basic natural sciences - earth atmosphere

8/8/2019 Basic Natural Sciences - Earth Atmosphere

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Earths Atmosphere

An envelope of gases that surround the planet


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Lapse Rate= 7C/km

Dry, stable

Logrithmic scale

S tructure of Earths Atmosphere


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Greenhouse


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I f Earths was flat , solar radiation would be the same everywhere

How and Why does Earths Atmosphere Circulate?


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S ummer

Winter

S easons caused by tilt of E arths axis

E arths Tilt also important for distribution of incoming radiation


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Average AL B EDO for whole Earth ~30%

A lbedo is fractionof incoming solar radiation reflected

back to space


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Why is the seasonal change so strong between 45 and 70?


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Low latitude

oceans absorbmore of incomingradiation


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Why does Earths Atmosphere Circulate?

Latitudinal gradient drives atmospheric circulation!


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How does Earths Atmosphere Circulate?


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Warm air can hold much more water than Cold air!

AND: Wet air is less dense than dry air - R IS ES

Saturation Vapor Pressure Curve


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I f Earth didnt spin, Circulation would be simple!

How does Earths Atmosphere Circulate?


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G eneral Atmospheric Circulation

Rotation of E arthcomplicates the picture


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Coriolis Effect

Earths rotation causes points on Equator to move faster

Faster

Faster


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Coriolis Effect

Deflection R IG HT in N. hemisphere, LEFT in S . Hemisphere


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Surface flow of airdeflected like the rocket:

N. Hemisphere mid-latitude winds deflectedright (EA S T).

N. Hemisphere tradesdeflected right(WE S T)


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T ricellular model of atmosphericcirculation explains large scale pattern of deserts on Earth


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H umanInfluence onEarths

AtmosphereACID RAIN

SMOG

OZONE DEPLETION

GLOBAL WARMING


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Compositionof EarthsAtmosphere

Water can be0.3 to 4%

CO2 , CH

4 , NO

2are important TRAC E G ASES


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Human influence onatmospheric chemistry

Atmospheric pollutants dispersed by circulation

Residence time determines impactS hort residence time, regional effects S ulfur dioxide (Acid rain), Nitrogen oxides ( S mog)

Long residence time, global effects Chlorofluorocarbons (Ozone depletion) CO 2, CH 4 - greenhouse warming


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M auna Loa CO 2 record - The Keeling Curve

Global E ffects


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S ynthesis of Northern Hemisphere Temperature Records

The Hockey S tickUsed in 2001 IPCC Report

Gradual cooling --> Unprecedented Warmth


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Effects of Acid Rain on Forests

Nutrient leaching, release of toxic metals


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Acid rain

attackslimestonebuildingsandmonuments


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Stratospheric Ozone

Ozone in the S tratosphere is good ozone Ozone constantly produced/destroyed in

S tratosphere Provides UV shield ( protects from skin cancer)

Chlorofluorocarbons (CFCs) destroy ozone first Cl + O 3 --> ClO + O 2then ClO + O --> Cl + O 2

Global E ffects


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OzoneH oleCl drivenO3 destructionstarts each

spring asS tratospherewarms TO MS


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Fixing Atmospheric PollutionCFCs banned by 13 industrial nations 1989 Annual ozone hole getting smaller, not yet back

to pre-1950s levels

S crubbers added to power plants S O2 converted to Ca S O4 (gypsum)

Reduction in CO 2 emissions OR CO 2 sequestration technologies

basic natural sciences - earth atmosphere

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