Earth’s Atmosphere

Energy Transfer in the Atmosphere

Air Movement

Earth’s AtmosphereAtmosphere is a thin layer of air that forms

a protective covering around the planetImportance of the Atmosphere: Buffer

between space and the solid earthAtmosphere maintain balance between

amount of heat absorbed from the sun and the amount of heat that escapes back into space

Makeup of the AtmosphereEarth’s atmosphere has evolved2 billions ya: little O2, large volcanic

eruption of CO2 and NEarly organisms released O2 when it

utilized sunlight to produce its own foodEventually a layer rich in ozone O3

formed to protect organisms from harmful sun rays

Plants flourished and as by product of photosynthesis, O increased

Gases in the AtmosphereNitrogen (N) 78%Oxygen (O) 21%Water vapor (H2O) up to 4%Argon (Ar) and CO2Atmosphere composition changes slightly

depending on human interruptions to the atmosphereSmog: brown haze formed from O and other

chemicals in presence of sunlightCO2 burned into atmosphere by human activity

Solids and Liquids in AtmosphereDust, salt, and pollen in atmosphere

Water droplets are moved around the atmosphere by air currents

Layers of AtmosphereLower layer composed of troposphere

99% of atmosphere of water vapor and 75% of gases found here

Weather occurs in troposphere which extends 10 km (6 miles) up

Stratosphere extends above troposphere and extends to 50 km (30 miles) and upper layers contain ozone layer

Upper Layer of AtmosphereMesosphere extends 50 and 85 km (30-

50 miles)Thermosphere extends 85 to 500 km

(50-300 miles)Ionosphere is found within the

mesosphere and thermosphere where electrically charged particles are found

Ionosphere allows radio waves to travel across the country to another city

Exosphere has so few of molecules that rocket wings are useless and that rocket blast are used to move the shuttle

Outer space lies farther out

Ozone LayerOzone is an Oxygen compound

found in the stratosphereUnlike the Oxygen we breath which is

O2, ozone is O3Ozone is important to life on earth because it absorbs most of the ultraviolet radiation from the sun

Ultraviolet radiation is one of many types of energy that comes from the sun.

Damage to skin (cancer) occurs from ultraviolet radiation

Atmosphere PressureForce exerted on an area is known as pressure

Gravity pulls air particles to the surface

The pull is greater closer to the surfaceMore gas particles are found at lower levels

As move above surface the pressure is less

Temperature in AtmosphereAs sunlight passes through the layers of

atmosphere, some gases absorb some of the sunlight and some gases don’t, the temperatures at each layer is different

Troposphere: temperature is warmed by warming earth’s surface that is transferred to the troposphereAs you move upward the temperature decreases at a rate of 6.5℃ every km (5.5℉ every mile)

Stratosphere contains the ozone layer that absorbs some of sun’s energy so as you move upward the temperature increases

Temperature in AtmosphereMesosphere: temperature decreases with increasing altitude

Thermosphere and exosphere are the first layers to receive the sun’s raysBecause they are fewer molecules each

molecule have great deal on energy and the temperatures are high

Ozone LayerOzone is an Oxygen compound

found in the stratosphereUnlike the Oxygen we breath which is

O2, ozone is O3Ozone is important to life on earth because it absorbs most of the ultraviolet radiation from the sun

Ultraviolet radiation is one of many types of energy that comes from the sun.

Damage to skin (cancer) occurs from ultraviolet radiation

Cfc’sChlorofluorocarbons (Cfc’s) are

chemicals that destroy ozoneCfc’s is found in refrigerators, air

conditioners, aerosol cans and production of some foam packaging

Destruction is caused when Cl atom combines with O3 and it breaks apart forming O2 depleting O3 in atmosphere

Also the original Cl atom can continue to break apart O3

Ozone holeThe study of the atmosphere above

Antarctica shows changing ozone layers where holes have been seen

Concentrations of Cfc’s since mid 1990’s have been decreasing helping some

http://www.theozonehole.com/

Energy Transfer in Atmopsheresection 2

Heat is energy that flows from an object with a higher temperature to an object with a lower temperature

Energy from the sun reaches earth’s surface and heats it 3 different ways

RadiationConductionConvection

Radiation Radiation is energy that is

transferred in the form of rays or waves

When you face the sun your face is warmed by that direct contact with radiant energy

ConductionConduction is the transfer of

energy that occurs when molecules bump into one anotherEnergy is transferred from warmer

objects to cooler objectsHot sand warms the air directly

above it by conducting heat energy to the atmosphere

Convection Convection is the transfer of heat

by the flow of materialWarm air is less dense and rises, It eventually becomes cooler, more

dense and settles back down to surface

This turning of the atmosphere warms it

radiation/conduction/convection

Water cycleHydrosphere is the sphere of the earth where

water isCould be as a liquid, solid or gasWater evaporates into the atmosphere

where it will eventually cool, condensation occurs (process of changing water vapor to a liquid) and it falls back to surface in form of precipitation

Water vapor in atmosphere is important in weather and climate factors to an area

Yahoo! Video Detail for NASA: The Water Cycle [720p]

Earth’s unique atmosphereAtmosphere on earth holds just the right

amount of sun’s energy for lifeThe sun’s radiation can be absorbed by the

atmosphere or absorbed by land and water, or be reflected into space

Mar’s atmosphere is so thin that the radiation can’t be absorbed and temp range from 35℃ to -170℃

Venus’s atmosphere is so thick that it traps sun’s energy and temp are about 470℃

Air Movementsection 3

Wind is the movement of air from area of higher pressure to an area of lower pressure

Differences in pressure can be caused by uneven heating of the atmosphere

Areas of the earth receive different amount of radiation because of the curvature of the earth

Poles receive less radiation because of the angle of the suns rays and thus have cooler temperatureThe air sinks in these areas and moves along

earth’s surfaceAt equator, suns rays strike earth directly and

warms faster, rises and is replaced by denser colder air creating convection currents

Uneven heating caused by earth’s curved surface

Coriolis EffectCoriolis effect is caused by the rotation of the

earthAffects air and water on earthCauses air and water to appear to turn to the

right in the northern hemisphere, in southern hemisphere it appears to turn left

Distinct wind patterns develop

Coriolis effect

Global WindsDoldrums are areas near equator

where wind doesn’t blow, but rains a lotSailors who relied on winds for their

sails might die of starvation because of lack of wind on ocean fronts

Near the equator you have heating and rising air, creating lower pressure and little wind

Surface windTrade winds develop at around 30˚ north

and south of the equatorAir that rose over the equator traveled aloft

(above at high altitude)drops back down the surface

Air at the surface moves then moves either back toward the equator in trade winds

Some air travels away from equator north (northern hemisphere) to 60˚ N latitude in the prevailing westerlies wind patterns

Polar easterlies are found near poles. In N pole it moves from northeast to southwest

Wind patterns in atmosphere

Winds in Upper TroposphereJet streams (ribbon of air currents aloft) are

boundaries between cold dry polar air and warmer, moist air in south

Pilots use it to aid them and save fuel when travel with stream

Jet streams also help move storms across the country

Local Wind SystemsSea breezes: is created during the day because

solar radiation warms the land more than the water

Heated air is less dense, rises and at ground air is replaced by cooler air from seas. Convection currents occur. You have movement of air from sea to land

Land breezes: At night the air over land cools faster than air over ocean, and that cooler denser air moves toward the ocean. Movement of air toward the water from the land to sea is land breeze