Lesson View
Lesson Factors Affecting
Title: Climate: Global Wind
Systems
World Geography, Module 1, Lesson 4
Summary: World Geography, Module 1, Lesson 4 - Given information about global wind patterns and a variety of
scenarios, students will use maps showing global wind systems to make predictions about paths and affected
areas based upon prevailing wind patterns.
RC/TEKS: RC2; 4.A – The patterns and characteristics of major landforms, climates, and ecosystems of Earth and the
interrelated processes that produce them. SWBT explain how elevation, latitude, wind systems, ocean
currents, position on a continent, and mountain barriers influence temperature, precipitation, and distribution
of climate regions.
Why is Wind Important?
Why is Wind Important?
Definitions:
Easterly Trade Winds (Easterlies)
Winds that prevail in an area extending from the equator to a
latitude of about 30 degrees north or south
Westerly Winds (Westerlies)
Winds that will prevail from 30 degrees to about 60 degrees
Polar Easterlies
Winds dominating the area from 60 degrees to the pole
In this video you will learn why wind is important and what causes global wind systems. View the video and then check your
understanding of the importance of wind by matching the items below.
What are the Global Wind Systems?
What are the Global Wind Systems?
Read the information below to find out some important facts about global wind systems.
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Warm air rises at the equator because it is a low pressure area.
Cold air sinks at the poles because they are high pressure areas.
There are also low pressure areas with sinking air located at about 30 and 60 degrees latitude, north and south.
The earth is divided into three wind circulation systems in the Northern Hemisphere and three in the Southern Hemisphere.
These divisions are based upon the locations of where air rises and sinks. These global wind systems are:
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Tropical Easterlies (also called Trade Winds)
Tropical Easterlies
The dense air that sinks at 30 degrees will
flow back towards the equator and produces
what is known as the tropical easterlies or
trade winds. The trade winds obtained their
name from the sailing ships that transported
goods between Europe and the New World;
these winds helped to propel the ships
toward the Americas.
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Prevailing Westerlies (also called Westerlies)
Prevailing Westerlies
The Prevailing Westerlies are located
between 30 and 60 degrees latitude. In this
zone, the winds blow toward the poles from
the west. Prevailing westerlies in the
Northern Hemisphere are responsible for
many of the weather movements across the
United States and Canada.
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Polar Easterlies
Polar Easterlies
The Polar Easterlies blow from the
northeast to the southwest and is located
between 60 degrees latitude and the poles.
The Polar Easterlies move cold, polar air
from an area of high pressure southward.
Polar fronts are storms that move cold air
from the east.
Check what you have learned about global wind systems by matching the global wind belt with the correct
location on the map.
Which Way Does the Wind Blow?
The following link will open a new window/tab to view a video of children passing a ball back
and forth on a merry-go-round. Once the video concludes, close the window to return to this lesson:
Coriolis, Weather World 2010; University of Illinois WW2010 Project
Think about the following two questions.
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What did you notice about the path of the ball on the merry-go-round?
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Did it appear to travel on a straight path or on a curved path?
Click this link to open a new window/tab to view an animated map showing global wind
circulation.
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Press
in the lower right corner to begin the animation.
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Press
for more information.
When you are finished viewing the animation, close the window to return to this lesson.
Which of the following can you conclude about the patterns of global wind circulation?
A. Winds move in different directions because of gravity
B. Wind direction is affected by the rotation of the earth
C. Winds blow in the same direction in the northern hemisphere
If you chose B - Correct! The rotation of the earth determined the direction of wind belts.
You are the Geographer: Analyzing Global Wind Systems
Do you know how to analyze global wind systems to determine which winds would have helped explorers in the past?
Source: Soffia la quiete, Riccio il colore del Ricardo Inganna,
Flickr
Use what you have learned about global wind systems and the map below to answer the three
questions that follow.
Source: Global wind patterns, NASA
What winds would Columbus have used to travel from Spain (red area on the map) to the Caribbean (yellow area on the
map)?
Polar Easterlies
Prevailing Westerlies
Tropical Easterlies
If you chose Polar Easterlies - Try Again. Notice which wind belts move winds toward the Caribbean.
If you chose Prevailing Westerlies - Try Again. The westerlies would have pushed the ships toward the east.
If you chose Tropical Easterlies - Correct! These winds blew from the east would have pushed ships toward the west.
Which winds would he have needed to return to Spain?
Polar Easterlies
Prevailing Westerlies
Tropical Easterlies
If you chose Polar Easterlies - Try Again. Notice which wind belts move away from the Caribbean.
If you chose Prevailing Westerlies - Correct! The westerlies would have pushed the ships east back toward Europe.
If you chose Tropical Easterlies - Try Again. You are looking for winds that would travel toward Spain.
Would winds have favored European explorers seeking to travel east around the tip of Africa (blue area on the map)?
Yes
No
If you chose Yes - Try Again. Notice how different wind belts would have pushed ships in many different directions.
If you chose No - Correct! The many wind belts that explorers faced would have made travel around the tip of Africa very
lengthy.
Further Exploration
Exploration 1: Do Global Wind systems Influence the Distribution of Climate Regions?
Click the forward arrow in the presentation below to view the information on global wind systems and climate regions.
Do global wind systems influence the distribution of climate regions? From the presentation, you learned that the answer to
that question is YES!
Write a paragraph describing how global wind systems influence the distribution of desert regions.
Exploration 2: Land and Sea Breezes
Land heats and cools more rapidly than the sea. Water takes longer to heat and cool, and holds heat longer than land does.
Because of this, there are temperature differences between the land and the sea, which leads to temperature based wind
circulation.
During the day, the land gets hotter faster, and the hot air rises, creating an area of low pressure. Wind blows from the sea
to the land (sea breeze).
At night, the land cools off faster than the sea. Cooler air descends creating an area of high pressure. Wind blows from the
land to the sea (land breeze).
The following link will launch a new window/tab in which to view an animation of land and sea breezes. When you are
finished viewing the animation, close the window to return to this lesson
Land and Sea Breezes Animation
Explain in your notes why the breeze (in the animation) blew clockwise during the day and counter-clockwise during the
night.
Exploration 3: Movement of Hurricanes
The following link will take you to a website where you will learn more about the movement of hurricanes steered by global
winds. Once you have finished reading the page, close the window to return to this lesson.
Movement of Hurricanes
Answer the following questions in your notes:
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What determines the path of a hurricane?
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Where do most hurricanes originate?
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Which global winds push hurricanes toward the northeast?
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Why do hurricanes dissipate once they move over cold water or large land masses?