THE ATMOSPHERETHE ATMOSPHERE

Chapter 15Chapter 15

Earth’s atmosphereEarth’s atmosphere

Extends ABOUT 100 Extends ABOUT 100 miles ( ? Km) above miles ( ? Km) above the surfacethe surface

COMPOSTITION OF COMPOSTITION OF ATMOSPHEREATMOSPHERE

cynobacteriacynobacteria

Produced first oxygenProduced first oxygen

Atmospheric pressureAtmospheric pressure

• Gravity pulls the air Gravity pulls the air molecules toward the earth, molecules toward the earth, giving them weight. giving them weight.

• This is called theThis is called the atmospheric pressureatmospheric pressure..

High elevations = lower pressureHigh elevations = lower pressure

Low elevations = higher pressureLow elevations = higher pressure

As As elevation elevation goes up,goes up,

air air pressure pressure

goes down.goes down.

This is an inverse This is an inverse relationshiprelationship..

At which location would the air pressure be the least?The Great Divide

elev. = 10,759 ft.

the Nambian Desert

elev. = 825 ft.

the Kona coast

elev. = 0 ft.

Mt. Everest

elev. = 29,028 ft.

Mauna KeaMauna Kea

Why are the colors in this order?Why are the colors in this order?

Layers of atmosphereLayers of atmosphere

Layers of the AtmosphereLayers of the Atmosphere

TroposphereTroposphere– Where weather occursWhere weather occurs– Temperature DECREASES Temperature DECREASES

with altitude with altitude – Ground absorbs heat-Ground absorbs heat-

Heated from bottom upHeated from bottom up

coldhot

STRATOSPHERESTRATOSPHERE

Warms with altitudeWarms with altitude Planes fly in this layerPlanes fly in this layer Contains ozone layerContains ozone layer

– Absorbs solar radiation Absorbs solar radiation (heat)(heat)

– Filters UV raysFilters UV rays– CFC’s destroy ozoneCFC’s destroy ozone

RefrigerationRefrigeration StyrofoamStyrofoam Air conditionersAir conditioners

OZONE LAYEROZONE LAYER

Thinning over AntarcticaThinning over Antarctica Allows more UVAllows more UV

– Skin cancerSkin cancer– CataractsCataracts– Stunts plant growthStunts plant growth

Ozone “hole” over AntarcticaOzone “hole” over Antarctica

Peaks in Oct.Peaks in Oct.

Ozone LayerOzone Layer

Cl attacks OCl attacks O33 and splits and splits

it apartit apart Chlorine doesn’t get Chlorine doesn’t get

destroyeddestroyed

MESOSPHEREMESOSPHERE

Cools with altitude Cools with altitude (farther from ozone (farther from ozone layer)layer)

Meteors burn up in this Meteors burn up in this layerlayer

THERMOSPHERETHERMOSPHERE

Absorbs harmful radiation Absorbs harmful radiation – x-rays & gamma rays– x-rays & gamma rays

Few molecules in this Few molecules in this layerlayer

Temperature is weirdTemperature is weird

Lapse rateLapse rate

Average temperature decrease in the Average temperature decrease in the troposphere (3.5troposphere (3.5º F/ 1000 feet)º F/ 1000 feet)

Problem: If the surface temp is 40 º F, what is Problem: If the surface temp is 40 º F, what is the temperature at 10,000 feet?the temperature at 10,000 feet?

40°

10,ooo ft

0 ft

answeranswer

55° farentheit° farentheit

Lapse rateLapse rate

If the surface temp. is 25 If the surface temp. is 25 º F, at what º F, at what altitude would it be -10 º F?altitude would it be -10 º F?

10,000 feet10,000 feet