Download What are “GLOBAL WINDS”?

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?
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
SEA
BREEZE
LAND
BREEZE
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 BREEZE
a)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
GLOBAL WINDS
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 ENERGY
Because 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
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