Global Winds
Chapter 15.3
A. Global Winds and Local Winds
What causes wind?
1. Wind is caused by the movement of air which
is caused by differences in air pressure.
Differences in air pressure are caused by the
uneven heating and cooling of the Earth.
2. Warm air is less dense and creates an area of
low pressure
3. Cold air is more dense and creates an area of
high pressure.

GLOBAL WINDS
Patterns of air circulation
90*
Polar Easterlies
60*
Westerlies
30*
Trade WInds
0*
30*
60*
90*

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Questions
What winds would Columbus have used
to travel from Spain to the Caribbean?
Which winds would he have needed to
return to Europe?
Would winds have favored European
explorers seeking to travel east around
the tip of Africa?
Trade winds
US
Eur.
Prevailing Westerlies
No
B. POLAR EASTERLIES
GLOBAL WIND
1. Extend from the North and South Poles
poles to 60 degrees latitude.
2. Polar easterlies carry cold arctic air
C. WESTERLIES- GLOBAL WIND
1. These wind belts lie
between 30 and 60
degrees latitude.
2. Westerlies flow
toward the poles
from west to east.
3. Affects the weather
in the United States.
D. TRADE WINDS
1. Winds that blow from 30 degrees
latitude almost to the equator, 0
degrees latitude.
2. Winds are named for the fact that
these winds moved sailors across the
Atlantic Ocean from Europe to the
Americas.
3. Northeast Trade Winds blow from
30* North toward the equator, 0*
4. Southeast Trade Winds blow from
30* South toward the equator, 0*
E. DOLDRUMS- GLOBAL WIND
The trade winds meet at an area called the doldrums.
1. This area is located around the equator, 0 degrees
latitude.
2. This is an area of low pressure where there is very
little wind.

F. HORSE LATITUDES-GLOBAL WIND
1. Located at 30 degrees
north and 30 degrees south
latitude.
2. An area of little wind.
 Name given by sailors who
got stuck here because of
lack of wind, travel time
was slow.
 Horses were thrown
overboard to save water
for sailors.
G. THE CORIOLIS EFFECT
1. The curving of winds due to the Earth’s
rotation is called the Coriolis Effect.
2. Because of the Coriolis Effect winds curve to
the east and west.
 Winds traveling north curve to the right, or
east.
 Winds traveling south curve to the left or west.
H. THE JET STREAM
1. The jet streams are narrow belts of
high-speed winds that blow in the
upper troposphere and lower
stratosphere.
2. Unlike global winds, jet streams do
not follow regular paths.
3. Knowing the path of the jet stream
can help airplane pilots travel faster
as they ride the jet stream.
4. Meteorologists can track a storm if
they know the location of the jet
stream.
I. Local Winds
1. Move short distances and blow from any direction.
 Geographic features, a shoreline or a mountain can
produce temperature differences.
2. Sea breeze
3. Land breeze
 www.classzone.com/books/earth_science/terc/content
/visualizations/es1903/es1903page01.cfm?chapter_no
=19
3. Mountain Breeze
4. Valley Breeze
J. SEA BREEZE- LOCAL WIND
During the day air over ocean is cooler and
forms high pressure.
 Warm air over land, low pressure.
 Cool air moves inland and overtakes area of
warm air.
 Cool air has higher pressure than warm air.
1. Wind moves from sea toward land.

K. LAND BREEZE- LOCAL WIND
At night air over ocean is warmer,
warm air rises and creates low
pressure.
 Air over land is cooler and creates high
pressure.
 Cool air moves toward ocean causing a
land breeze.
1. Wind moves from land toward sea.

Sea Breeze and Land Breeze
Animation

http://www.classzone.com/books/earth_scienc/
terc/content/visualizations/es1903/es1903page
01.cfm?chapter_no=19local breeze
L. MOUNTAIN BREEZE
LOCAL WIND
At night mountains cool
faster than valley.
 Cool air moves downward
and creates a mountain
breeze.
1. Mountain breeze moves
down.
2. Cold air sinks.
3. Cold air / High pressure

M. VALLEY BREEZE
LOCAL WIND
Sun warms the valley and the air above it.
 Warm air rises and moves up mountain
causing a valley breeze.
1. Valley breeze moves up.
2. Warm air rises.
3. Warm air /low pressure

N. High Pressure and Low Pressure
1. Low Pressure / Warm
Air
2. Cloudy weather
occurs with low
pressure.
3. High Pressure / Cold
Air
4. Clear weather occurs
with high pressure
Quiz
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Which type of breeze occurs when cool air moves from water toward
land?
Which type of breeze occurs when cool air moves from land toward
water?
What is the area of low pressure around the equator called? There is low
pressure and little wind here.
High speed winds that occur in the upper troposphere and lower
stratosphere?
Winds in the North curve to the right, or east, and winds in the south
curve to the left, or west. This is known as….
Which wind belt affects most of the United States? They blow from 30*
to 60* north and south.
Cloudy weather occurs with……………pressure.
Clear weather occurs with………………pressure.
These winds blow from any direction and move short distances.
Cold winds that blow from the poles to 60* latitude are called…..
These winds are located at 30* N and 30* south latitude.
These winds blow from 30* North and 30* South toward the equator.
This local wind is caused by cool air moving down the side of a
mountain
This local wind is caused by warm air moving up from a valley.
Answers
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Sea breeze
Land breeze
Doldrums
Jet stream
Coriolis effect
Westerlies
Low pressure
High pressure
Local winds
Polar easterlies
Horse latitudes
Trade winds
Mountain breeze
Valley breeze