Layers of Atmosphere
• The four main layers of the atmosphere are classified according to changes in temperature.
• The layers are:
– Troposphere
– Stratosphere
– Mesosphere
– Thermosphere
The Troposphere
• It extends from the
Earth’s surface to more than 16 km and less than 9 km above the poles.
• Where weather occurs.
• Contains almost all
of the atmospheric mass.
• On average, air cools
6.5° C for every km increase in altitude.
The Stratosphere
• 12 km
- 50 km
•
Commercial aircraft fly in the lower portions.
• Contains the ozone layer.
• Upper stratosphere
is warmer than the lower stratosphere (-60° C).
• The
ozone layer absorbs energy from the sun, converts it to heat, warming the air.
Mesosphere
• Middle layer (meso = middle)
• 50km
to 80 km
•
A drop in temperature above the stratosphere marks the beginning of the mesosphere.
•
Temperatures approach -90° C
• Meteoroids burn up here.
Thermosphere
• 80 km
– into space
•
No definite outer limit.
• The
air becomes very thin.
• Thermo = heat
• The temperature is up to 1800° C! However, you would not feel warm.
• It’s divided into 2 layers.
• The ionosphere
• 80 km to 550 km
• Filled with
electrically charged gas particles.
• Radio
waves bounce off of the ionosphere
• Particles
from the sun enter the ionosphere and cause the ions to glow. (Northern Lights)
• The Exosphere
• Exo = outer
• Outer most layer of the atmosphere
• Location
of most man-made satellites.