ATMOSPHERE - Santa Monica College

2/27/20072/27/2007 11

ATMOSPHEREATMOSPHERE

GASES, LAYERS, GASES, LAYERS, TEMPERATURESTEMPERATURES

2/27/20072/27/2007 ©© Vicki Drake, SMCVicki Drake, SMC 22

EARTHEARTH’’S ATMOSPHERE FROM S ATMOSPHERE FROM SPACESPACE


COMPONENTS OF THE GLOBAL COMPONENTS OF THE GLOBAL CLIMATE SYSTEMCLIMATE SYSTEM


WHAT IS THE ATMOSPHERE?WHAT IS THE ATMOSPHERE?

§§ The atmosphere is a gaseous realmThe atmosphere is a gaseous realm

§§ Humans live at the bottom of an Humans live at the bottom of an ‘‘ocean of ocean of airair’’

§§ Atmospheric conditions can exert an Atmospheric conditions can exert an influence on the Earthinfluence on the Earth’’s surfaces surface


ORIGIN OF EARTHORIGIN OF EARTH’’S S ATMOSPHEREATMOSPHERE

§§ Original atmosphere developed approximately 4.6 billion Original atmosphere developed approximately 4.6 billion years agoyears ago–– Two main gases: Helium and HydrogenTwo main gases: Helium and Hydrogen–– Water vapor (HWater vapor (H22O)O) and Nitrogen (N) introduced laterand Nitrogen (N) introduced later

§§ Water Vapor sourcesWater Vapor sources–– OutgassingOutgassing from volcanoes introduced water vapor (Hfrom volcanoes introduced water vapor (H22O)O)§§ Water trapped in mantle rocks percolated to the surfaceWater trapped in mantle rocks percolated to the surface§§ Condensation and precipitation formed worldCondensation and precipitation formed world’’s oceans ocean

-- Other possible water source: Comets and MeteorsOther possible water source: Comets and Meteors

§§ Nitrogen introduced soon after Helium and HydrogenNitrogen introduced soon after Helium and Hydrogen


CONTEMPORARY ATMOSPHERECONTEMPORARY ATMOSPHERE§§ Contemporary atmosphere developed approximately 3.5Contemporary atmosphere developed approximately 3.5--2.4 Billion 2.4 Billion

years ago with introduction of a toxic, corrosive and explosive years ago with introduction of a toxic, corrosive and explosive ((‘‘combustiblecombustible’’) gas: OXYGEN (O) gas: OXYGEN (O22))–– Released by photoReleased by photo--dissociation of Hdissociation of H22OO–– Produced by BlueProduced by Blue--green algae (green algae (StromatolitesStromatolites))

§§ Oxygen constituted a wholesale pollution of the environment; Oxygen constituted a wholesale pollution of the environment; a "holocaust" for all living things on Earth.a "holocaust" for all living things on Earth.

§§ Oxygen needed for ozone shield protecting Earth surface from Oxygen needed for ozone shield protecting Earth surface from damaging ultradamaging ultra--violet raysviolet rays–– Ozone shielding allowed Ozone shielding allowed ‘‘lifelife’’ to move into shallow water and eventually to move into shallow water and eventually

onto land.onto land.

§§ Oxygen buildOxygen build--up allowed the appearance of the first up allowed the appearance of the first eukaryotic cells (PLANTS, FUNGI, AND ANIMALS)eukaryotic cells (PLANTS, FUNGI, AND ANIMALS)

§§ Eukaryotic cells require oxygen for their more complicated and mEukaryotic cells require oxygen for their more complicated and more ore efficient metabolism. efficient metabolism.


COMPOSITION OF ATMOSPHERECOMPOSITION OF ATMOSPHERE

§§ Permanent GasesPermanent Gases–– Nitrogen Nitrogen –– 78% by volume78% by volume–– Oxygen Oxygen –– 21% by volume21% by volume–– Remaining gases Remaining gases -- <1% by volume<1% by volume§§ ArgonArgon§§ NeonNeon§§ HeliumHelium§§ HydrogenHydrogen§§ XenonXenon§§ KryptonKrypton


COMPOSITION OF ATMOSPHERECOMPOSITION OF ATMOSPHERE§§ Variable Gases (Also Greenhouse GasesVariable Gases (Also Greenhouse Gases))

