TheThe EaEartrthh’s’s AtAtmomosphsphereere
Earth’Earth’ss AtmospAtmospheherree
AtmospAtmospherehere isis thethe gaseougaseouss layerlayer thatthat surrsurroundsounds thethe eeartharth
IsIs aa mixmixtureture ofof ggasesases tthathat isis nanaturturallallyy odorodorlleess,ss, colourcolourless,less, tastetastelessless andand forformlessmless
AiAirr isis blendblendeded soso thorthoroughlyoughly tthathat itit behavebehavess asas ifif itit wweerere aa singlesingle ggasas
ThThee AtAtmospmospheherere
AiAirr isis heldheld toto tthehe earearthth bbyy thethe forceforce ofof ggravity:ravity:
TThehe furfurtherther awayaway frfromom thethe ssoourceurce ofof ggravitatravitatiiononalal attrattractionaction (e(eartharth)) ththee lowerlower thethe aattrattractictioonalnal forforcece MoMorere airair molecmoleculesules araree heldheld clclososerer toto thethe earearthth ththanan atat highehigherr elevaelevatitioonsns AtmosphAtmosphereere isis mormoree dedensense nenearar ththee sursurfaceface tthanhan atat highhigherer elevatioelevationsns
ThThee AtAtmospmospheherere
NoNo rerealal “t“top”op” –– atmatmospherospheree ddriftsrifts ofofff toto nothingnothingnessness aabovebove aboaboutut 101000 kmkm
97%97% ofof tthehe weighweightt andand 100%100% ofof tthehe watewaterr vapovaporr reresisiddee iinn thethe bottbottomom 3300 kmkm
DDensiensittyy
TThhee dendensisittyy (m(massass perper ununiitt volume)volume) ofof thethe atmoatmossppherehere quicklyquickly decrdecreaseseases wwithith iinncreacreassiningg elevatelevatiioonn aboaboveve seasea llevevelel
DensityDensity ofof thethe atmoatmoss cancan bebe mmeasureeasuredd asas iitt exexertertss itsits weightweight asas aa ppressurressuree ((forceforce perper unitunit aarea)rea) TThehe prpressureessure thethe atmoatmoss exexertertss onon tthehe sursurfaceface iiss knowknow asas airair pressupressurere . Air pressure at sea levell == 1013 mb . Air pressure at the top of the stratosphere (50km) = 0.78 mb
CCompoompositionsition ofof thethe aattmomosphespherere
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Oxygen – O2 21% Animals
Together, Nitrogen and Oxygen account for 99% of the atmosphere, by volume!
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Oxygen – O2 21% Animals Argon – Ar 0.93% Inert Gas
93% of the remaining 1% is Argon, an inert gas!
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Oxygen – O2 21% Animals Argon – Ar 0.93% Inert Gas
Carbon Dioxide – CO2 0.0325% Plants
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Oxygen – O2 21% Animals Argon – Ar 0.93% Inert Gas
Carbon Dioxide – CO2 0.0325% Plants Neon – Ne 0.0005% Inert Gas
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Oxygen – O2 21% Animals Argon – Ar 0.93% Inert Gas
Carbon Dioxide – CO2 0.0325% Plants Neon – Ne 0.0005% Inert Gas Krypton – Kr 0.0001% Inert Gas
Proportion of Elements in Dry Air (by volume)
Nitrogen – N2 78% Plants
Oxygen – O2 21% Animals Argon – Ar 0.93% Inert Gas
Carbon Dioxide – CO2 0.0325% Plants Neon – Ne 0.0005% Inert Gas Krypton – Kr 0.0001% Inert Gas
Hydrogen – H2 0.00005% Helium – He <0.00001% Inert Gas Xenon – Xe <0.00001% Inert Gas
Methane – CH4 <0.00001%
The Atmosphere
Water Vapor H2O 0 to 4%
Ozone O3 0.0 to 0.0012% Chlorofluorcarbons – CFCs (e.g., Freon) Changing Concentrations of: . Ozone . Carbon Dioxide . Methane . Water Vapor Climate Change!
