what is wind? horizontal movement of air from an arera of high pressure to an area of low pressure
TRANSCRIPT
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.
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