–– Water Vapor Water Vapor –– 00--4% by volume4% by volume–– Carbon Dioxide (COCarbon Dioxide (CO22) ) –– 0.035% (350 parts per million)0.035% (350 parts per million)–– Methane (CHMethane (CH44) ) -- 0.00017% (0.17 0.00017% (0.17 ppmppm))–– Nitrous Oxide (NNitrous Oxide (N22O) O) –– 0.00003% (0.03 0.00003% (0.03 ppmppm))–– Ozone (OOzone (O33) ) –– 0.000004% (0.004 0.000004% (0.004 ppmppm))–– Chlorofluorocarbons (CFCs) Chlorofluorocarbons (CFCs) –– 0.00000001% (0.00001 0.00000001% (0.00001 ppmppm))

§§ Particulates Particulates –– airborne solidsairborne solids–– Windblown dustWindblown dust–– Salt crystals from oceansSalt crystals from oceans–– AerosolsAerosols§§ Solid or liquid particles less than 100 microns diameterSolid or liquid particles less than 100 microns diameter

–– Volcanic AshVolcanic Ash–– Condensation aerosolsCondensation aerosols§§ Formed by condensations of vapor or reactions of gases Formed by condensations of vapor or reactions of gases

–– Smoke/SootSmoke/Soot§§ Forest firesForest fires§§ IndustriesIndustries


GREENHOUSE EFFECTGREENHOUSE EFFECT§§ Energy from the sun (shortEnergy from the sun (short--wave energy) heats the Earthwave energy) heats the Earth’’s s

surfacesurface§§ The Earth radiates longThe Earth radiates long--wave wave ““infraredinfrared”” energy back into energy back into

space. space. §§ Absorption of EarthAbsorption of Earth’’s longs long--wave radiation by some wave radiation by some

atmospheric gases add additional heat energy to the atmospheric gases add additional heat energy to the atmospheric system. atmospheric system.

§§ Warmer atmospheric greenhouse gas molecules radiate longWarmer atmospheric greenhouse gas molecules radiate long--wave energy in all directions. wave energy in all directions.

§§ Over 90 % of this emission of longOver 90 % of this emission of long--wave energy is directed wave energy is directed back to the Earth's surface, where it once again is back to the Earth's surface, where it once again is absorbed by the surface absorbed by the surface

§§ Without Without ““greenhouse effect,greenhouse effect,”” the heat would escape to the heat would escape to outer space outer space –– Average temperature of the Earth would drop from an Average temperature of the Earth would drop from an

average of +15average of +15 degrees Celsius to degrees Celsius to --1818 degrees degrees Celsius! Celsius!

–– Life as we know it could not surviveLife as we know it could not survive


GREENHOUSE EFFECTGREENHOUSE EFFECT


GREENHOUSE GASES GREENHOUSE GASES –– CARBON CARBON DIOXIDE (CODIOXIDE (CO22))

§§ CARBON DIOXIDE (COCARBON DIOXIDE (CO22))§§ A colorless, odorless gas, denser than airA colorless, odorless gas, denser than air

–– Absorbed and stored in vegetation during photosynthesisAbsorbed and stored in vegetation during photosynthesis–– Stored in worldStored in world’’s oceans by s oceans by phytoplanktonsphytoplanktons§§ CarbonateCarbonate

–– Main component of chalk, shells, coral reefs, limestoneMain component of chalk, shells, coral reefs, limestone

–– Released:Released:§§ Respiration Respiration –– animal life (all forms)animal life (all forms)§§ Volcanic eruptionsVolcanic eruptions§§ Deforestation Deforestation –– 35% of global CO35% of global CO22

–– Conversion of forested lands, prairies and woodland into agriculConversion of forested lands, prairies and woodland into agricultural landstural lands–– Natural release due to decay of dead vegetationNatural release due to decay of dead vegetation

§§ Burning of fossil fuels Burning of fossil fuels –– 65% of global CO65% of global CO22–– Oil, Natural Gas, CoalOil, Natural Gas, Coal


RESPIRATIONRESPIRATION§§ Respiration is a key component Respiration is a key component

of the global carbon cycle.of the global carbon cycle.–– Plant respirationPlant respiration–– Animal respirationAnimal respiration

§§ However, the direct contribution However, the direct contribution to atmospheric carbon dioxide to atmospheric carbon dioxide concentrations via respiration is concentrations via respiration is relatively insignificant relatively insignificant

§§ Of more concern is the impact Of more concern is the impact humanhuman--induced global warming induced global warming could have on global respiration could have on global respiration rates. rates.