ImImpoportanrtantt RRoolesles PPllayayeded bbyy TTrracacee GGaasseses
CarbCarbonon DioxDioxideide . AnAn impoimportanrtantt absoabsorberrber ofof outgooutgoiinngg terterrestrrestrialial raradiationdiation
. It,It, alongalong withwith waterwater vaporvapor,, serserveve asas thethe prprimarimaryy memeansans ofof prevepreventingnting rrapidapid heheatat lossloss ffromrom thethe eartearthh anandd atmatmospheospherere babackck intointo sspacepace
ImImpoportanrtantt RRoolesles PPllayayeded bbyy TTrracacee GGaasseses
Water Vapor - . An important absorber of outgoing terrestrial energy
. Amounts vary from 0 to 4% depending on of evaporating water available and distance that source
. This can cause tremendous differences in temperatures within the atmosphere
http://weather.unisys.com/satellite/sat_wv_us.html
ImImpoportanrtantt RRoolesles PPllayayeded bbyy TTrracacee GGaasseses
Liquid Water – . Causes clouds to form… this affects the amount of heat absorbed by the earth and atmosphere
. Can vary tremendously within the atmosphere
IInsnsololatiationon loslossesses iinn ththee aatmtmososppherheree Dust - Gas molecules, dust, and other particulates are important because they can cause the sun’s rays to be scattered or absorbed
Scattering - visible light rays to be turned aside in all possible directions. Under clear sky conditions, scattering sends about 5% of the incoming solar radiation back to space.
Absorption - Solar rays strike gas molecules and dust, and their energy is absorbed and temperatures rise. This accounts for about a 15% decrease in solar radiation.
Both carbon dioxide and water vapor are capable of directly absorbing some wavelengths of solar radiation.
ElElectromagectromagnenettiicc RRadiadiatioationn
EEleclectromagnetitromagneticc rradiationadiation ccanan be:be:
AbAbsosorrbedbed –– increincreasesases ththee eneenergyrgy concontenttent ofof ththee obobjject,ect, liklikee aa bbllackack carcar iinn thethe ssuummemmerr RefleReflectectedd –– bbounceounce thethe eenergnergyy backback ttowardoward thethe sosource,urce, liklikee aa mmiirrrorror TTrrananssmimittettedd –– ppassass ththroughrough wwitithouthout absorpabsorptiontion oror rereflfleectictioon,n, likelike aa panepane ofof ggllaassss
EElelectromctromagagnetineticc RadRadiiationation AlbAlbedoedo –– percpercentent ooff solarsolar/shor/shortwtwaaveve rradiationadiation tthathat iiss rereflfleectedcted ffromrom aa sursurface.face.
NewNew snow:snow: 80%80% OOlldd SSnnow:ow: 50%50% Clouds:Clouds: 50%50% IIce:ce: 35%35% Dark,Dark, wweett soil:soil: 5%5% LLiigght,ht, ddryry sosoiil:l: 40%40% AsAspphalt:halt: 5%5% ForeForest:st: 15%15% GrGrass:ass: 20%20% CrCrops:ops: 20%20%
WaterWater –– hhiigghh incidentincident angleangle 50%50% WaterWater –– lowlow incideincidentnt ananglegle 5%5%
AAververageage albedalbedoo ofof thethe earearth’sth’s ssuurfacerface:: 7%7%
ElectromElectromagagnetneticic RadRadiatioiationn
TThehe atmospheratmospheree isis generagenerallylly trtransanspaparrentent toto shorshortwatwavvee radradiationiation andand opaqueopaque toto lolongngwavwavee
THTHEE GGRREEEENNHHOUOUSSEE EEFFFFECECTT
Vertical Distribution of the Atmosphere
TThhee TTroroposppospheherere
