Chapter 17 AtmosphereChapter 17 Atmosphere

Page 365Page 365 What does the photograph show?What does the photograph show? How does the quality of the air in the photograph How does the quality of the air in the photograph

compare to that of your community today?compare to that of your community today? How might the photograph be different if it was How might the photograph be different if it was

taken on the following day?taken on the following day? What makes up the atmosphere?What makes up the atmosphere? How do human activities affect the atmosphere?How do human activities affect the atmosphere?

Chapter 17.1Chapter 17.1

The composition of the Atmosphere The composition of the Atmosphere

The atmosphere in BalanceThe atmosphere in Balance

The early atmosphere of the earth was primarily The early atmosphere of the earth was primarily created through volcanic eruptions.created through volcanic eruptions.

– Consisted mostly of COConsisted mostly of CO22, SO, SO22, H, H22O, and O, and

NitrogenNitrogen Oxygen was thought to have been created in the Oxygen was thought to have been created in the

upper atmosphere by the destruction of water upper atmosphere by the destruction of water molecules through Photosynthesismolecules through Photosynthesis

Today’s atmosphere (99%) is mostly nitrogen and Today’s atmosphere (99%) is mostly nitrogen and oxygenoxygen

Recycling of Atmospheric materialsRecycling of Atmospheric materials

Composition of the atmosphere changes Composition of the atmosphere changes very little because it is an efficient recycling very little because it is an efficient recycling systemsystem

P. 367 Picture explains the OP. 367 Picture explains the O22, CO, CO22, and , and

HH22O cyclesO cycles

A Delicate BalanceA Delicate Balance

The atmosphere may become unbalance The atmosphere may become unbalance by both natural and human origins by both natural and human origins – e.g. COe.g. CO22 levels in Hawaii have rose 16% levels in Hawaii have rose 16%

between 1959 and 1999between 1959 and 1999

Environmental ConsultantEnvironmental ConsultantMedian annual earnings of environmental scientists were Median annual earnings of environmental scientists were

$51,080 in May 2004. The middle 50 percent earned $51,080 in May 2004. The middle 50 percent earned between $39,100 and $67,360. The lowest 10 percent between $39,100 and $67,360. The lowest 10 percent earned less than $31,610, and the highest 10 percent earned less than $31,610, and the highest 10 percent

earned more than $85,940.earned more than $85,940.Median annual earnings of hydrologists were $61,510 in Median annual earnings of hydrologists were $61,510 in May 2004, with the middle 50 percent earning between May 2004, with the middle 50 percent earning between

$47,080 and $77,910, the lowest 10 percent earning less $47,080 and $77,910, the lowest 10 percent earning less than $38,580, and the highest 10 percent earning more than $38,580, and the highest 10 percent earning more

than $94,460.than $94,460.Median annual earnings in the industries employing the Median annual earnings in the industries employing the largest number of environmental scientists in May 2004 largest number of environmental scientists in May 2004

were as follows:were as follows:Federal Government$73,530Management, scientific, and Federal Government$73,530Management, scientific, and

technical consulting services51,190Architectural, technical consulting services51,190Architectural, engineering, and related services49,160Local engineering, and related services49,160Local government48,870State government 46,850government48,870State government 46,850

Chapter 17.2Chapter 17.2

Page 696Page 696 Convert 70°F Convert 70°F Celsius Celsius When is the Fahrenheit Scale used?When is the Fahrenheit Scale used? The Celsius Scale?The Celsius Scale? Which do you prefer?Which do you prefer?

Heat and the AtmosphereHeat and the Atmosphere

Energy from the sun drives the atmosphereEnergy from the sun drives the atmosphere

How Heat MovesHow Heat Moves

RadiationRadiation – transfer of energy through space in the form of – transfer of energy through space in the form of visible lightvisible light– does not require a mediumdoes not require a medium – pass through a vacuum – pass through a vacuum

Conduction – transfer of heat energy by touchConduction – transfer of heat energy by touch– e.g. air bough warm ground becomes warmere.g. air bough warm ground becomes warmer

