The Atmosphere and Climate Modeling - Introduction to Carbon Capture and Sequestration - page 53

100

Thermosphere

80

temperature

60

Mesosphere

40

Stratosphere

20

density

pressure

Troposphere
density

0

0 0.5 1.0 1.5

0 550 100 150 pressure

temperature 0 200 250 300

Figure 2.3.1 Properties of the atmosphere
The pressure (in kPa), density (in kg/dm 3 ), and temperature (in K) as a function of the
altitude (in km).

(UV) and visible light part of the spectrum, while the earth emits in the
infrared region. If we look at the sun, we of course see the difference
between a cloudy and a clear day; in addition, the probability of sunburn
is much lower when the sky is overcast. The clouds refl ect most of the
radiation from the sun, but without clouds the atmosphere is transparent
to UV and visible light. This is very different for the infrared radiation emit-
ted by the earth; at these wavelengths the atmosphere is absorbing.
Thus the greenhouse effect is the differential absorption in the atmos-
phere between solar radiation and the earth's blackbody emission. In
Figure 2.3.2 the emission spectra of the sun and earth are compared
with the absorption spectrum of the atmosphere.
We can also investigate which gasses contribute most to the green-
house effect ( Table 2.3.1 ). These gasses are, in decreasing order of their
contribution: water, carbon dioxide, methane, and ozone. The concentra-
tions of these and other gasses in the atmosphere are shown in