Download 08WGC Chapter 03

Introduction
Section 1:
Earth-Sun Relationships
Section 2:
Factors Affecting Climate
Section 3:
World Climate Patterns
Visual Summary
Climate affects where and
how people live. An
understanding of Earth’s
climates and the factors,
both physical and human,
that influence them adds to
a more complete view of
life on Earth.
Section 1: Earth-Sun
Relationships
The physical
environment affects
people and their
activities. Earth’s position
in relation to the sun
affects temperatures, day
and night, and seasons on
Earth, which in turn
influence when and how
people perform certain
activities.
Section 2: Factors
Affecting Climate
Physical processes
shape Earth’s surface.
Latitude, elevation, wind
patterns, and ocean
currents affect Earth’s
climates.
Section 3:
World Climate Patterns
Geographers organize
Earth into regions that
share common
characteristics.
Geographers classify
Earth’s climate and
vegetation into regions.
Earth-Sun Relationships
Earth’s position in relation to the
sun affects temperatures, day
and night, and seasons on Earth.
Earth-Sun Relationships
• weather
• equinox
• climate
• solstice
• axis
• greenhouse
effect
• temperature
• global
• revolution
warming
Earth-Sun Relationships
• contrast
• affects
• regulated
Earth-Sun Relationships
A. Tropic of Cancer
B. Tropic of Capricorn
Earth-Sun Relationships
The Earth rotates on its
axis, making one
complete rotation every
A. Month
B. 24 hours
C. 365 days
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A. A
B. B
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B
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C
Climate and Weather
The relationship between the Earth and the
sun affects climate, which influences life on
Earth in dramatic ways.
• Earth’s tilt is one reason for variations in sunlight.
• The angle of tilt affects the temperature, which is
measured in Fahrenheit or Celsius.
• Earth rotates on its axis, making one complete
rotation from west to east every 24 hours.
Climate and Weather (cont.)
• While Earth is rotating on its axis, it is also
traveling in an orbit around the sun—this
revolution takes 365 days to complete.
• The Earth’s revolution and tilt cause changes in
the angle and amount of sunlight that reach
different locations on the planet, also known as
seasons.
Effects of Earth’s Tilt
Climate and Weather (cont.)
• The Tropics of Cancer and Capricorn
– When the sun’s rays directly strike the Tropic
of Cancer, this marks the beginning of summer
in the Northern Hemisphere.
– When the sun’s rays directly strike the Tropic
of Capricorn, this marks the beginning of
winter in the Northern Hemisphere.
Climate and Weather (cont.)
• The Poles
– At the North Pole, the sun never sets from
about March 20 to September 23.
– At the South Pole, the sun never sets from
about September 23 to March 20.
The Earth’s Seasons
The imaginary line running from
the North Pole to the South Pole
through the planet’s center is
known as which term?
A. Equator
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A
B
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C
D. Equinox
A
C. Axis
A.
B.
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D.
B
B. Solstice
The Greenhouse Effect
The natural process of the greenhouse
effect has been influenced by human
activity.
• Like the glass in a greenhouse, the atmosphere traps
some heat and keeps it from escaping back into
space too quickly so that the Earth is warm enough to
maintain life.
The Greenhouse Effect (cont.)
• Many scientists claim that in recent decades a
rise in atmospheric carbon dioxide levels has
coincided with a general rise in global
temperatures, also known as global warming.
The Greenhouse Effect
Which of the following do you think has
caused global warming?
A. A natural cycle
B. Human activity
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A
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A
B
C
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C
D. Neither
A.
B.
C.
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D.
B
C. Both
Factors Affecting Climate
Factors such as latitude,
elevation, wind patterns, and
ocean currents affect Earth’s
climates.
Factors Affecting Climate
• prevailing wind • El Niño
• Coriolis effect
• windward
• doldrums
• leeward
• current
• rain shadow
effect
• retains
• creates
• factors
Factors Affecting Climate
A. low latitudes
B. high latitudes
C. Arctic Circle
D. Antarctic
Circle
E. midlatitudes
Factors Affecting Climate
The most variable
weather on Earth is
found in which zone?
0%
A
C. Midlatitude zone
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C
B. High latitude zone
A. A
B. B
C.0%C
B
A. Low latitude zone
Latitude, Elevation, and Climate
Latitude and elevation affect the angle of the
sun’s rays and temperatures on Earth.