§§ Increasing temperatures means Increasing temperatures means rates of respiration may also rates of respiration may also increase in many organisms.increase in many organisms.


Volcanic Eruptions Volcanic Eruptions –– COCO22 EmissionsEmissions§§ COCO22 is the second most is the second most

abundant gas released abundant gas released during volcanic eruptionsduring volcanic eruptions

§§ Concentrated COConcentrated CO22emissions kill vegetation, emissions kill vegetation, animals and even humans animals and even humans near volcanic openingsnear volcanic openings

§§ Volcanoes emit between Volcanoes emit between about 145about 145--255 million tons 255 million tons of COof CO22 into the into the atmosphere every year atmosphere every year –– Emissions by human Emissions by human

activities contribute about 24 activities contribute about 24 billion tons every yearbillion tons every year


DEFORESTATION DEFORESTATION –– COCO22


DEFORESTATION DEFORESTATION –– CAUSES AND CAUSES AND CONSEQUENCESCONSEQUENCES

§§ Deforestation due to:Deforestation due to:–– Logging Logging §§ timber or pulptimber or pulp

–– Agricultural purposes Agricultural purposes §§ Cultivation: Cultivation:

–– SlashSlash--Burn Burn agricultureagriculture

§§ Cattle grazingCattle grazing–– World demand for World demand for

beefbeef§§ Consequences:Consequences:

–– Increased carbon dioxide Increased carbon dioxide (CO(CO22) and other trace gases ) and other trace gases in the atmosphere in the atmosphere

–– 460460--575 billion 575 billion metric tons of carbon metric tons of carbon stored in tropical stored in tropical forests worldwide forests worldwide


FOSSIL FUEL CONSUMPTIONFOSSIL FUEL CONSUMPTION


COCO22 FOSSIL FUEL SOURCESFOSSIL FUEL SOURCES§§ Emissions per ton of Emissions per ton of

oil equivalent or oil equivalent or ““toetoe””(1 toe = 11600 kWh (1 toe = 11600 kWh = the energy freed = the energy freed by the combustion of by the combustion of one ton of oil )one ton of oil )

U.S. CO2 Emissions vs. World

California Fossil Fuel CO2

Emission Sources


FOSSIL FUEL CONSEQUENCESFOSSIL FUEL CONSEQUENCES


FOSSIL FUEL CONSEQUENCESFOSSIL FUEL CONSEQUENCES

§§ COCO22 is used as a common denominator, and is used as a common denominator, and values of other gases are expressed in COvalues of other gases are expressed in CO2 2 equivalentsequivalents§§ COCO2 2 may contribute to global warmingmay contribute to global warming§§ Future carbon dioxide levels are expected to Future carbon dioxide levels are expected to

continue rising due to ongoing fossil fuel continue rising due to ongoing fossil fuel usageusage


METHANE (CHMETHANE (CH44))

§§ CHCH4 4 is released in the decay process of is released in the decay process of organic materialorganic material§§ Most common sources:Most common sources:

–– WetlandsWetlands–– Bacteria in rice paddiesBacteria in rice paddies§§ Wet anaerobic soilsWet anaerobic soils

–– Biochemical reactions in stomach of ruminants Biochemical reactions in stomach of ruminants and termitesand termites

–– LandfillsLandfills


TABLE OF METHANE SOURCES TABLE OF METHANE SOURCES ––TgCHTgCH44

544.9542.3546.7554.2557.3569.3579.5605.3Total for U.S.

0.80.70.80.80.80.80.80.7Agricultural Residue Burning

111.11.21.21.21.31.3Iron and Steel

1.51.51.41.71.71.71.61.2Petrochemical Production

2.72.93.13.43.63.944.8Mobile Sources

6.46.46.97.77.37.28.16.1Abandoned Coal Mines

6.76.46.77.37.16.97.47.8Stationary Sources

6.96.87.67.58.37.97.57.1Rice Cultivation

17.117.117.417.617.818.518.820Petroleum Systems

36.835.834.734.333.632.631.724.8Wastewater Treatment

39.139.338.938.138.838.836.431.2Manure Management

53.852.455.656.258.962.862.681.9Coal Mining

115114.6114.5115.6116.8116.7118.3117.9Enteric Fermentation

125.9130.6131.8132.1127.4131.8133.6128.3Natural Gas Systems

131.2126.8126.2130.7134138.5147.4172.2Landfills

20032002200120001999199819971990Source Category


METHANE METHANE -- WETLANDSWETLANDS

§§ The largest sources of The largest sources of methane are the methane are the wetlands of the worldwetlands of the world§§ OneOne--fifth of all fifth of all