LayeLayerr ofof thethe atmoatmospheresphere inin concontacttact withwith thethe susurfacerface TTememperperaturaturee decrdecreaseseases withwith heightheight bbecauseecause tthehe trtroposphoposphereere isis heatheateded frfromom belowbelow ((atmoatmospherspheree isis gengenerallyerally trtranspaansparentrent toto shshortwaveortwave radiaradiation)tion) LayeLayerr ththatat concontainstains allall weathweatherer andand aallll cloucloudsds ExExtetendsnds toto abouaboutt 1122 ttoo 1515 km;km; actualactual heightheight varvariieess wiwitthh latitudelatitude andand seasonseason (th(thiickeckerr asas temptemperatueraturere iinnccrreaseeasess)) MuMucchh waterwater vaporvapor andand dudustst –– fromfrom iinnterateractionsctions wiwitthh thethe surfsurfaceace
ContainContainss abouaboutt 80%80% ofof thethe massmass ooff thethe atmatmospherospheree
VVeerticalrtical DisDistrtribuibutiotionn ofof thethe AtmoAtmossphphereere
ThThee TropTropopopauausese
Small,Small, isothisothermermalal layerlayer aboveabove thethe ttroposropospherpheree
IsothIsothermermalal –– nnoo temtemperaperaturturee chanchangege withwith heheightight
AboutAbout 1212 toto 1515 kmkm iinn heheiigghtht –– actuaactuall heighheightt varvariieess wiwitthh latitudelatitude andand seasonseason
VVeerticalrtical DisDistrtribuibutiotionn ofof thethe AtmoAtmossphphereere
TheThe StratospStratospherehere
LayeLayerr ofof thethe atmoatmospheresphere aboabovvee thethe trotroposphepospherere TTememperperaturaturee increaincreasesses wwitithh hheighteight becaubecausese ooff
absoabsorptionrption ofof uullttravioletraviolet lighlightt byby oozzoonene ((OO3)) ExExtetendsnds upup toto aaboutbout 5050 kmkm inin heighheightt LittleLittle exexchanchangege ofof airair bbetweenetween troptropospherospheree aandnd strstratosphatosphereere –– littlelittle dusdustt oror waterwater vaporvapor
StableStable airair llaayeryer –– llittittllee verticalvertical mmotionsotions bbecauseecause ofof ththee increincreasingasing temtemperperaturaturee withwith hheieigghtht ---- inverinversionsion
VVeerticalrtical DisDistrtribuibutiotionn ofof thethe AtmoAtmossphphereere
TheThe StStraratopatopauseuse
SSmallmall,, iisothersothermamall lalayeryer ababooveve thethe strstratospheratospheree IsotherIsothermalmal –– nono tempertemperatatuurere cchahanngege wiwithth heightheight
AAboutbout 5050 kmkm inin heheiightght
VVeerticalrtical DisDistrtribuibutiotionn ofof thethe AtmoAtmossphphereere
TThhee MesospMesospheherere
LayeLayerr ofof thethe atmoatmospheresphere aboabovvee thethe strastratosphetospherere
TTememperperaturaturee ddecreaecreasesses withwith heightheight becausbecausee ofof aa lacklack ofof ccoontactntact wwitithh thethe grogroundund aandnd aa lalackck ofof ozozoneone
ExExtetendsnds upup toto aaboutbout 8080 kmkm inin heighheightt
VVeerticalrtical DisDistrtribuibutiotionn ofof thethe AtmoAtmossphphereere
TThhee MMeesopsopauseause
Small,Small, isothisothermermalal layerlayer aboveabove thethe mmesosphesosphereere
IsothIsothermermalal –– nnoo temtemperaperaturturee chanchangege withwith heheightight
AboutAbout 8080 kmkm iinn heightheight
VVeerticalrtical DisDistrtribuibutiotionn ofof thethe AtmoAtmossphphereere
TThhee TThhermospermospheherere
LayeLayerr ofof thethe atmoatmospheresphere aboabovvee thethe mesosmesospherpheree TTememperperaturaturee increaincreasesses withwith heheiigghtht becabecauseuse ofof eenergnergyy frfromom gammgammaa anandd xx-ra-rayy absoabsorptionrption duedue ttoo thethe earearth’sth’s mamagneticgnetic fiefielldd (van(van AAllenllen radiatradiatiioonn belt)belt) DensityDensity ofof airair aatt thisthis alalttitudeitude isis vveeryry ththinin andand thethe thethermosrmospherpheree holdsholds littlittllee heatheat
TThehermrmospherospheree esseessentiallyntially driftdriftss offoff ttoo notnothingnehingnessss aboaboveve aboaboutut 121200 kmkm
LaLapspsee RRaatestes::
