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