
emission to space
from the earth's
surface (70W m
-2
)
10 μm
12 μm
20
10
5
Black-body
radiation
263°K
(270W m
-2
)
2
1
01
02
05
10
20
50
10
20
50
10
Wavelength (
μm)
Ultraviolet
Visible
Infrared
Figure 3.1
Spectral distribution of solar and terrestrial radiation, plotted logarithmically, together with the
main atmospheric absorption bands due to trace gases (top). The cross-hatched areas in the infrared
spectrum indicate the 'atmospheric windows' where radiation escapes to space. The black-body radiation
at 6000K is that proportion of the flux which would be incident on the top of the atmosphere. The inset
shows the same curves for incoming and outgoing radiation with the wavelength plotted arithmetically on
an arbitrary vertical scale.
Source: Mostly after Sellers (1965). Courtesy of University of Chicago Press.