TTeempermperatuaturere dedecreacreasseess wiwitthh increincreasingasing aallttiitutudede withinwithin tthehe trtroposphoposphereere atat anan averaverageage rrateate ofof 6.6.44 C/kmC/km
6.46.4 C/kmC/km == NormNormalal LapsLapsee RateRate
TThhee actactualual decrdecreaseease iinn temtemp,p, oror actuactualal llaapsepse rrateate maymay varvaryy consideconsiderablyrably ffromrom thethe normnormalal lapse:lapse: enviroenvironmennmentaltal lapselapse raratete
PolPolluluttiionon
TThehe atmoatmospherspheree isis mamadede upup ofof ttwwoo zoneszones basedbased iinn funcfunctitioon:n: toto rrememoovvee haharmfurmfull wawavelveleengthngthss ofof ssoollaarr rradiationadiation aandnd cchhaargergedd paparticlesrticles
IonospIonospherehere OzonospOzonospherehere
Extends throughout the ozone llayer that is wiithin the
thermopause and iinto stratosphere that containins O3 underlyinglying mesosphere Higighlyly reactiveive to oxygen Absorbs cosmic rays, gamma molleculeles rays, x-rays, and shorter Ozone is harmfull to living wavelelengths of UV rad creatures when present near the Absorptiion changes atoms to surface +ve charged ioions ~ ionosphere Is necessary as absorbs harmfull wavelelengths of UV rad and reradiates itit as safer LW rad
OOzonezone DDeeplepletiotionn
CFCFC’s-C’s- CChlohloroflurroflurocarocarbonsbons
--becambecamee wiwiddelyely usedused iinn thethe 19201920ss forfor iinndustrdustryy --valvaluuableable aass propropellpellaantsnts foforr aaerosoerosoll ssppraysrays aandnd asas refrrefrigeraigerantsnts --alsalsoo usedused iinn industindustryry asas sosolventslvents anandd fofoamingaming agentagentss Good for industry as were not flalammablele Cannot be broken down by atmospheriic processes near the earth’s surface Not water soluble and do not break down by biologicic proceprocesses Can be broken down by UV radiation wiithin the stratosphere --CCFCFC’s’s migramigratete toto thethe stratstratospherospheree overover timetime
BBrereakakddowownn ooff CCFCFCss fromfrom UUVV raradiadiatiotionn
SeparaSeparatestes singsingllee ClCl atomatomss oror cchhlorinelorine monomonoxxideide (ClO)(ClO) momolleeccuulesles frfromom tthehe CFCFCC comcomponponentsents
OzonOzonee isis anan unstabunstabllee molecumolecullee (O(O2 oror OO3)) ChlorineChlorine isis aa catacatalystlyst forfor thethe destrdestructionuction ofof ozonozonee One Cl atom can decompose 100,000 ozone molelecules Cl atoms have a resiidence time wiithinin thethe ozoozone layer of 40-100yrs.
ExExaamplemple ooff ozonozonee brbreakdoeakdowwn…n………
191970s70s –– noticednoticed ddepletionepletion inin levelslevels ofof ozoneozone,, studstudiieses intointo tthehe effeffectect ofof chemchemiicacallss onon ozoozonene depdepletionletion 19197878 –– USUS bbannedanned CCFC’FC’ss iinn aeraerosolsosols butbut waswas stillstill usedused iinn rerefrigerfrigerantsants andand ppolyolyuuretrethanehane foamfoam 19198181 –– bannbanneedd CFCFCC prproductoductss stillstill aalllloowweedd toto bebe exexpoportertedd 19198585 –– BBrriittiisshh AntAnt SurveySurvey reporeportedrted ozoneozone holehole ooverver AAntntarcticaarctica 19198787 –– peakpeak inin CCFCFC salessales sincesince aeroaerosolsol banban (1.3(1.322 millionmillion tontons)s) 19199090 (1(1992992 && 11997)997) –– MoMontrntrealeal ProtocProtocolol toto rreduceeduce useuse ooff CFCFC’sC’s globagloballlyly 19199898 –– prodproductionuction ooff CFCFC’sC’s declinedeclinedd toto 1/41/4th thathatt ofof tthehe 11987987 peapeakk
PPoollutllutionion
