The Greenhouse EffectThe Greenhouse Effect

Process by which the atmosphere traps Process by which the atmosphere traps infrared rays over the earth’s surface.infrared rays over the earth’s surface.

The Ozone LayerThe Ozone Layer

A layer of ozone (OA layer of ozone (O33) in the stratosphere ) in the stratosphere

that blocks out the sun’s deadly ultraviolet that blocks out the sun’s deadly ultraviolet rays acting as our planet’s natural sunblock. rays acting as our planet’s natural sunblock.

Global WarmingGlobal Warming

Refers to an average Refers to an average increase in the Earth's increase in the Earth's temperature, which in turn temperature, which in turn causes changes in climate. causes changes in climate. A warmer Earth may lead A warmer Earth may lead to:to:– Changes in rainfall patterns.Changes in rainfall patterns.– A rise in sea level.A rise in sea level.– A wide range of impacts on A wide range of impacts on

plants, wildlife, and humans.plants, wildlife, and humans.

Atmospheric PressureAtmospheric Pressure

The force of air The force of air pressing down on the pressing down on the earth’s surface.earth’s surface.

Presses down on Presses down on every surface from all every surface from all directions with a force directions with a force of 15 lb/inof 15 lb/in22..– An instrument that An instrument that

measures atmospheric measures atmospheric pressure is called a pressure is called a barometerbarometer..

Low PressureLow Pressure

Large parcels or pockets of uncompressed airLarge parcels or pockets of uncompressed air Warmer airWarmer air Air is “spread out” so fewer air particles push on Air is “spread out” so fewer air particles push on

any given area with less pressureany given area with less pressure Low density = air molecules spread outLow density = air molecules spread out Rising air that circulates in a counterclockwise Rising air that circulates in a counterclockwise

direction in the Northern Hemispheredirection in the Northern Hemisphere Called Called CyclonesCyclones

High PressureHigh Pressure

Large parcels or pockets of compressed airLarge parcels or pockets of compressed air Colder airColder air More air particles pressing on a given surface areaMore air particles pressing on a given surface area High density = air molecules packed togetherHigh density = air molecules packed together Falling air that circulates in a clockwise direction in Falling air that circulates in a clockwise direction in

the Northern Hemispherethe Northern Hemisphere Called Anticyclones Called Anticyclones H

WindWind

What causes the wind?What causes the wind?– Differences in air Differences in air

pressure: High pressure: High Low Low Two main wind patternsTwo main wind patterns

– GlobalGlobal– locallocal

Does the wind move Does the wind move straight up and down?straight up and down?– Coriolis EffectCoriolis Effect

High Pressure

High Pressure

Low Pressure

Convection

Convection

The Coriolis EffectThe Coriolis Effect

Coriolis CannonballCoriolis Cannonball

Coriolis Coriolis EffectEffect

Circulation of air is affected by the earth’s rotationCirculation of air is affected by the earth’s rotation– Coriolis EffectCoriolis Effect – deflection of a fluid because of Earth’s rotation – deflection of a fluid because of Earth’s rotation

Deflects air in the Northern Hemisphere to the rightDeflects air in the Northern Hemisphere to the right Deflects air in the Southern Hemisphere to the leftDeflects air in the Southern Hemisphere to the left

Air moves from high to low pressure

Global WindsGlobal Winds

Trade WindsTrade Winds

WesterliesWesterlies

Polar EasterliesPolar Easterlies

• Each hemisphere has Each hemisphere has three main wind belts or three main wind belts or prevailing winds (areas prevailing winds (areas of similar wind patterns)of similar wind patterns)

Doldrums and Horse LatitudesDoldrums and Horse Latitudes Areas of weak and slow moving air Areas of weak and slow moving air

Air moves from high to low pressure

Jet StreamJet Stream

Narrow bands of high speed winds that blow Narrow bands of high speed winds that blow in the upper troposphere and lower in the upper troposphere and lower stratosphere are stratosphere are jet streasjet streas..

BreezesBreezes

Land BreezeLand Breeze– When wind moves from high pressure (over When wind moves from high pressure (over

land) to low pressure (over water).land) to low pressure (over water).– Usually occurs at night.Usually occurs at night.

Sea/Lake BreezeSea/Lake Breeze– When wind moves from high pressure (over When wind moves from high pressure (over

water) to low pressure (over land).water) to low pressure (over land).– Usually occurs during the day.Usually occurs during the day.

Local WindsLocal Winds