Figure 7. The global radiation balance at the top of
the atmosphere and at the earth's surface. Part of the total incoming solar
energy 340 W m-2 is absorbed by clouds and atmospheric gases and part is
reflected by clouds, atmospheric gases and the ground (land and water surfaces).
Approximately half (170 W m-2) is absorbed by the ground. Some of this
energy is re-radiated upward and some transferred to the atmosphere as
‘sensible’ and ‘latent’ heat by turbulence and convection. The atmosphere
radiates infrared radiation in all directions. When balance is achieved
in the atmosphere, the total (short wave and long wave) upward radiation
from the top of the atmosphere equals the 340 W m-2 received from the sun.
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