• Low latitudes include the Tropic of Capricorn, the
Equator, and the Tropic of Cancer.
• The Earth’s polar areas are considered the high
latitudes.
Latitude, Elevation, and Climate (cont.)
• Midlatitudes:
– Between 30 degrees N and 60 degrees N in
the Northern Hemisphere, and between 30
degrees S and 60 degrees S in the Southern
Hemisphere, are considered the midlatitudes.
– The most variable weather is found here.
Latitude, Elevation, and Climate (cont.)
• Elevation:
– At all latitudes, elevation influences climate
because of the relationship between the
elevation of a place and its temperature.
– As elevation increases, temperature
decreases.
The Influence of Elevation on Temperature
Why does thinner air retain less heat?
A. It is more dense
B. It is less dense
A. A
B. B
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B
A
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Winds and Ocean Currents
Wind and water combine with the effects of
the sun to influence Earth’s weather and
climate.
• Wind Patterns:
– Wind blows because of temperature
differences on Earth’s surface, with tropical air
moving toward the Poles and polar air moving
toward the Equator.
Winds and Ocean Currents (cont.)
– Global winds blow in fairly constant patterns
called prevailing winds.
– The Coriolis effect causes prevailing winds to
blow diagonally rather than along strict northsouth or east-west directions.
World Zones of Latitude and Wind Patterns
Winds and Ocean Currents (cont.)
• The Horse Latitudes:
– When sailors became stranded in the
doldrums, they would lighten the load of the
ships, including livestock, so that a light
breeze could move them.
– These areas then became known as the horse
latitudes.
Winds and Ocean Currents (cont.)
• Ocean currents are caused by factors such as:
– the Earth’s rotation
– changes in air pressure
– differences in water temperature
• The Coriolis effect is observed in ocean currents as
well.
• Ocean currents affect climate in the coastal lands
along which they flow.
World Ocean Currents
Winds and Ocean Currents (cont.)
• Weather and Water Cycle
– Wind and water work together to affect
weather—driven by temperature,
condensation creates precipitation
• El Niño can influence climates around the world.
The Influence of El Niño
A periodic change in the pattern of
ocean currents, water temperatures,
and weather in the mid-Pacific region
is known as which term?
A. Doldrums
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D. El Niño
A
C. Prevailing Winds
A. A
B. B
C.0% C0%
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D. D
B
B. Current
Landforms and Climate
Landforms and bodies of water influence
Earth’s climate patterns.
• The climate of places located at the same latitude
can be very different, depending on the presence or
absence of certain physical features.
• Coastal areas tend to have less changeable weather
than do inland areas.
• Mountain ranges have varying
weather, depending on the area
of the mountain.
The Rain Shadow Effect
Which side of the
mountain is drier than
the other side?
A. Windward
B. Leeward
A. A
B. B
0%
A
0%
B
World Climate Patterns
Geographers classify Earth’s
climate and vegetation into
regions. Recurring climate
phenomena influence climate
patterns.
World Climate Patterns
• natural
vegetation
• mixed forest
• oasis
• permafrost
• coniferous
• deciduous
• widespread
• exceeds
• prairie
• hypothesis
• smog
• consists
World Climate Patterns
A. Tropics
B. Sahara
World Climate Patterns
Which climate would you
prefer to live in?
A. Tropical climate
B. Dry climate
C. Midlatitude climate
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A
A. A
B. B
C.0%C
B
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C
Climate Regions
Geographers divide the Earth into regions
that have similar climates.
• Each of these divisions has its own characteristic
soils and natural vegetation.
Latitude, Climate, and Vegetation
Climate Regions (cont.)
• Climates are organized into five regions:
– Tropical climates—these are found in or near
the low latitudes—the Tropics.
• Tropical wet
• Tropical dry
Climate Regions (cont.)
– Dry climates—there are two types of dry
climates—the desert and the steppe—which
occur in low latitudes or midlatitudes.
– Midlatitude climates—this climate experiences
variable weather patterns and season changes
that give rise to a variety of natural vegetation.
World Climate Regions
Climate Regions (cont.)
• There are four temperate climate regions:
– Marine west coast climate
– Mediterranean
– Humid subtropical
– Humid continental
Climate Regions (cont.)
