• LEARNING TARGETS: LOCAL AND GLOBAL WIND

Wind

The horizontal movement of air due to...1. Temperature Differences2. Pressure Differences

Warm airrises andcold airsinks.TemperatureDifferences

High and lowpressure liketo balanceout.PressureDifferences

The cooler air movesinto to take the placeof warmer air.

The cooler air movesinto to take the placeof warmer air.

More DenseMore Dense

Higher Air PressureHigher Air Pressure

Molecules moveslower and get closertogether.

Molecules moveslower and get closertogether.

Colder Air SinksColder Air SinksLess DenseLess Dense

Molecules move Fasterand get farther apart.Molecules move Fasterand get farther apart.

Warmer Air RisesWarmer Air Rises

Less Air PressureLess Air Pressure

WINDS ARE NAMED FROM WHERE THEY COME FROM!

1. Temperature difference = rising/sinking air.2. Rising/sinking air = pressure difference.

3. Pressure likes to balance out = WIND !!!

SEA BREEZE Mountain BREEZE PrevailingWesterlies

NE TradeWinds

PolarEasterliesLand BREEZE Valley BREEZE

LOCALIZED WINDSLOCALIZED WINDS GLOBAL WINDSGLOBAL WINDS

Wind Trends

• Air Rises

Low Pressure

• Air Sinks

HighPressure

Pressure• Always flows from a higher pressure to a lower

pressure.

Wind Trends

Always flows from a colder temperature to a warmertemperature

TEMPERATURE

Where does this occur?

Wind current on a…1. global scale.2. Local scale

Sea Breeze

• Daytime• Land heats faster than water

throughout the day.• Air Above Land is warmer than air

above water• Colder – Higher Pressure air

displaces warmer – Lower Pressureair over land.

• Breeze is felt off body of water.

Land Breeze

• Night• Land looses heat quicker than water

at night.• Air above land is cooler than air

above water.• Colder – Higher Pressure over land

displaces warmer – Lower Pressureover water.

• Breeze is felt from off land.

Sea Breeze

Wind blows from Sea to Land.

Land Breeze

Wind blows from Land to Sea.

Valley Breeze

• Daytime• The shape of the land heats valley

faster than sides of Mountain dueto the striking angle of the sun.

• The colder air – High pressure justabove valley floor displaceswarmer air (Lower Pressure)making the warmer air rise up thesides of the mountain.

• Breeze is felt coming up theMountain.

Mountain Breeze

• Night• The shape of the land develops this

breeze.• Air cools off during the night inside

and down the mountain.• Colder (H) displaces the warmer (L)

air allowing the warmer air to riseinside the center of the valley.

• Breeze is felt coming downmountain.

Global Temperature Patterns

• Wind currents thatdevelop on a GLOBALSCALE

• Still a result oftemperature andpressure differences.

Global Winds

HadleyCells. • Air moves

between thewarm equatorand the coldpoles.

GlobalWinds

Global Temperature Patterns

The sun’s rays are stronger nearthe equator causing morewarming. The air here is warm.

The sun’s rays are weakernear the equator causing lesswarming. The air here is cool.

So Air tries to move between the poles from a high to low pressure = Global Winds

The Coriolis Effect

• Air does notmove in astraight linebecause ofEarth’s rotation.

CoriolisEffect

Earth spin makes the wind curveinstead of traveling in a straight line.

Curve to the RIGHT in theNORTHERN HEMISPHERE.

Curve to the LEFT in theSOUTHERN HEMISPHERE.

Global Winds

LOW PRESSURE

HIGH PRESSURE LOW PRESSURE

HIGH PRESSURE

LOW PRESSURE

HIGH PRESSURE LOW PRESSURE

HIGH PRESSURE

NorthernHemisphere

SouthernHemisphere

Global Winds

60°S

30°S

0°

30°N

60°N

Prevailing Westerlies- From 30°N to60°N- Deflected to right

Easterly Trade Winds- From 30°N to O°- Deflected to right

Polar Easterlies- From 90°N to60°N- Deflected to right

Polar Easterlies- From 90°N to60°N- Deflected to right

Easterly Trade Winds- From 30°S to 0°- Deflected to left

Prevailing Westerlies- From 30°S to60°S- Deflected to left

Polar Easterlies- From 90°S to60°S- Deflected to left

Doldrums

Remember, winds arenamed from wherethey come.