Convection – Transfer of heat energy in a liquid or gas Convection – Transfer of heat energy in a liquid or gas caused by differences in densitycaused by differences in density– e.g. warm air heated by the surface of earth becomes e.g. warm air heated by the surface of earth becomes

less dense and risesless dense and rises

Heat and TemperatureHeat and Temperature

Temperature – is the measure of the average K.E. Temperature – is the measure of the average K.E. of the atoms in the substanceof the atoms in the substance

Heat is the total KE of all the particles in a Heat is the total KE of all the particles in a substancesubstance– e.g. A tablespoon of water at 100e.g. A tablespoon of water at 100 Celsius has Celsius has

less heat than a cup of water at 100less heat than a cup of water at 100 Celsius Celsius Thermometer is used to measure temperature Thermometer is used to measure temperature

– At sea level water freezes at 0At sea level water freezes at 0 Celsius and Celsius and Boils at 100° CelsiusBoils at 100° Celsius

Structure of the Atmosphere Structure of the Atmosphere

is divided into 4 layers based on is divided into 4 layers based on temperature p. 371temperature p. 371

Troposphere – lowest layer of the Troposphere – lowest layer of the atmosphere where all weather occursatmosphere where all weather occurs

Temperature decreases with heightTemperature decreases with height

Stratosphere – clear dry layer above Stratosphere – clear dry layer above the Tropospherethe Troposphere

Contains the Ozone(OContains the Ozone(O33) Which absorbs UV ) Which absorbs UV

radiationradiation Temperature increases with increased Temperature increases with increased

heightheight

Mesosphere - the 3Mesosphere - the 3rdrd layer layer

Temperature decreases with heightTemperature decreases with height

Thermosphere – 4Thermosphere – 4thth layer layer

very thin and separated by layers of different very thin and separated by layers of different gassesgasses

due to the intense solar radiation due to the intense solar radiation temperature increases with heighttemperature increases with height

contain the ionospherecontain the ionosphere Auroras are formed when electrically chargeAuroras are formed when electrically charge

d particles are attracted to the earth’s polesd particles are attracted to the earth’s poles

Insulation and the AtmosphereInsulation and the Atmosphere

Incoming solar radiation is called insulationIncoming solar radiation is called insulation Earth receives only two-billionths of the suns Earth receives only two-billionths of the suns

raysrays Of 100 units (p. 373) of suns energy 30 Of 100 units (p. 373) of suns energy 30

reflected back into space, 19 Absorbed by the reflected back into space, 19 Absorbed by the atmosphere, 51 absorbed by Earth’s surfaceatmosphere, 51 absorbed by Earth’s surface

Unequal insulation caused temperature Unequal insulation caused temperature differencesdifferences

Discussion – Global Heat BudgetDiscussion – Global Heat Budget

Page 373Page 373 Explain why most of the atmosphere’s heat Explain why most of the atmosphere’s heat

energy comes indirectly from the sun.energy comes indirectly from the sun.

Chapter 17.3Chapter 17.3

Which surface is likely to be hotter on a Which surface is likely to be hotter on a sunny day:sunny day:– A parking lot blacktopA parking lot blacktop– One with crushed white gravelOne with crushed white gravel

Local Temperature VariationsLocal Temperature Variations

Caused by insulation (energy) heats Caused by insulation (energy) heats Earth’s surface and atmosphere Earth’s surface and atmosphere unequallyunequally

Intensity of InsulationIntensity of Insulation

The angle at which the suns rays strike the earth, The angle at which the suns rays strike the earth, the more overhead (90the more overhead (90) the more energy) the more energy

Time of day - Suns rays are closest to vertical at Time of day - Suns rays are closest to vertical at noon. However, the highest temperature occur noon. However, the highest temperature occur later in the day because of time needed for the later in the day because of time needed for the surface to create heat using the insulationsurface to create heat using the insulation

Latitude and equator 90Latitude and equator 90 more insulation where as more insulation where as high latitude sun rays strike at more of an angle high latitude sun rays strike at more of an angle less insulationless insulation

Time of year – mid latitude locations have Time of year – mid latitude locations have higher temperatures in summer because thigher temperatures in summer because the rays are more direct than in winterhe rays are more direct than in winter– Year’s maximum insulation occurs in June Year’s maximum insulation occurs in June

but max temperate are in July, weakest but max temperate are in July, weakest sunlight in December but lowest temps are sunlight in December but lowest temps are in Januaryin January

Cloud Cover – more insulation on clear Cloud Cover – more insulation on clear days because clouds reflect sunlight. days because clouds reflect sunlight. However, they hold the heat in at night.However, they hold the heat in at night.

