Download GLOBAL FORCES NOTES UNIT 9 BACKGROUND INFORMATION

GLOBAL FORCES NOTES
UNIT 9 BACKGROUND INFORMATION
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Global forces are working together to create general patterns of weather phenomenon.
The sun’s energy heats the Earth unevenly. This uneven heating creates a convection
current that generally moves cold air from the poles to the equator.
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However, the rotation of the Earth causes the wind to move in a curved path. This
phenomenon is called the Coriolis Effect. The convection cells and the Coriolis effect
work together to create global winds that blow from the east in the tropics, from the west
in temperate latitudes, and from the east in near the poles. In the United States this
explains why our weather fronts move from the west coast to the east coast and why
hurricanes move toward our southern shores from the east. These relatively constant
winds also influence the movement of ocean water, creating a weather pattern called El
Niňo. In addition to global weather patterns there are some localized events such as
tornadoes and hurricanes.
3 Ways Heat is Transferred
1. Conduction – transfer of heat through
direct contact
(ex. the handle of a metal spoon becomes
hot when placed in a bowl of soup
even though it is not touching the
soup).
2. Convection – the transfer of heat by
the movement of a liquid or gas
(ex. boiling water in a pot, magma in the
earth’s mantle, hot air rises cold air
sinks, wind).
3. Radiation – the transfer of heat
through matter or space (ex. a space
heater warms a room, the sun warms
the earth)
Radiant Energy
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The sun does NOT heat the earth evenly.
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The poles receive less sunlight.
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The equator receives the most direct sunlight.
The Coriolis Effect
Wind and water move in a
curved pattern due to the
rotation of the earth.
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The earth rotates counterclockwise, that is
why water and winds in the northern
hemisphere will move clockwise (west).
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(The windless, rainy zone near the equator is
called the doldrums)
El Nino
An abnormal warming of surface ocean waters in
the eastern tropical Pacific ocean, causing trade
winds to weaken or reverse.
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It is first noticed off the coast of Peru, when
there is a build up of warm water off of S.
America.
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It prevents the upwelling of cold water. When
cold water upwells, it brings nutrients to the
surface, for fish to eat.
Normal
Conditions
La Nina
The winds blowing across the Pacific are stronger
than normal.
El Nino Conditions
Ocean Current
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The steady flow of surface water in a specific
direction.
There are a number of ocean currents found around the Earth. A current is like a vast river within the
ocean, flowing from one place to another. These currents are caused by differences in temperature,
differences in salinity, and by wind. Currents are responsible for a vast amount of movement of the water
found in the Earth’s oceans.
Cli
mat
e
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The weather pattern in a region, over a long period of time.
Weather
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The state of the atmosphere at a specific time
and place.
Air Mass
A large body of air that has properties similar to the
part of Earth’s surface over which it develops.
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(Ex: An air mass that develops over the
tropics will be warmer than one that
develops at the poles.)
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Air masses will move from the poles down
to the equator, because cold air is more
dense, and sinks. Warm air is less dense.
The warmer it is, the quicker it will rise.
Fronts
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A boundary between 2 air masses that have
different densities, moisture, or temperatures.
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Cold front – cold air moves underneath warm
air suddenly. Extreme temp. differences will
cause large thunderstorms or tornadoes to form.
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Warm front – Warm air skims over colder air.
Leads to wet weather.
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Occluded front – Involves 3 air masses of different temps.
Ex. Cold air moves into warm air with cold air on the other
side of it. C-W-C
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Stationary front – When a boundary between air masses
stops moving. May stay in the same place for several
days, bringing wind and rain.
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A large, swirling, low pressure system that forms over
the warm Atlantic ocean. (pg. 474)
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Turns heat energy into wind
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Most powerful storm
Hurricanes
Tornado
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A violent, whirling wind that
moves in a narrow path over land.
Fujita Scale (Tornadoes)
A large, swirling, low pressure
system that forms over the warm
Atlantic ocean. Turns heat energy
into wind. Most powerful storm.