What is wind?

HORIZONTAL MOVEMENT OF AIR FROM AN ARERA OF

HIGH PRESSURE TO AN AREA OF LOW

PRESSURE

What causes wind?

DIFFERENCES IN AIR

PRESSURE

                             

                               

                                   

How do scientists measure wind

speed?

ANEMOMETE

R

SCIENCE ALERT

HEAT IS ALWAYS TRANSFERRED FROM WARMER

OBJECTS TO COOLER OBJECTS

What is “WIND CHILL FACTOR”?

Wind blowing over

your body and

removing heat.

I. WHAT IS WIND?

a) Horizontal movement of air from an area of high pressure to an area of low pressure.

b) Wind speed is measured with an ANEMOMETER

c) WIND CHILL FACTOR is the amount of heat being removed from your body as cold wind blows over your body.

SCIENCE ALERT

WARMER AIR IS LESS DENSE THAN COOLER AIR

“Cold air follows the warm air”

LOCAL WINDS

Blow over short distances

Caused by unequal heating of the Earth’s

surface within a small area

LOCAL WINDS

SEABREEZE

LANDBREEZE

SEA BREEZE – winds coming from a body of water

LAND BREEZE – winds coming from a land mass

II. Local Winds

a) Caused by unequal heating of the Earth’s surface within a small area for a short distance

b) SEA BREEZEa)Takes more energy to heat up a body of

water than it does land. b)Cooler air from a body of water takes the

place of warm air over land

c) LAND BREEZE• Cooler air from a land mass takes the

place of the warm air over the water

GLO

BA

L W

IND

S

What are “GLOBAL WINDS”?

Like local winds, they are caused by

unequal heating of the earths surface but occurs over a larger

area.

How is the SUNS energy distributed over the EARTHS surface?

AREA OF MOST DIRECT ENERGY

AREA OF LEAST DIRECT ENERGYBecause of the curvature of the EARTH, the SUN’S energy is spread out over a larger area …

…as a result, it’s cooler at the POLES than it is at the EQUATOR

What are “GLOBAL CONVECTION CURRENTS”?Temperature

differences between the EQUATOR and the POLES produce giant convection currents.

What is the “CORIOLIS EFFECT”?

The way the Earth's rotation makes global

winds curve

WIN

D PATH

WIN

D P

ATH

If we had no EARTH rotation…

…but because the EARTH rotates counter-clockwise…

…the actual wind path is…

III. Global Winds

a) Like local winds, global winds are caused by unequal heating of the earths surface but occurs over a larger area.

b) Temperature differences between the EQUATOR and the POLES produce global convection currents.

c) Coriolis Effect is the way the Earth's rotation makes global winds curve.

What are the GLOBAL WIND BELTS?

Belts of winds and calm areas that circle

the EARTH

The CORIOLIS EFFECT produces calm areas…

DOLDRUMS•Regions near the EQUATOR with little or no winds.

•Warm air rises steadily, creating an area of low pressure.

•Cool air moves in but is heated before it moves far.

HORSE LATITUDES•At about 30º north and south

latitudes the warm air stops moving towards the poles and sinks creating another belt of calm air.

•Named because ships in this area could not move because of a lack of winds. Sailors running out of food and water would throw their horses overboard.

HORSE LATITUDES

What are the major GLOBAL WIND

BELTS?

•Trade Winds•Polar Easterlies•Prevailing Westerlies

The CORIOLIS EFFECT produces wind belts…

TRADE WINDS

•As the warm air sinks into the HORSE LATITUDES it produces a high pressure that causes surface winds to blow towards the equator.

•The CORIOLIS EFFECT allows the winds to move towards the west.

TRADE WINDS

PREVAILING WESTERLIES

•Located between 30º to 60º latitudes north and south winds blow towards the poles are turned towards the east by the CORIOLIS EFFECT.

PREVAILING WESTERLIES

POLAR EASTERLIES•Cold air near the poles sink and flow back towards the lower latitudes.

•The COLIOLIS EFFECT shifts these winds back to the west.

POLAR EASTERLIES

JET STREAMS

•Bands of high speed winds (200 to 400 Kph)

•Located 10 km above the Earth’s surface

•Blow west to east

•Caused by the meeting of different air temperature masses

IV. Global Wind Belts

a) Belts of winds and calm areas that circle the EARTH

b) DOLDRUMS

– Regions near the EQUATOR with little or no winds.

– Warm air rises steadily, creating an area of low pressure.

– Cool air moves in but is heated before it moves far.

c) HORSE LATITUDES

a) At about 30º north and south latitudes the warm air stops moving towards the poles and sinks creating another belt of calm air.

b) Named because ships in this area could not move because of a lack of winds. Sailors running out of food and water would throw their horses overboard.

d) Trade winds

a) As the warm air sinks into the HORSE LATITUDES it produces a high pressure that causes surface winds to blow towards the equator.

b) The CORIOLIS EFFECT allows the winds to move towards the west.

e) Prevailing Westerlies

a) Located between 30º to 60º latitudes north and south winds blow towards the poles are turned towards the east by the CORIOLIS EFFECT.

f) Polar Easterlies

a)Cold air near the poles sink and flow back towards the lower latitudes.

b)The COLIOLIS EFFECT shifts these winds back to the west.

g) Jet Stream

a) Bands of high speed winds (200 to 400 Kph)

b) Located 10 km above the Earth’s surface

c) Blow west to east

d) Caused by the meeting of different air temperature masses