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.