ESS11
Prof. Jin-Yi Yu
The Scale Height of the
Atmosphere
q One way to measure how soon the air runs out
in the atmosphere is to calculate the height of an
atmosphere of constant density that
exerts the same pressure as our atmosphere at Earth’s
surface.
qThis height, which is
about 10 km, is called the scale height of the atmosphere.
qOver this vertical
distance, air pressure and density decrease by 37% of its surface values.
qIf pressure at the
surface is 1 atmosphere, then it is 0.37 atmospheres at a height
of 10 km, 0.14 (0.37x0.37) at 20 km, 0.05 (0.37x0.37x0.37)
at 30 km, and so on.
qMost (80%) of the mass
of the atmosphere is confined in the first 10 km from the
surface.