9. Atmosphere 1

8/12/2019 9. Atmosphere 1

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Atmosphere


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Solar Energy as Radiation

Nearly 150 million kilometers separate the sun and earth, solar

radiation drives earth's weather.


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Earth's Atmosphere

The atmosphere is a thin layer of air that protects the Earths

surface from extreme temperatures and harmful sun rays

Thin Gaseous envelope


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Composition of Atmosphere(Mixture of gases, solids, and liquids)

Early atmosphere was much different thantoday

Volcanoes produced nitrogen and carbon

dioxide, but little oxygen More than 2 billion years ago, early

organisms began producing oxygen

Eventually, oxygen formed an ozone layer

that protected Earth from harmful rays Green plants and diverse life forms

developed


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Atmospheric Gases(Mixture of gases, solids, and liquids)

Nitrogen - 78%

Oxygen - 21%

Water Vapor0 to 4%

Used for clouds and precipitation Carbon Dioxide - .037%

Keeps Earth warm and is used byplants to make food

Argon - .93% Traces of neon, helium, methane,krypton, xenon, hydrogen, and ozone


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Atmospheric Gases(Mixture of gases, solids, and liquids)

Atmosphere is changing with theintroduction of pollutants; increasinghuman energy use is increasing theamount of carbon dioxide

Pollutants mix with oxygen and otherchemicals to form smog

Aerosols include solids such as

dust, salt, and pollen Liquids include water droplets and

droplets from volcanoes


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Five Layersof the

Atmosphere


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Lower Layers of Atmosphere

Troposphere: lowest layerextendsup to 10km; contains 99% of the watervapor and 75% of the atmosphericgases

The troposphereis the first layer abovethe surface and contains most cloudsand half of the Earth's atmosphere.

Weather occurs in this layer. Most of the layers heat is from Earth

Temperature cools about 6.5degrees Celsius per kilometer of

altitude.
http://www.windows2universe.org/earth/Atmosphere/troposphere.htmlhttp://www.windows2universe.org/earth/Atmosphere/troposphere.html


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Lower Layers of Atmosphere

Stratospheredirectly abovetroposphere, extending from 10 km toabout 50 km above Earths surface

Portion of the upper layer containshigh levels of a gas called ozone

Many jet aircrafts fly in thestratospherebecause it is verystable.

The ozone layer absorbs harmfulrays from the Sun.
http://www.windows2universe.org/earth/Atmosphere/stratosphere.htmlhttp://www.windows2universe.org/earth/Atmosphere/stratosphere.html


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Upper Layers of Atmosphere

Mesosphereextends from the

top of the stratosphere to about 85

km above Earth

Coldest layer with little ozone

Meteors or rock fragments burn

up in the mesosphere.

Ionosphere herelayer of

charged particles
http://www.windows2universe.org/earth/Atmosphere/mesosphere.htmlhttp://www.windows2universe.org/earth/Atmosphere/mesosphere.html


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Thermospherethickest atmosphericlayer found between 85 km and 500 kmabove Earths surface

The thermosphereis a layer withauroras, known for its hightemperatures.

Warms as it filters out X-rays and

gamma rays from the Sun Ionosphere here, toohelp carry

radio waves.
http://www.windows2universe.org/earth/Atmosphere/thermosphere.htmlhttp://www.windows2universe.org/earth/Atmosphere/thermosphere.html


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Exosphere - The atmosphere

merges into space in the

extremely thin exosphere. Thisis the upper limit of our

atmosphere.

Outer layer where spaceshuttle orbits.
http://www.windows2universe.org/earth/Atmosphere/exosphere.htmlhttp://www.windows2universe.org/earth/Atmosphere/exosphere.html


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Layers of

Atmosphere


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Atmospheric Pressure

Molecules closer to the

surface are more densely

packed (at higher pressure)together than those higher in

the atmosphere because of the

mass of gases pressing downon them from higher in the

atmosphere


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Temperature in atmospheric layers

The troposphere is warmed primarily bythe Earths surface; temperaturedecreases as altitude increases in this

layer. Temperatures increase as altitude

increases in the stratosphere, particularlyin the upper portionozone

Temperatures decrease with altitude in themesosphere

Thermosphere and exosphere are the first

to receive Suns rays, so they are very hot


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The Ozone Layer

About 19 km to 48 km above Earth in thestratosphere (90%) and troposphere (10%).