AiAirr PollPolluutiontion –– anan uunwantednwanted substsubstanceance injinjecectedted intintoo thethe atmatmospheospherere ffromrom thethe eartearth’sh’s surfsurfaceace byby eithereither natunaturalral oror humhumanan aactivictivittiieess . Come as aerosols, gases or particiculalates
Aerosols – smallll bitsbits ofof matter iin the airir that move freelyly wiith normall airir movements
Gases – moleculalar compounds mixed together to form airir
Partiiculates – larger, heavier partiicles that sooner or later fallll baback to the surface (haze, smoke, dust)
SourSourcceses ofof AirAir PollPollutiutionon
NaturNaturalal –– pproduroducece grgreateat qquantuantiitiesties ofof ppollollututantsants tthanhan hhumaumann soursourcesces Volcanoes, forest fires, plants, soil,l, and ocean Produce NOx, CO, HCx and CO2
AnthrAnthropogeopogenicnic –– aalltthoughhough lessless ththanan natnaturalural sosources,urces, humhumansans havehave yetyet ttoo adaadaptpt toto anthanthropogropogenicenic popolllutlutiioonn asas fforor nnaturaturalal Sources includlude every day actiivitiesities by large numbers of people (cars!) Industrial burning of fossil fuelsls andand ore smeltining
CarbCarbonon MMonoxonoxideide -- conconsissisttss ofof oneone cacarbonrbon andand oneone oxoxygygenen atoatomm incompincompletelete cocombustmbustiioonn ofof fossilfossil fuelsfuels 90%90% prproduceoducedd byby nnaturaturalal soursourcesces (d(decayecay ofof carbcarbonon soursourcesces –– wowood)od) 10%10% ananthrothropogenpogeniic,c, mainlymainly cacarsrs Source of CO for indivivididualsls isis ffiirst and second hand tobacco and smoke
PhotoPhotocchhemicalemical SmoSmogg –– intinteraeraccttiioonsns ofof sunlightsunlight aandnd comcombustionbustion prodproductsucts inin aautomutomobileobile exexhauhaustst (NOx(NOx aandnd VOC’VOC’s)s) . Result of inincreased automobilele usage over the past century
SmogSmog –– comcombinationbination ofof smsmokeoke aandnd fofogg . Aerosolsls and gas pollllutants inin urban areas . Lets iin light but can obscure objects iin the sky . Irrititates eyes and throat – diffiicultlt to breathe . Corrodes structures over time
AcidAcid PrecipitatPrecipitatiionon –– aatmosphtmosphericeric acidacidss broubroughtght ttoo thethe surfsurfaceace byby pprecipitatrecipitatiioonn (r(rain,ain, snosnow)w) oror byby drdryy dudustst . Major source of SOx from industriall emissioions
. Acidid rainin = rainin/snow pollulluted witith SO2 or NO2 . Acidid dust = sulflfuric and nitric nucllei clinling to dust particleles Fall to earth and coat surface Increase the acidityity of soilil wiith wet Accumulalate wiith snow and meltlt iin spring as surge of acid water
HazeHaze –– humhumidid airair causescauses aa filmfilm ofof waterwater toto atattachtach toto aeaerosolrosol parparticlticleess mamakikinngg thethemm larlargege enoenoughugh toto scatscatterter lighlightt andand rereduceduce visibilityvisibility . Natural and anthropogenicic sources . Soilil dust, saltlt crystalsls, pollelen, smoke
NNataturaurall FFaacctotorsrs AffeAffecctingting PolluPollutiontion
WindWind –– movemove pollutantpollutantss frofromm ononee arareaea ttoo anotanotherher
. Pollllutiion Dome – dome of pollulutioion over an urban area under calm,lm, stable atmospheric conditioions . Pollllutiion Plume – plume of pollllutiion originatiing over an urban area that isis transported downwinind from its urban source
ButBut it’sit’s nonott allall bad!bad!
CleanClean AAirir AActct ((19701970)) –– lleeadad toto decrdecreaseease iinn pollutantpollutantss andand increincreasease inin huhumanman healthhealth . Decrease in cancer rates . Less acid rain . 206,000 fewer deaths from aiir polllulutioion iin 1990