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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.
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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.
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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
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Upper Layers of Atmosphere
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.
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Upper Layers of Atmosphere
Exosphere - The atmosphere
merges into space in the
extremely thin exosphere. Thisis the upper limit of our
atmosphere.
Outer layer where spaceshuttle orbits.
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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
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