• High altitude climates—freezing temperatures are
common throughout the year because of the lack
of direct sunlight.
• Three high altitude climate regions are:
– Subarctic
– Tundra
– Ice cap
Climate Regions (cont.)
• Highland climates—high mountain areas, even
along the Equator, share some of the same
characteristics because of the thinning of the
atmosphere at high altitudes.
World Natural Vegetation Regions
Which type of climate is
the least arid?
A. Tundra
B. Desert
C. Rain forest
D. Mixed forest
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A.
B.
C.
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D.
B
A
B
C
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D
C
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D
Climate Changes
Climate changes over time. Although the
causes of change are unclear, evidence
suggests that human activity has influenced
some of the changes.
• Burning fossil fuels releases gases that mix with
water in the air, forming acids that fall in rain and
snow.
• This act can cause many changes in climate.
Climate Changes (cont.)
• Dams and river diversion can also affect climate.
Do you agree that humans are altering
the climate?
A. Strongly agree
B. Somewhat agree
C. Do not agree
0%
A
A. A
B. B
C.0%C
B
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C
Earth-Sun Relationships
•
The relationship of the Earth
to the sun affects climate
patterns around the world.
•
The Earth’s tilt and revolution
cause the seasons by
changing the relationship of
the Earth’s surface to the
sun.
•
When the sun is directly over
the Tropic of Cancer it is
summer in the Northern
Hemisphere. When it is
directly over the Tropic of
Capricorn, it is winter in the
Northern Hemisphere.
Factors Affecting Climate
•
Latitude plays a major role in
climate. The farther one gets
from the Equator, the cooler
the climate.
•
High elevations are generally
cooler than the surrounding
landscape.
•
Other factors that help
determine climate are wind
and water currents, recurring
phenomena such as El Nino,
and large landforms.
World Climate Patterns
•
Geographers divide the world into major climate regions.
•
The major climate regions are tropical, dry, midlatitude, high
latitude and highland climates. Each of these can be broken
down into smaller categories.
•
Each climate region
has its own
characteristic
natural vegetation.
•
Climate patterns
change over time
as a result of both
natural processes
and human activity.
weather
condition of the atmosphere in one
place during a short period of time
climate
weather patterns typical for an area
over a long period of time
axis
an imaginary line that runs through
the center of the Earth between the
North and South Poles
temperature
degree of hotness or coldness
measured on a set scale, such as
Fahrenheit or Celsius
revolution
in astronomy, the Earth’s yearly trip
around the sun, taking 365 ¼ days
equinox
one of two days (about March and
September) on which the sun is
directly above the Equator, making
day and night equal in length
solstice
one of two days (about June and
December) on which the sun’s rays
strike directly on the Tropic of Cancer
or Tropic of Capricorn, marking the
beginning of summer or winter
greenhouse effect
the capacity of certain gases in the
atmosphere to trap heat, thereby
warming the Earth
global warming
gradual warming of the Earth and its
atmosphere that may be caused in
part by pollution and an increase in
the greenhouse effect
prevailing wind
wind in a region that blows in a fairly
constant directional pattern
Coriolis effect
the resulting diagonal movement,
either north or south, of prevailing
winds caused by the Earth’s rotation
doldrums
a frequently windless area near the
Equator
current
cold or warm stream of seawater that
flows in the oceans, generally in a
circular pattern
El Niño
a periodic reversal of the pattern of
ocean currents and water
windward
being in or facing the direction from
which the wind is blowing
leeward
being in or facing the direction toward
which the wind is blowing
rain shadow effect
result of a process by which dry areas
develop on the leeward sides of
mountain ranges
natural vegetation
plant life that grows in a certain area if
people have not changed the natural
environment
oasis
small area in a desert where water
and vegetation are found
coniferous
referring to vegetation having cones
and needle-shaped leaves, including
many evergreens, that keep their
foliage throughout the winter
deciduous
falling off or shed seasonally or
periodically; trees such as oak and
maple which lose their leaves in
autumn
mixed forest
forest with both coniferous and
deciduous trees
prairie
an inland grassland area
permafrost
permanently frozen layer of soil
beneath the surface of the ground
hypothesis
a scientific explanation for an event
smog
haze caused by the interaction of
ultraviolet solar radiation with
chemical fumes from automobile
exhausts and other pollution sources
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