methane is emitted by methane is emitted by wetlandswetlands


RICE PADDIESRICE PADDIES§§ More than 60 % of all rice More than 60 % of all rice

paddies are found in India and paddies are found in India and China where scientific data China where scientific data concerning emission rates are concerning emission rates are unavailable.unavailable.

§§ Contribution of rice paddies is Contribution of rice paddies is large because this form of crop large because this form of crop production has more than production has more than doubled since 1950. doubled since 1950. –– At between 50 and 100 million At between 50 and 100 million

tons of methane a year, rice tons of methane a year, rice agriculture is a big source of agriculture is a big source of atmospheric methaneatmospheric methane§§ (possibly the biggest of man(possibly the biggest of man--

made methane sources) made methane sources)


BIOCHEMICAL SOURCES OF BIOCHEMICAL SOURCES OF METHANEMETHANE


METHANE and LIVESTOCKMETHANE and LIVESTOCK§§ Methane emission from ruminant livestock is Methane emission from ruminant livestock is

currently estimated to be around 100 million currently estimated to be around 100 million tons each year tons each year §§ Methane is produced in the guts of ruminant Methane is produced in the guts of ruminant

livestock as a result of livestock as a result of methanogenicmethanogenicbacteria and protozoa. bacteria and protozoa. –– After rice agriculture, represents the biggest After rice agriculture, represents the biggest

manman--made methane sourcemade methane source–– Sheep can produce about 30 liters of methane Sheep can produce about 30 liters of methane

each day and a dairy cow up to about 200. each day and a dairy cow up to about 200.


METHANE AND TERMITESMETHANE AND TERMITES§§ Global emissions of termites Global emissions of termites

account for approximately 11% account for approximately 11% of the global methane emissions of the global methane emissions from natural sources. from natural sources.

§§ Methane is produced in termites Methane is produced in termites as part of their normal digestive as part of their normal digestive process, and the amount process, and the amount generated varies among generated varies among different species. different species.

–– Termites produce methane in their gut as Termites produce methane in their gut as they digest woody plant material they digest woody plant material

§§ Ultimately, emissions from Ultimately, emissions from termites depend largely on the termites depend largely on the population of these insects, population of these insects, which can also vary significantly which can also vary significantly among different regions of the among different regions of the world. world.


METHANE AND LANDFILLSMETHANE AND LANDFILLS§§ In a landfill, biogenic waste is In a landfill, biogenic waste is

consumed by aerobic bacteriaconsumed by aerobic bacteria§§ After oxygen is depleted, After oxygen is depleted,

anaerobic bacteria take overanaerobic bacteria take over§§ Through fermentation Through fermentation

processes, methane is producedprocesses, methane is produced§§ Methane must be released Methane must be released

carefully carefully –– it is an explosive gasit is an explosive gas–– A grid system of perforated A grid system of perforated

pipes connected to vacuum pipes connected to vacuum blowers collect and remove the blowers collect and remove the gas. gas.

–– The landfill gas is either burned The landfill gas is either burned off in a flare, or used to off in a flare, or used to generate electricity in a gas generate electricity in a gas turbine turbine


NITROUS OXIDE (NNITROUS OXIDE (N22O)O)

§§ NN22O forms in the soil as a result of bacteria and microbes O forms in the soil as a result of bacteria and microbes interactionsinteractions

§§ Sources include landSources include land--use conversion; fossil fuel use conversion; fossil fuel combustion; biomass burning; and soil fertilization combustion; biomass burning; and soil fertilization

§§ PRIMARY SOURCE: deforestation and the conversion of PRIMARY SOURCE: deforestation and the conversion of forest, savanna and grassland ecosystems into agricultural forest, savanna and grassland ecosystems into agricultural fields and rangeland fields and rangeland –– The use of nitrate and ammonium fertilizers to enhance plant The use of nitrate and ammonium fertilizers to enhance plant

growth is another source of nitrous oxide.growth is another source of nitrous oxide.§§ SECONDARY SOURCE: the presence or absence of SECONDARY SOURCE: the presence or absence of

control devices on combustion sources, such as catalytic control devices on combustion sources, such as catalytic converters on automobiles, can have a significant effect on converters on automobiles, can have a significant effect on the level of Nthe level of N22O emissions. O emissions.


