Download Global Systems Lesson04 Global Wind Patterns

Lesson 4: Distributing Solar Energy
Key Points:
1. Understand how energy is
distributed on earth.
2. Understand the role the
winds play in distributing
energy.
3. Know what the Coriolis effect
is and how it distributes
energy.
4. Recognize global wind
patterns as a product of
convection and the earth’s
rotation.
Distributing the Earth’s Energy Budget
 The earth’s atmosphere is in perpetual motion, movement that is
striving to eradicate the constant differences in pressure and
temperature between different parts of the globe.
Distributing the Earth’s Energy Budget
 Nature does not like imbalance or inequity. Variations in
temperature create variations in pressure – as a result air moves
from areas of high pressure to low to restore the balance. We sense
this movement as wind.
Distributing the Earth’s Energy Budget
 The wind in turn transports
heat energy and moisture,
influencing the global
climate. The jet stream is
a major wind mechanism,
created by the differences
in temperature between
the polar and tropical
regions.
Global Wind Patterns
 Prevailing winds in an area
tend to come from the
same direction and are
influenced by the rotation
of the earth and
convection currents.
 Near the equator hot air is
always rising and is carried
northward to cooler areas
as it cools it descends
(creating a convection
current) and then returns
to the equator.
Global Wind Patterns
 On its way there however the
motion of the earth deflects it
causing the prevailing winds we
are familiar with. (If these winds
did not occur, the earth would
not be able to transfer energy
and the equator would become
too hot and the poles even
colder.)
 This causes the wind patterns
we see on earth, easterly trades
near the equator, and westerlies
in the temperate zones.
Jupiter Also Shows this patterns very well.
The Coriolis Effect
 The difference in solar radiation budgets between the poles and the equator
tends to cause air to move directly north and south. However, since the earth is
rotating, the winds are deflected either to the left or the right. The Coriolis Effect
is the deflection of any object from a straight line path by the rotation of the earth.
Thus winds in the north are deflected right and winds in the southern hemisphere
to the left.
Questions For Review
1.
2.
3.
4.
Describe the effect of unequal distribution of thermal
energy on earth on the temperature of the atmosphere.
Explain how the Coriolis effect influences the direction
of winds in the northern hemisphere.
What are the trade winds and where do they occur?
What are jet streams?