CH 16: Earth's Atmosphere

atmosphere

-is a thin layer of gases surrounding
Earth
-contains the oxygen, carbon dioxide, and
water that all life on Earth needs
-keeps temperature stable
-protects living things

water vapor

water in its gaseous form

troposphere

-the atmospheric layer closest to Earth's surface
-temperature decreases as move away from Earth

stratosphere

-the atmospheric layer directly above the troposphere
-bottom half contains most ozone

ozone layer

The area of the stratosphere with a high concentration of ozone

mesosphere

extends from the stratosphere to about 85 km above Earth

thermosphere

can extend to more than 500 km above Earth

ionosphere

region within the mesosphere and thermosphere that contains ions

auroras

displays of colored lights; occur when ions from the Sun strike air molecules, causing them to give off bright colors of light

exosphere

is the atmospheric layer farthest from Earth's surface

gravity

is the force that pulls all objects toward Earth

air pressure

The pressure that a column of air exerts on anything below it

radiation

is the transfer of energy by electromagnetic waves

types of thermal energy transfer

radiation, conduction, and convection

conduction

is the transfer of thermal energy by collisions between particles of matter

convection

The transfer of thermal energy by the movement of matter from one place to another

greenhouse effect

When gases in Earth's atmosphere direct radiation
back toward Earth's surface, this warms Earth's atmosphere more than normal.

wind

is the movement of air from areas of high pressure to areas of low pressure

Coriolis effect

the rotation of Earth causes moving air and water
to appear to move to the right in the northern hemisphere and to the left in the southern hemisphere.

prevailing winds

The difference between high and low
pressure and the Coriolis effect create distinct wind patterns

trade winds

are steady winds that flow from east to west between 30�N latitude and 30�S latitude

doldrums

At about 30�N and 30�S latitude, air cools and sinks creating areas of high pressure and light, calm winds

westerlies

steady winds that flow from west to east between latitudes 30�N and 60�N, and 30�S and 60�S

polar easterlies

cold winds that blow from east to west near the North
Pole and the South Pole.

jet stream

Near the top of the troposphere is a narrow band of high winds

sea breeze

is wind that blows from the sea to the land due to local temperature and pressure differences.

land breeze

is a wind that blows from the land to the sea due to
local temperature and pressure differences.

air pollution

The contamination of air by harmful substances, including gases and smoke