The AtmosphereThe Atmosphere
CompositionComposition
NitrogenNitrogen OxygenOxygen OtherOther
– ArgonArgon– Carbon DioxideCarbon Dioxide– MethaneMethane– Water VaporWater Vapor
Atmospheric dustAtmospheric dust
NitrogenNitrogen Most abundantMost abundant 78%78% Volcanoes eruptVolcanoes erupt Dead plants and Dead plants and
animals decayanimals decay
OxygenOxygen 22ndnd most most
abundantabundant about 21%about 21% Produced by Produced by
plantsplants
Atmospheric DustAtmospheric Dust Mostly soilMostly soil SaltSalt Ash from firesAsh from fires Volcanic firesVolcanic fires Explosion matterExplosion matter People bits- skin, hair, People bits- skin, hair,
bits of clothingbits of clothing PollenPollen Bacteria & VirusesBacteria & Viruses AerosolsAerosols- tiny liquid - tiny liquid
dropletsdroplets
Air PressureAir Pressure Atmosphere pulled by Atmosphere pulled by
gravitygravity THUS THUS denser near denser near
Earth’s surfaceEarth’s surface Most Earth’s Most Earth’s
atmospheric gases atmospheric gases located located within 30 km within 30 km of surfaceof surface
Why is it harder to Why is it harder to breathe at higher breathe at higher elevations?elevations?
LayersLayers TroposphereTroposphere
– 18 km above Earth’s 18 km above Earth’s surfacesurface
StratosphereStratosphere– 18-50 km18-50 km
MesosphereMesosphere– 50-80 km50-80 km
ThermosphereThermosphere– 80-550 km80-550 km
TroposphereTroposphere
Nearest EarthNearest Earth Almost all weather Almost all weather
occurs hereoccurs here Densest layerDensest layer
– Why?Why?
Temperature Temperature decreases as altitude decreases as altitude increaseincrease
StratosphereStratosphere Temperature rises as Temperature rises as
altitude risesaltitude rises Contains ozone layerContains ozone layer
– absorbs UV radiationabsorbs UV radiation reduces amount reduces amount
of UV radiation of UV radiation hitting the surfacehitting the surface
– How does this How does this help us?help us?
Ozone absorbs UV Ozone absorbs UV energy & warms airenergy & warms air
OzoneOzone- molecule made - molecule made of three oxygen atomsof three oxygen atoms
MesosphereMesosphere
Coldest layerColdest layer Temperatures Temperatures
have reached -93° have reached -93° CC
ThermosphereThermosphere
Nitrogen & Oxygen Nitrogen & Oxygen absorb UV radiationabsorb UV radiation
2,000°C2,000°C Would not feel hotWould not feel hot
– VERY THINVERY THIN– particles rarely collide to particles rarely collide to
transfer heattransfer heat
Lower ThermosphereLower Thermosphere N & O atoms in lower N & O atoms in lower
thermosphere thermosphere absorb absorb harmful solar harmful solar radiationradiation (X & gamma (X & gamma rays)rays)
IonsIons- - electrically electrically charger particlescharger particles
seen in North and seen in North and South PolesSouth Poles
IonosphereIonosphere
LayersLayers
Energy in the AtmosphereEnergy in the Atmosphere
RadiationRadiation- - transfer of transfer of energy across spaceenergy across space
ConductionConduction -flow of -flow of energy from direct energy from direct conduct of a conduct of a warmer object to warmer object to a cooler objecta cooler object
ConvectionConvection- - transfer of transfer of heat from air currentsheat from air currents
EnergyEnergy Solar energy reaches Solar energy reaches
Earth as electromagnetic Earth as electromagnetic radiationradiation– Visible LightVisible Light– Infrared RadiationInfrared Radiation– Ultraviolet LightUltraviolet Light
Only two BILLIONTHS of Only two BILLIONTHS of sun’s energy reach Earthsun’s energy reach Earth
Energy AbsorptionEnergy Absorption
Only Only HALFHALF of the solar of the solar energy that enters energy that enters atmosphere reaches atmosphere reaches Earth’s surfaceEarth’s surface
Other half:Other half:– Absorbed or reflected by Absorbed or reflected by
clouds, gases, or dustclouds, gases, or dust– Reflected by Earth’s Reflected by Earth’s
surfacesurface
Why does the Earth just Why does the Earth just get hotter and hotter?get hotter and hotter?
HeatingHeating Oceans and land Oceans and land radiate the energy they have radiate the energy they have
absorbed BACK into the atmosphereabsorbed BACK into the atmosphere Dark colored objects absorb more than light Dark colored objects absorb more than light
colored objectscolored objects Cities tend to be hotter in temperature than Cities tend to be hotter in temperature than
countrysidecountryside
Movement of Energy in AtmosphereMovement of Energy in Atmosphere Hotter air=less Hotter air=less
densedense Cooler air=more Cooler air=more
densedense Air is heatedAir is heated rises rises Air cools Air cools falls falls Convection Convection
Currents:Currents: rising and rising and falling of air with the falling of air with the heating and coolingheating and cooling
Greenhouse EffectGreenhouse Effect
Sunlight enters Sunlight enters atmosphere, heat atmosphere, heat is radiated back, is radiated back, some escapes, some escapes, REST is absorbed REST is absorbed by greenhouse by greenhouse gases and gases and radiated back to radiated back to surfacesurface
Greenhouse GasesGreenhouse Gases
Trap and radiate heatTrap and radiate heat Not a high concentration Not a high concentration
of them in atmosphereof them in atmosphere Abundant gases:Abundant gases:
– Water vaporWater vapor– Carbon dioxideCarbon dioxide– MethaneMethane– Nitrous oxideNitrous oxide
Carbon dioxide and Carbon dioxide and methane results from methane results from industrial processesindustrial processes