5/20/14

Composition78% Nitrogen (N2)

Released when living things decay and volcanoes erupt

21% Oxygen (O2)Produced by plants and some

protists during photosynthesis1% Various Atmospheric

GasesWater vapor Carbon Dioxide

Solid particles such as dirt, dust, and ash are carried in air

Atmospheric PressureAtmosphere is held in

place by Earth’s gravityGravity pulls on gas

molecules

Air pressureStronger near surfaceWeaker the further away

Altitude Air Pressure

Atmospheric TemperatureAir temperature

changes as you increase altitudeSections of warmer

and colder temperatures

Temperature changes based on how solar energy is absorbedType of gases affect

solar absorption

Layers of AtmosphereDivided into four

layers based on temperatureTroposphereStratosphereMesosphereThermosphere

“-sphere” each layer surrounds the Earth like a hollow ball

TroposphereLowest layer of the

atmosphereWe live here

Densest of the four layers90% of

atmosphere’s total mass

Layer in which weather occurs

Extends to 6-7 miles (~33,000 ft) above Earth’s surface

StratosphereLocated above the

troposphereAir is very thin and

contains little moistureFew clouds exist here

Contains the Ozone Layer (O3)Protects from UV rays

Ranges from 7-31 miles above the Earth’s surface

MesosphereLocated above the

stratosphereColdest layer of the

atmosphereAs low as -90oC (-

130oF)Difficult to study layer

Weather balloons and aircraft cannot reach layer

Extends from 31-53 miles above Earth’s surface

Mesospheric Clouds

ThermosphereUppermost atmospheric

layer Warmest layer of the

atmosphereAs high as 1,700oC (3,100oF)Influenced by solar radiation

Contains the Ionosphere and Aurora borealisElectrically charged particles

Extends from 56-311 (or 621) miles above Earth’s surface

International Space Station