Earth’s Atmosphere. Nebraska Supercell Storm Cloud - Oklahoma.

Earth’s Atmosphere

Nebraska Supercell

Storm Cloud - Oklahoma

Mt Rainier, Washington

Interesting Facts…

• The average temp on Earth is 63F (17C)• Ice Age global temp is 54F (12C)

• Due to the Earth’s rotation, our planet bulges out at the equator

• Without plate tectonics, we would overheat– Subduction recycles carbon

Why is our atmosphere important?

• Importance– Makes life on Earth possible– Protective barrier around Earth– Maintains balance between absorbed and heat

lost– Protects life from UV rays

– If we didn’t have one…– We would be burned by the intense heat during

the day and frozen by the low temps at night

I

What is our atmosphere made of?

• Consists of FIVE layers from the surface to space

• Held in place by the Earth’s gravity• As you move upward through the layers,

atmosphere pressure and density DECREASES – Gases– Nitrogen = 78%– Oxygen = 21%– Trace gases = 1% (Argon, Carbon dioxide, ozone)

II

What is our atmosphere made of?

• Solids– Dust – picked up off of the ground– Salt – picked up from ocean spray– Pollen - produced by plants

• Liquids– Water vapor = up to 4%– Sulfuric acid from volcanoes and air pollution

II

What are the 5 layers of our atmosphere?

• Lower atmosphere– Troposphere• Layer closest to Earth• Approx 11 km high• Weather occurs here• Temperature decreases

with altitude• Contains 99% of the

water vapor and 75% of the atmospheric gasses

III

Hurricane Ivan 2004


• Lower atmosphere

– Stratosphere• Extends 10km to 50km• Airplanes fly here• Ozone layer• Temperature increases

with altitude

III


• Upper atmosphere

– Mesosphere• Extends from 50km to 85km• VERY thin and cold• Temperature decreases

with altitude• Meteorites or shooting

stars occur here

III


• Upper atmosphere– Thermosphere• Extends from 80km to 500km• The thickest layer• Named for its high temperature• Temperature increases

with altitude• Space shuttles fly in this area• Auroras or the Northern lights

III


• Upper atmosphere

– Exosphere• Above a height of 500km• This is where the atmosphere merges into space• Contains very few molecules• Satellites are stationed in this area

III

How is the Sun’s energy absorbed?

• 3 things happen to the energy– About 35% is reflected back into the atmosphere – About 15% of the energy is absorbed by the

atmosphere– About 50% of the energy is absorbed by Earth’s

surface

IV

How is the Sun’s heat transferred through the atmosphere?

• Heat flows from higher temperature objects (roads, rocks, water) to objects with lower temperature (atmosphere)

• 3 ways heat is transferred– Radiation– Heat transfer through empty space– Sun’s energy waves/rays

V


• Radiation– Electromagnetic waves directly transport energy

through space– Travels through empty space

VI


• Conduction– Heat transfer between matter– Objects as molecules bump into each other– Air is NOT a good conductor of heat– Least significant is heating the Earth’s

atmosphere

VIIV. How is the Sun’s energy absorbed?


• Convection– Heat transfer by the movement of mass from one

place to another– ONLY takes place in liquids and gases• Warm air because it is less dense (molecules are

spread out)• Cool air because it is more dense (molecules are

closer together)

VI

Remember this?

What is the water cycle?

• A 3 part cycle describing the constant motion of the hydrosphere (all water on Earth Surface) between Earth and the atmosphere

– Evaporation/Transpiration - Radiation from the sun changes liquid on Earth’s surface into a gas which enters Earth’s atmosphere

– Condensation - Water vapor gas that has cooled and changes back into a liquid

– Precipitation - A collection of tiny water droplets from condensation that collide creating larger droplet which fall to Earth

VII

Earth’s Atmosphere. Nebraska Supercell Storm Cloud - Oklahoma.

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