Visualizing Environmental Science

Ozone layer

Mesosphere

Stratosphere

Troposphere

Thermosphere

Extends to 480 km (300 mi)

Gases in extremely thin air absorb x-rays and

short-wave radiation, raising the temperature

to 1000°C (1800°F) or more. The thermosphere

is important in long-distance communication

because it reflects outgoing radio waves back

to Earth without the use of satellites. Auroras

occur here.

Extends to 80 km (50 mi)

Directly above the stratosphere, temperatures

drop to the lowest in the atmosphere—as low

as –138°C (–216°F). Meteors often burn up

from friction with air molecules in the

mesosphere.

Extends to 50 km (30 mi)

Steady wind occurs but no turbulence;

commercial jets fly here. Contains a layer of

ozone that absorbs much of the sun’s damaging

ultraviolet (UV) radiation. Temperature increases

with increasing altitude because absorption of

UV radiation by ozone layer heats the air.

Average thickness: 12 km (7.5 mi)

16 km (10 mi) thick at equator

8 km (5 mi) thick at poles

Layer of atmosphere closest to Earth’s surface.

Temperature decreases with increasing

altitude. Weather, including turbulent wind,

storms, and most clouds, occurs here.

Antony Spencer/E+/Getty Images

Kenneth Garrett/NG Image Collection

b. A Thunderstorm in New Mexico. During

a lightning flash, a negative charge moves

from the bottom of the cloud to the ground,

followed by an upward-moving charge

along the same channel. The expansion

of air around the lightning strike produces

sound waves, or thunder.

a. Layers of Atmosphere.

c. An Aurora in the Northern

Hemisphere. Electrically charged

particles from the sun collide with the gas

molecules in the thermosphere, releasing

energy visible as light of different colors.

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The Atmosphere 193