Heating of Water and LandHeating of Water and Land

Water and land warm up and cool off at different Water and land warm up and cool off at different rates. Water warms more slowly than land and cools rates. Water warms more slowly than land and cools more slowly.more slowly.

– Suns energy penetrates water deeper spreading it outSuns energy penetrates water deeper spreading it out

– Some energy is used in evaporationSome energy is used in evaporation

– Water has a higher specific heatWater has a higher specific heat Different hard surfaces absorb radiation differentlyDifferent hard surfaces absorb radiation differently

– light colored surfaces absorbs less than darklight colored surfaces absorbs less than dark e.g. e.g. blacktop gets warmer than grassblacktop gets warmer than grass

Temperature Maps (p. 377)Temperature Maps (p. 377)

Land heats and cools off faster than water Land heats and cools off faster than water therefore continents are warmer than nearby therefore continents are warmer than nearby oceans in summer and cooler than nearby oceans in summer and cooler than nearby oceans in winteroceans in winter

Isotherm lines on a map connect places of Isotherm lines on a map connect places of equal temperaturesequal temperatures

Chapter 17.4Chapter 17.4

Human impact on the Atmosphere Human impact on the Atmosphere

Common Air PollutantsCommon Air Pollutants

Air Pollution – any airborne gas or particle thAir Pollution – any airborne gas or particle that occurs at a concentration capable of harmat occurs at a concentration capable of harming humans or the environmenting humans or the environment

Clean air act 1970 Identifies 6 key pollutants Clean air act 1970 Identifies 6 key pollutants – CO, NO– CO, NO22, SO, SO22 Pb, O Pb, O33 and particulates and particulates

Acid Rain – Forms when sulfur dioxide and Acid Rain – Forms when sulfur dioxide and nitrogen oxides react with water vapor in the nitrogen oxides react with water vapor in the

air. Then falls out with rain and snowair. Then falls out with rain and snow

Life forms are sensitive to pHLife forms are sensitive to pH pH scale 0-14 each increase is 10x the pH scale 0-14 each increase is 10x the

priorprior Increased Acid has killed off lakes in Increased Acid has killed off lakes in

Canada and in upper New YorkCanada and in upper New York Can also damage limestone structuresCan also damage limestone structures

Smog - Smog - Photochemical Smog - brown Photochemical Smog - brown haze that forms in air pollution with haze that forms in air pollution with nitrogen oxides and hydro carbons nitrogen oxides and hydro carbons

that come mainly from carsthat come mainly from cars

Creates ground level zones – irritant to Creates ground level zones – irritant to lungs and stunts plant growth and yieldslungs and stunts plant growth and yields

Temperature inversion – air at surface is Temperature inversion – air at surface is colder than the air above trapping colder than the air above trapping pollutants close to the groundpollutants close to the ground

Ozone DepletionOzone Depletion

Thought to be caused by Thought to be caused by Chlorofluorocarbons. CFC’S are used in Chlorofluorocarbons. CFC’S are used in aerosols, air conditioners, and solvents that aerosols, air conditioners, and solvents that are banned in the U.S.are banned in the U.S.

Ozone absorbs UV form the sun that Ozone absorbs UV form the sun that cause skin cancer in humanscause skin cancer in humans

Global WarmingGlobal Warming

Green house gases such as COGreen house gases such as CO22 trap heat at the trap heat at the

earth’s surfaceearth’s surface Gasses could be increased form the burning of Gasses could be increased form the burning of

fossil fuels and global deforestation.fossil fuels and global deforestation. Possible effects Possible effects

– Rising seal levelsRising seal levels– Increasing frequency and severity of stormsIncreasing frequency and severity of storms– More frequent heat waves and droughtsMore frequent heat waves and droughts– Relocation of major crop-growing areasRelocation of major crop-growing areas