NITROUS OXIDE TABLE NITROUS OXIDE TABLE –– TgNTgN22OO

376.7380.5385.9402.2382.1407.8396.2382Total for U.S.

0.40.40.40.40.50.40.30.1Remaining Forest Land

0.40.40.50.50.40.50.40.4Agricultural Residue Burning

0.50.50.40.40.30.30.40.4Waste Combustion

4.84.84.84.84.84.84.84.3N2O Product Usage

65.94.965.5610.315.2Adipic Acid

665.866.26.16.15.5Remaining Settlements

13.813.513.51413.513.413.512.3Stationary Sources

15.817.215.919.620.120.921.217.8Nitric Acid

15.915.715.615.615.41514.713Human Sewage

17.517.91817.817.417.417.316.3Manure Management

42.145.64953.254.655.355.243.7Mobile Sources

253.5252.6257.1263.9243.4267.7252253Agricultural Soil Management

20032002200120001999199819971990Source Category


NITROUS OXIDE SOURCESNITROUS OXIDE SOURCES

Natural sources: 10 million tons/yr

Man-made sources: 8 million tons/yr


NITROUS OXIDE (NNITROUS OXIDE (N22O CYCLE)O CYCLE)


NITROUS OXIDE NITROUS OXIDE –– CATALYTIC CATALYTIC CONVERTERCONVERTER

§§ Nitrous oxide comprises Nitrous oxide comprises 7.2% of global warming 7.2% of global warming gases.gases.

§§ Cars and trucks, most Cars and trucks, most fitted with catalytic fitted with catalytic converters, produce nearly converters, produce nearly half of that gashalf of that gas

§§ Nitrous oxide is produced Nitrous oxide is produced during the reaction of during the reaction of nitrogen oxide (NO) and nitrogen oxide (NO) and ammonia (NH3) over the ammonia (NH3) over the platinum in the catalytic platinum in the catalytic converter converter


OZONE OZONE –– OO33

§§ Ozone is formed naturally by chemical Ozone is formed naturally by chemical combination of Ocombination of O22 and O in the presence of and O in the presence of sunlightsunlight§§ Ozone is a form of Photochemical pollution in Ozone is a form of Photochemical pollution in

lower atmospherelower atmosphere§§ Ozone forms a protective layer in upper Ozone forms a protective layer in upper

atmosphereatmosphere–– Maximum Ozone concentration found approximately 30 Maximum Ozone concentration found approximately 30

kilometers above surface of Earthkilometers above surface of Earth–– The ozone layer in the acts like a giant sunshade, The ozone layer in the acts like a giant sunshade,

protecting plants and animals from much of the sun's protecting plants and animals from much of the sun's harmful ultraviolet radiation. harmful ultraviolet radiation.


OZONE IN ATMOSPHEREOZONE IN ATMOSPHERE


DECLINE IN STRATOSPHERIC DECLINE IN STRATOSPHERIC OZONEOZONE

§§ Global stratospheric ozone levels have declinedGlobal stratospheric ozone levels have declined–– Significant evidence of a thinning of the ozone layer during sprSignificant evidence of a thinning of the ozone layer during spring ing

and summerand summer

§§ Chlorofluorocarbons (CFCs), Chlorofluorocarbons (CFCs), halonshalons, methyl chloroform, , methyl chloroform, methyl bromide, methyl bromide, carbontetrachloridecarbontetrachloride and several other and several other chemicals are ozonechemicals are ozone--depleting substancesdepleting substances–– When CFCs and When CFCs and halonshalons are released into the atmosphere, they rise are released into the atmosphere, they rise

slowly, taking up to seven years to reach the stratosphere. slowly, taking up to seven years to reach the stratosphere. –– Under the influence of the sun's ultraviolet light, chlorine is Under the influence of the sun's ultraviolet light, chlorine is released released

and reacts with ozone, with a depletion of the ozone layer as a and reacts with ozone, with a depletion of the ozone layer as a consequence. consequence. §§ This allows harmful solar UV radiation to pass through to the eaThis allows harmful solar UV radiation to pass through to the earth's rth's

surface surface §§ Some of the ozone depleting substances are persistent, remainingSome of the ozone depleting substances are persistent, remaining

active in the atmosphere for up to 50 years. active in the atmosphere for up to 50 years.


