1 Our atmosphere Important mixture of gases that sustain life on Earth Important mixture of gases...

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Our atmosphereOur atmosphere

Important mixture of gases that Important mixture of gases that sustain life on Earthsustain life on Earth

480km (300 miles) thick480km (300 miles) thick Beyond the atmosphere is the Beyond the atmosphere is the

EXOSPHEREEXOSPHERE Contains small quantities of Contains small quantities of

hydrogen and heliumhydrogen and helium

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Major Major componentcomponent

s of the s of the troposphertropospher

ee

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Major Atmospheric Major Atmospheric ComponentsComponents

NitrogenNitrogen Originates mostly from volcanic sourcesOriginates mostly from volcanic sources Without nitrogen there would be no lifeWithout nitrogen there would be no life

OxygenOxygen By-product of photosynthesisBy-product of photosynthesis Concentration of oxygen varies with Concentration of oxygen varies with

latitudelatitude

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ArgonArgon Constitutes almost 1% of the Constitutes almost 1% of the

atmosphereatmosphere Not necessary for life but it used for Not necessary for life but it used for

some economic purposessome economic purposes Carbon dioxideCarbon dioxide

By-product of lifeBy-product of life Important for keeping atmosphere warmImportant for keeping atmosphere warm

increases in COincreases in CO22 can cause an increase in can cause an increase in atmospheric temperatureatmospheric temperature

Water vaporWater vapor Variable from near 0 – 4 %Variable from near 0 – 4 %

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The The AtmospheAtmospheric Profileric Profile

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The AtmosphereThe Atmosphere

The troposphere

The stratosphere

The mesophere

The thermosphere

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The Troposphere The Troposphere (weathersphere)(weathersphere)

Water vapor, clouds, pollution, and Water vapor, clouds, pollution, and life occur within the tropospherelife occur within the troposphere

~ 18km (11 miles) thick at equator; ~ 18km (11 miles) thick at equator; 12 km (8 miles) thick in the mid-12 km (8 miles) thick in the mid-latitudes; and 8km (5 miles) thick latitudes; and 8km (5 miles) thick near the polesnear the poles

Top of troposphere known as the Top of troposphere known as the tropopausetropopause

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Lapse Rates in the Lapse Rates in the TroposphereTroposphere

As we go upwards in As we go upwards in the troposphere, the the troposphere, the temperature decreasestemperature decreases 6.4°C/1km or 6.4°C/1km or

3.5°F/1000ft = AVERAGE3.5°F/1000ft = AVERAGE This number is not that This number is not that

importantimportant

Can vary considerably Can vary considerably with varying weather with varying weather conditions and conditions and locationslocations

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The stratosphereThe stratosphere

Temperatures increase from -57°C at Temperatures increase from -57°C at the base of the stratosphere to O°C at the base of the stratosphere to O°C at the top (50km above Earth’s surface)the top (50km above Earth’s surface)

Why?Why?

Top of the stratosphere is called the Top of the stratosphere is called the StratopauseStratopause

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The mesophereThe mesophere 50 – 80 km above 50 – 80 km above

Earth’s surfaceEarth’s surface Outer boundary known Outer boundary known

as the mesopauseas the mesopause Temperature drops Temperature drops

from O°C to - 90°C at from O°C to - 90°C at the mesopausethe mesopause

Occasional Occasional coalescence of cosmic coalescence of cosmic and meteoric dust and meteoric dust form cloudsform clouds

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The thermosphereThe thermosphere

Upper surface Upper surface known as the known as the thermopausethermopause

Temperatures Temperatures increase to increase to ~1200°C at the ~1200°C at the thermopausethermopause

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AtmospheAtmospheric ric

functionfunction

Two main Two main zoneszones The The

ozonosphereozonosphere The ionosphereThe ionosphere

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Functions Functions of the of the

atmospheatmospherere

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Ozonosphere and Ozonosphere and IonosphereIonosphere

OZONOSPHEREOZONOSPHERE Contains a high level Contains a high level

of ozoneof ozone

Efficiently absorbs UV Efficiently absorbs UV wavelengths of energywavelengths of energy

Ozone is being Ozone is being depleted due to depleted due to human activityhuman activity Recent reboundRecent rebound

IONOSPHEREIONOSPHERE Efficiently absorbs Efficiently absorbs

cosmic, gamma, x-cosmic, gamma, x-rays, and UV rays, and UV wavelengths of wavelengths of energyenergy

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All the Earth’s All the Earth’s energy ultimately energy ultimately comes from the suncomes from the sun

Weather and climate Weather and climate are ultimately driven are ultimately driven by by The energy gain from The energy gain from

the sunthe sun The Earth’s position The Earth’s position

relative to the sunrelative to the sun Electromagnetic Electromagnetic

spectrumspectrum Mr. ROY G BIVMr. ROY G BIV

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HOW TO REMEMBER THE HOW TO REMEMBER THE ORDER OF VISIBLE LIGHTORDER OF VISIBLE LIGHT

ROY G BIVROY G BIV REDRED ORANGEORANGE YELLOWYELLOW GREENGREEN BLUEBLUE INDIGOINDIGO VIOLETVIOLET

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Solar radiation and Earth’s Solar radiation and Earth’s re-radiationre-radiation