The atmosphere- Layer that surrounds earth, that is constantly changing. (pg.4)

Composition of Earths Atmosphere

•Earth Has 4 Main Systems that Interact

• Troposphere• Contains Most Clouds and

Weather• Temperature cools are you go

higher, 50% of sun’s energy passes through, and 50% is reflected back

• Most of the Troposphere’s heat is from earth (convection)

Composition of Earths Atmosphere

•Earth Has 4 Main Systems that Interact

• Stratosphere• Contains ozone that

absorbs most of the sun’s ultraviolet radiation (pg. 7)

• Gets warmer as you go up

Composition of Earths Atmosphere

•Earth Has 4 Main Systems that Interact

• Mesosphere• The coldest part of the atmosphere, temperatures can reach -93 degrees Celsius

Composition of Earths Atmosphere

•Earth Has 4 Main Systems that Interact

• Thermosphere• Temperatures reach

1,700 degrees Celsius• Filters out X-rays, and

Gamma Rays from the sun

IonosphereIs located in the upper

part of the mesosphere and lower part of the thermosphere

Particles can be electrically charged in the atmosphere called ions, at times these ions can radiate light of different colors

Composition of Earths Atmosphere

Altitude

The higher the altitude, the lower the air pressure.

The lower the altitude, the higher the air pressure.

Temperature

As the temperature goes up, the air pressure goes down. (hot molecules are further apart- less pressure).

As the temperature goes down, the air pressure goes up. ( cold air is more dense than warm air).

Heating of the Atmosphere

Conduction Transfer of heat through matter by

molecular activity Energy of molecules is transferred through

collisions from one molecule to another, heat flowing from high to low temp.

Metals are good conductors Air is a very poor conductor of heat Conduction is the least significant of the

three as a means of heat transfer for the atmosphere

Convection Most of the heat transport that occurs in

the atmosphere is carried on by convection.

Def: The transfer of heat by mass movement or circulation within a substanceTakes place in fluids (oceans, air) where atoms

and molecules are free to move about Pan example:

Warmer water rises, cooler water sinksUneven heating of water, from the bottom upWater will continue to “turn over”, producing a

convective circulation

Radiation

Travels in all directions from its source Travels through the vacuum of space,

does not need medium like the other two Radiation is the heat-transfer

mechanism by which solar energy reaches our planet

Greenhouse effect Approx. 50% of the solar energy that strikes the

top of the atmosphere reaches Earth’s surface and is absorbed

Most of this energy is then reradiated skyward The radiation that it emits has longer wavelengths than

solar radiation (terrestrial radiation) The atmosphere is an efficient absorber of this type of

radiation (85% absorbed) Water vapor and CO2 are the principal absorbing gases The absorbed terrestrial radiation is then reradiated back

to Earth Atmosphere acts like a real Greenhouse (with windows

open)

Global Warming Carbon dioxide in the atmosphere absorbs some

of the radiation emitted by Earth and thus contributes to the greenhouse effect

Changes in content of CO2 could influence air temperature

Rapid growth of industrialization, burning of fossil fuels has added vast quantities of CO2 to the atmosphere

The clearing of forests also contributes substantially. Carbon dioxide is released as vegetation is burned or decays

Consequences of Global Warming? Probable rise in sea level? Shifts in the paths of large-scale storms, affecting

the distribution of precipitation and the occurrence of severe weather

Stronger tropical storms Increases in the frequency and intensity of heat

waves and droughts Gradual environmental shift, imperceptible to

public. Nevertheless will have a strong impact on future economics and thus leading to social and political consequences.

Wind

Wind moves from high areas of pressure to low areas of pressure

Moves from West to East across the U.S.

Actual wind which blows, as diverted by Coriolis Force

CORIOLIS FORCE

High

Low

� Pressure gradient wind blows from high pressure towards low pressure.� The earth’s rotation diverts this wind direction laterally. This force is called the CORIOLIS FORCE.� The Coriolis force diverts wind the right in the northern hemisphere; to the left in the south.

PRESSURE BELTSRising air at the equator causes the equatorial belt of low pressure

Descending air at about 30ºN and 30ºS causes the sub-tropical belt of high pressure

Rising air at about 60ºN and 60ºS causes a mid-latitude belt of low pressure

Descending air at the poles causes the polar high pressure areas

Mid latitude low pressure

Mid latitude low pressure

Equatorial low pressure

Sub-tropical high pressure

Sub-tropical high pressure

Polar high pressure

Polar high pressure

Different Winds

Trade WindsThese are in both hemispheres and blow from

30 degrees latitude to the equator. (pg. 16) Westerlies

Wind belts found in both north and south hemispheres between 30 and 60 degrees latitude. They flow towards the poles in opposite directions of the trade winds. (pg. 17)

Different Winds

Polar EasterliesThey extend from the poles to the 60 degree

latitude in both hemispheres. (pg. 17) Jet Streams

High speed narrow belts that blow in the upper troposphere and lower stratosphere.

Speeds can reach up to about 310 mph. Local Winds

Are influenced by the geography of an area. (pg. 18)

Types of Air Pollution

Pollutants

Primary Pollutants are put here on earth by human or natural activity.Exhaust, ash from volcanic eruptions, soot

from smoke stacks. Secondary Pollutants are formed from

chemical reactions.Many secondary pollutants are formed when

a primary pollutant reacts with sunlight○ Acid Raid, Smog

Have Regulations Helped? In 1997, the emissions of the five major

primary pollutants in the United States were about 31 percent lower than 1970.

In 1990, Congress passed the Clean Air Act Amendments, which further tightened controls on air quality.

Regulations and standards regarding the provisions of the Clean Air Act Amendments of 1990 are periodically established and revised.