OZONE AND CFCSOZONE AND CFCS


CHLOROFLUOROCARBONS CHLOROFLUOROCARBONS (CFCS)(CFCS)

§§ CFCs are manCFCs are man--made compounds created for the made compounds created for the following purposes:following purposes:–– PropellantsPropellants§§ Hair spray, deodorant, spray paintHair spray, deodorant, spray paint

–– RefrigerationRefrigeration§§ Freon in refrigerators, freezers, air conditionersFreon in refrigerators, freezers, air conditioners

–– SolventsSolvents§§ Cleaning materials Cleaning materials –– especially dry cleanersespecially dry cleaners

–– InsulationInsulation–– Exhaust from some aircraftExhaust from some aircraft§§ SSTs SSTs ‘‘ConcordeConcorde’’


HOLE IN OZONE LAYERHOLE IN OZONE LAYER§§ An ozone "hole" is what scientists An ozone "hole" is what scientists

call an "ozone depletion area" in call an "ozone depletion area" in that region of Earth'sthat region of Earth's atmosphereatmosphere–– The depletion area usually appears The depletion area usually appears

with the southern hemisphere with the southern hemisphere spring (August spring (August -- October)October)

§§ The 2003 ozone hole covered 11.1 The 2003 ozone hole covered 11.1 million square miles, making it the million square miles, making it the second largest ever recorded second largest ever recorded

§§ The 2005 hole covered about 10 The 2005 hole covered about 10 million square miles million square miles

§§ While the ozone hole may appear While the ozone hole may appear for as much as 40 more years, it is for as much as 40 more years, it is expected to improve expected to improve

§§ Consequences: UV radiation Consequences: UV radiation exposureexposure


PARTICULATESPARTICULATES


PARTICULATES SOURCESPARTICULATES SOURCES

§§ Particulates introduced directly into the air Particulates introduced directly into the air can originate from natural fires, volcanic can originate from natural fires, volcanic eruptions, the ejection of salt crystals by eruptions, the ejection of salt crystals by breaking ocean wavesbreaking ocean waves–– and as any sufferer of hay fever can tell you, by and as any sufferer of hay fever can tell you, by

the entrainment of pollen by wind.the entrainment of pollen by wind.§§ Human activities, especially those involving Human activities, especially those involving

combustion, produce primary and secondary combustion, produce primary and secondary particulates. particulates.


HEALTH ISSUESHEALTH ISSUES§§ Fine particulates are so small Fine particulates are so small

that they can easily be inhaled that they can easily be inhaled into the deepest reaches of our into the deepest reaches of our lungs, causing serious lung and lungs, causing serious lung and heart disease. heart disease. –– Fine particulates are linked with Fine particulates are linked with

all sorts of health problems all sorts of health problems ——from a runny nose and from a runny nose and coughing, to bronchitis, coughing, to bronchitis, emphysema, asthma and even emphysema, asthma and even death. death.

§§ Fine particulates are also a Fine particulates are also a visual blight, capable of visual blight, capable of reducing visibility so much that reducing visibility so much that beautiful views are blotted out beautiful views are blotted out

Electronmicrograph of flyash: trash incineration


ATMOSPHERE LAYERSATMOSPHERE LAYERS§§ Troposphere: 0Troposphere: 0--11 km11 km

–– TropopauseTropopause§§ Stratosphere: 18Stratosphere: 18--50 km50 km

–– StratopauseStratopause§§ Mesosphere: 55Mesosphere: 55--90 km90 km

–– MesopauseMesopause§§ Thermosphere: 95 kmThermosphere: 95 km--

200km? 400km?200km? 400km?§§ ExosphereExosphere§§ IonosphereIonosphere


LOWER ATMOSPHERE LOWER ATMOSPHERE --TROPOSPHERETROPOSPHERE

§§ The lowest layer of the atmosphereThe lowest layer of the atmosphere–– All weather occurs here: clouds, winds, storms, etcAll weather occurs here: clouds, winds, storms, etc

§§ Extends to an average of 11 kilometers above the Extends to an average of 11 kilometers above the surfacesurface–– Higher elevation near equatorHigher elevation near equator–– Lower elevation near polesLower elevation near poles

