Earth's Atmosphere Layers and Ocean Circulations: Key Concepts for Environmental Science

Troposphere

Lowest layer; weather; temperature decreases with height.

Stratosphere

Contains ozone layer; temperature increases with height.

Mesosphere

Coldest layer; temperature decreases with height.

Thermosphere

Very hot; absorbs solar radiation; temperature increases with height.

Exosphere

Outermost layer; fades into space.

Ozone: Good vs. Bad

Good Ozone

Located in stratosphere; absorbs harmful UV radiation.

Bad Ozone

Located in troposphere; pollutant causing smog and respiratory irritation.

Ozone Destruction

Caused by CFCs releasing chlorine atoms that break down ozone molecules.

Tilt of Earth

Earth is tilted 23.5°, causing seasons due to changing sunlight angles.

Coriolis Effect

Earth's rotation causes winds and currents to deflect right in the Northern Hemisphere and left in the Southern Hemisphere.

Convection Currents

Warm air rises (less dense), cold air sinks; drives global wind cells; latent heat powers storms.

Hadley Cell

0°-30°; warm air rises at equator, sinks at 30°, causing deserts.

Ferrel Cell

30°-60°; mixing of tropical and polar air; causes variable midlatitude weather.

Polar Cell

60°-90°; cold dense air sinks at poles and moves toward midlatitudes.

Trade Winds

Blow toward equator; curve west.

Westerlies

Blow toward poles; curve east.

Polar Easterlies

Blow from poles; curve west.

Thermohaline Circulation

Global ocean conveyor driven by temperature and salinity; cold salty water sinks, warm fresh water rises.

Melting Ice

Lowers salinity.

Freezing Seawater

Increases salinity.

Evaporation

Increases salinity.

Gyres

Large circular ocean currents driven by wind and Coriolis; clockwise in Northern Hemisphere, counterclockwise in Southern.

El Niño

Weak trade winds; warm water moves east; upwelling stops; Americas get wetter; Australia gets drier.

La Niña

Strong trade winds; increased upwelling; Americas get drier; Australia gets wetter.