In this lesson, students will observe
a variety of computer models showing wind, cloud, and pollution
movements over the globe. Students will use this information
to as an introduction to determining the three-cell model
of weather and give names to the Hadley, Ferrell, and Polar
Cells. They will also uncover the Trade winds, Westerlies,
and Polar winds.
Purpose – Exploration of world wind patterns.
will be able to:
1. Recognize that global winds move in specific directions in specific latitudes
and describe that in a written form.
2. Relate the motion of the wind belts to historical navigation.
D: Earth and Space Science
ENERGY IN THE EARTH SYSTEM
• Earth systems have internal and external sources of energy, both of which
create heat. The sun is the major external source of energy. Two primary sources
of internal energy are the decay of radioactive isotopes and the gravitational
energy from the earth’s original formation.
• Heating of earth’s surface and atmosphere by the sun drives convection
within the atmosphere and oceans, producing winds and ocean currents.
• Global climate is determined by energy transfer from the sun at and near
the earth’s surface. This energy transfer is influenced by dynamic processes
such as cloud cover and the earth’s rotation, and static conditions such
as the position of mountain ranges and oceans.
• Movement of matter between reservoirs is driven by the earth’s
internal and external sources of energy. These movements are often accompanied
by a change in the physical and chemical properties of the matter. Carbon, for
example, occurs in carbonate rocks such as limestone, in the atmosphere as carbon
dioxide gas, in water as dissolved carbon dioxide, and in all organisms as complex
molecules that control the chemistry of life.
The sun is the driving force
behind the global wind patterns. As the sun heats the
equator, the air
heated and rises, moving North and South, away from
the equator. Cold air rushes in to take its’ place.
This creates a convection cell that extends from the
equator to about 30 degrees North and South Latitude.
This cell is called the Hadley cell after it discoverer
George Hadley in 1735. The next cell is the Ferrell
cell, which was identified by the American William
Ferrell in the 1800s. This cell connects the sinking
air at the 30th parallels to the Westerlies. It was
Ferrell who noted that the currents in the Westerlies
tend to give rise to cyclonic action as a result of
winds moving around a spinning Earth. The Ferrell Cells
sink at the 30th parallels and rise again at the 60th
parallels where the Polar Cells begin.
More detailed information available from
Climate Change -
More great information is available at USA Today Weather
Basics - (http://www.usatoday.com/weather/resources/basics/wworks0.htm)
and Resource Web sites
(Shows Global Air Currents – good
views of Trades and Westerlies)
Global Water Vapor Animation
(Shows Motion of Vapor in
the Atmosphere - good views of Trades and Westerlies)
Earth Probe TOMS Aerosol Index (Shows Trades and southern
Westerlies nicely, you need to cut and paste this address
into the web to get it to show the animation.)
Meteosat Infrared Satellite Data from NASA
Global Composite Satellite Data from NASA
Global Composite Water Vapor Satellite Data
North America Infrared Satellite Data
(menu screen here provide access to above maps - good
Trades and Westerlies – set
the image loop as high as possible so the students get
the most time possible to observe wind motion)
Animated Global IR