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Meteorology
3.2.1.1 Temperature in the Troposphere
The figure shows the
temperature distribution
with altitude.
As seen, the average
temperature at MSL
(Mean Sea Level) is about
15°C.
The temperature drops
with increasing altitude in
the lower part of the
atmosphere, the troposphere.
The figure here shows the curvature of the Earth.
The atmosphere follows the Earth's rotation.
The red arc represents the tropopause.
As can be observed, the height of the tropopause is
greater at the equator than at the poles.
This is because warm air at the equator expands more
vertically than cold air at the poles.
This also means that the tropopause is higher on a hot day than on a cold day.
At the poles, the height to the tropopause is about 30,000 feet. At the equator,
it's about twice that, 60,000 feet.
The Earth's circumference around the equator is about 40,075 km, while at the
poles, it's slightly smaller, around 40,008 km.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 215