§§ Temperature decreases at a consistent rate in the Temperature decreases at a consistent rate in the tropospheretroposphere§§ TropopauseTropopause –– upper boundary of troposphereupper boundary of troposphere

–– No temperature change in this boundaryNo temperature change in this boundary


UPPER ATMOSPHEREUPPER ATMOSPHERE

§§ STRATOSPHERE STRATOSPHERE –– the beginning of the upper the beginning of the upper atmosphere at approximately 20 kilometers above atmosphere at approximately 20 kilometers above surfacesurface–– Extends to 50 kilometersExtends to 50 kilometers

§§ Ozone layer Ozone layer –– concentration at 30 kilometers concentration at 30 kilometers above surfaceabove surface§§ Temperature increases in this layer as UV Temperature increases in this layer as UV

radiation is absorbed by ozoneradiation is absorbed by ozone§§ StratopauseStratopause is the uppermost boundaryis the uppermost boundary

–– No temperature change in this boundaryNo temperature change in this boundary



§§ MESOSPHERE MESOSPHERE –– begins at approximately begins at approximately 55 kilometers above surface55 kilometers above surface–– Extends to approximately 90 kilometersExtends to approximately 90 kilometers

§§ Atmosphere very thin, temperatures Atmosphere very thin, temperatures decrease with elevationdecrease with elevation§§ MesopauseMesopause is uppermost boundaryis uppermost boundary



§§ THERMOSPHERE THERMOSPHERE –– beginning at 95 beginning at 95 kilometers above surfacekilometers above surface§§ Temperature increases due to molecular Temperature increases due to molecular

Oxygen absorbing solar radiationOxygen absorbing solar radiation§§ Exosphere Exosphere –– the final boundary between the final boundary between

EarthEarth’’s atmosphere and outer spaces atmosphere and outer space


IONOSPHEREIONOSPHERE§§ Not a true layer of atmosphere Not a true layer of atmosphere –– extends throughout much extends throughout much

of upper atmosphereof upper atmosphere§§ An electrified region consisting of An electrified region consisting of IONS IONS

–– Ions are atoms that have lost or gained electronsIons are atoms that have lost or gained electrons

§§ The visible manifestation of the highThe visible manifestation of the high--energy ions is seen in energy ions is seen in the auroras, the colorful Northern and Southern Lights that the auroras, the colorful Northern and Southern Lights that appear at 90 to 160 kilometers above Earth appear at 90 to 160 kilometers above Earth

–– The light is emitted when charged particles from the sun are guiThe light is emitted when charged particles from the sun are guided ded by the earth's magnetic field into the atmosphere near the polesby the earth's magnetic field into the atmosphere near the poles..

–– When the particles contact atmospheric molecules, primarily When the particles contact atmospheric molecules, primarily oxygen and nitrogen, at altitudes from 300 km down to 100 km, a oxygen and nitrogen, at altitudes from 300 km down to 100 km, a part of the energy of the collisions transforms to visible lightpart of the energy of the collisions transforms to visible light..


AURORA BOREALIS AND AURORA AURORA BOREALIS AND AURORA AUSTRALISAUSTRALIS


MAGNETOSPHERE AND AURORASMAGNETOSPHERE AND AURORAS§§ The sun spews out charged The sun spews out charged

particles traveling at a million miles particles traveling at a million miles per hour known as the solar wind.per hour known as the solar wind.–– Charged particles, mostly protons Charged particles, mostly protons

and electrons, emitted from the and electrons, emitted from the outer region of the Sun (corona) outer region of the Sun (corona) reach the magnetosphere of Earth reach the magnetosphere of Earth having a velocity of some 350 to having a velocity of some 350 to 400 kilometers per second. 400 kilometers per second.

§§ Particles which stream out of Particles which stream out of sunspots may be captured by the sunspots may be captured by the Earth's magnetic field and create Earth's magnetic field and create the aurora. the aurora. –– Electrons and protons collide with Electrons and protons collide with

the gas particles in the outer the gas particles in the outer atmosphere atmosphere

–– The excited electrons return to their The excited electrons return to their ‘‘normalnormal’’ states by emitting light of states by emitting light of distinct wavelength and thus a distinct wavelength and thus a distinct color distinct color

Documents

ATMOSPHERE - Santa Monica College