Layer of 3-atom molecules that protects the

Earth from the Suns harmful ultraviolet radiation Life depends on the ozone!

Pollutants called chlorofluorocarbons (CFCs) aredestroying the ozone

CFCs are used in refrigerators, air conditioners,aerosol sprays, and foam packaging ~ ifproducts leak, CFCs enter atmosphere

Ozone layers has a large hole over Antarctica

and a smaller one over the North Pole


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Some of the Sunsenergy coming

through Earths

atmosphere isreflected or absorbed

by gases and/or

clouds in the

atmosphere.


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Greenhouse Effect

Solar energy that isabsorbed by the Earths

land and water is

changed to heat thatmoves/radiates back into

the atmosphere

(troposphere) wheregases absorb the heat, a

process known as the

greenhouse effect.


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Heat

Energy that flows from an object with a highertemperature to an object with a lowertemperature

Heat is transferred through the atmosphere by: Radiation:energy that is transferred in the form of raysor waves

Conduction:energy that is transferred when moleculesbump into each other

Convection:energy that is transferred by flow ofmaterial

Molecules move closer together, making air moredense, and air pressure increases

Cold air sinks, pushing up warm air, which thencools and sinks ushin u more warm air


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Water Cyclewater makes up 70%

of Earths surface!!


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Water Cycle

Water moves back and forth between Earthsatmosphere and surface

Energy from the sun causes water to evaporatefrom the hydrosphere and rise as vapor

Sun provides water cycles energy Water on the surface absorbs heat and evaporates,

entering the atmosphere

Condensationwater vapor changes back into liquid

Clouds of water become heavy and water falls to Earthas precipitation

The cycle repeats itself continuously


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Rain & Drizzle- mostcommon type ofprecipitation.

Freezing Rain- drizzle fromstratus clouds.

Freezing Rain- raindropsfreeze when they hit theground.

Sleet- raindrops that freezebefore they hit the ground.


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snow- as ice grows and

merges into clouds theyform snowflakes.

hail- is the largest type

of precipitation.

Lumps or balls of ice

that fall from

cumulonimbus clouds in

warm weather.


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Lets take a look at the weather

picture and why we have weather!


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What is Weather?

State of the atmosphere at a specific time andplace

Includes such conditions as air pressure, wind,

temperature, and moisture in the air Temperature is a measure of air moleculemovement

Suns energy causes air molecules to move

rapidly; temperatures are high and it feelswarm

When less of the Suns energy reaches airmolecules, they move less rapidly and it feels

cold


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What is Weather?

Energy is transferred between fast-moving

molecules and slower-moving molecules

CONDUCTIONtransfer of energy

when molecules collide

CONVECTIONoccurs when warm air

rises and cool air sinks; its the transfer

of heat, usually in liquids or gases


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After the atmosphere is warmed byradiation and conduction, the heat is

transferred throughout the atmosphere byconvection. Since warmed air

has more spacebetween the

molecules, itsless dense andrises

Cooled air is moredense and tendsto sink

In general, airnear the equatortends to rise and

air near the polestends to sink


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Take a look at this!


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Notice the band ofclouds around the

equator ?

This is the ITCZor intertropical convergence zone


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Why do you think there is this bandof clouds near the equator?


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Humidity

The amount of water vapor in the air

Temperature affects how much moisture is inthe air - warmer air can hold more watervapor, tending to make it more humid

Relative humiditythe amount of water vaporin the air compared to what it can hold at aspecific temperature

When air cools, it cant hold as much watervapor, so the water vapor condenses to liquidor forms ice crystals

Dew pointthe temperature at which air is

saturated and condensation forms

9. Atmosphere 1

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