There are four semi-horizontal layers of “spheres” that
are identified by their vertical temperature distribution in the Earth’s atmosphere.
These four layers are called the troposphere, the stratosphere, the
mesosphere, also called the “mantle” and the thermosphere. Between these
layers are spaces called “pauses”; no temperature change happens when the altitude
changes. Each of these pauses has a specific name. The tropopause occurs between the
troposphere and the stratosphere. The stratopause is found between the mesosphere and
the thermosphere. Together, the stratosphere and the mesosphere are called the middle
atmosphere. This region overlaps with the ionosphere. The ionosphere is define on the
electric charges of the particles found within it.
“Meso”
means middle in Greek. The mesosphere, then, means the middle of the sphere. The
mesosphere is the third layer of the Earth’s atmosphere.
It is found between the stratosphere and the thermosphere and is located about 35 miles
(55 kilometers) to around 54 miles (85 kilometers) from the surface of the Earth. The
mesosphere’s temperatures are dependent on where you are measuring. At its lowest level,
it is the warmest, about 23°F (°C); at its highest, 12°F (0°C). However, depending on
the season and latitude, the uppermost portion can drop to 20°F
(40°C).
Mesospheric temperatures are lower than
temperatures in the troposphere or stratosphere. It is so cold that even Antarctica’s
coldest temperature are higher; it is so cold that water vapor becomes ice clouds,
sometimes visible after sunset.
The air in the mesosphere
is very thin and the atmospheric pressure is low; there is a much lower concentration of
oxygen in the mesosphere than the troposphere; there are only insignificant amounts of
ozone and water vapor. The mesosphere is where many meteors burn
up as they enter the Earth’s atmosphere and collide with other gas
particles within
it.
Source: World
of Earth Science, ©2003 Gale Cengage. All Rights
Reserved
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