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The layer above the troposphere is called the stratosphere
which is 32 kilometers thick (20 miles). This is a region of horizontal
air motion and where you find the jet stream. The jet stream is high
winds blowing at about 300 km/hr. The jet stream helps airplanes go
faster, when the plane goes in the same direction as the wind.
This stratosphere is usually devoid of clouds and
has temperatures ranging from -50 to 60 C. The temperature increases
gradually, due to the absorption of ultraviolet radiation.
The upper part of the stratosphere contains a higher percentage of ozone.
This layer of ozone is a form of oxygen that protects the surface of the
Earth from the Sun's ultraviolet rays. The uppermost layer of the
stratosphere is called the stratopause.
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