Atmosphere layers

15.1

Thermosphere• Extends from 80km out• Air is thinnest in this layer and much less dense• Temp rises the higher you go (molecules moving

fast)• Has 2 layers:– Ionosphere – 80-400km-Contains charged particles

that reflect radio waves back to Earth and cause light displays like Aurora Borealis at high latitudes

– Exosphere – outer portion and extends from 400+km getting thinner as it extends out to vacuum of space

Mesosphere

• Extends from 50-80 km above Earth (third layer going up)

• Protects Earth’s surface from being hit by most meteoroids (they burn up in this layer)

• Air is less dense than in the stratosphere• As you go up in the mesosphere the

temperature decreases• Coldest layer

Stratosphere• Extends from 12-50 km above the Earth (2nd

layer)• Contains ozone (O₃) layer which filters out

harmful ultraviolet rays from Sun• Ozone absorbs energy and converts it to heat• As you get higher in the ozone layer the

temperature rises• In Stratosphere air is less dense than in the

Troposphere

Troposphere

• The layer of the atmosphere in which clouds and weather occur.

• Thinnest layer but contains most of the mass because gas molecules are denser (closer together) than in other layers.

• 0-12 km above Earth’s surface – Lowest layer• Temperature goes down the higher you get in

the troposphere