Earth is surrounded by a mixture of gases

known as the Atmosphere

The Atmosphere

Composition of the AtmosphereNitrogen – 78%Oxygen – 21%Other – 1% (Argon, CO2, Water Vapor, others)

Air PressureEarth’s atmosphere is pulled towards Earth’s surface by gravity. Thus, the atmosphere is denser at the surface and less dense at higher altitudes.

Layers of the AtmosphereTroposphere- closestto the Earth’s surface.Where our weatheroccurs.

Layers of the AtmosphereStratosphere – 2nd

layer. Contains the Ozone layer.

Layers of the AtmosphereMesosphere- 3rd

layer, helps in protecting us frommeteors.

Layers of the AtmosphereThermosphere – Farthest from the Earth’s surface. Warmest layer, Interactions withsolar radiation causesthe aurora borealis.

Energy in the Atmosphere

Energy in the AtmosphereAbout 50 % of incoming solar energy is absorbed by Earth’s surfaces.

About 50% is reflected back into space in the form of low level infrared radiation.

Energy Transfer in the Atmosphere

Radiation – the transfer by waves

Convection – the transfer by air movement

Conduction- the transfer by the touching of one object to another

Greenhouse EffectThe process by which gases trap heat near

the Earth’s surface.