Transcript Chapter 3: Climates of the Earth

Introduction
Section 1:
Earth-Sun Relationships
Section 2:
Factors Affecting Climate
Section 3:
World Climate Patterns
Summary
Geographers study how
people, places, and
environments are
distributed on Earth’s
surface.
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
Relationship
How does Earth’s
position in relationship
to the sun affect life on
Earth?
Earth-Sun Relationships
• weather
• climate
• equinox
• axis
• greenhouse effect
• temperature
• global warming
• revolution
• solstice
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.
Earth-Sun Relationships
A. Tropic of Cancer
B. Tropic of Capricorn
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
B. Solstice
C. Axis
D. Equinox
A.
B.
C.
D.
A
B
C
D
The imaginary line running from the
North Pole to the South Pole through the
planet’s center is known as which term?
A. Equator
B. Solstice
C. Axis
D. Equinox
A.
B.
C.
D.
A
B
C
D
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
Section 2: Factors
Affecting Climate
What factors can
affect how
climates are
distributed on
Earth’s surface?
Factors Affecting Climate
• prevailing
wind
• Coriolis
effect
• El Niño
• doldrums
• rain shadow
effect
• current
• windward
• leeward
Factors Affecting Climate
A. low latitudes
B. high latitudes
C. Arctic Circle
D. Antarctic
Circle
E. midlatitudes
Factors Affecting Climate
Where is the most variable weather on
Earth is found in which zone?
A. Low latitude zone
B. High latitude zone
C. Midlatitude zone
A. A
B. B
C. C
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. A
B. B
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 north-south
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
B. Current
C. Prevailing Winds
D. El Niño
A.
B.
C.
D.
A
B
C
D
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
The Rain Shadow Effect
of the mountain.
Section 3: World Climate Patterns
How do geographers classify
Earth’s climate and
vegetation?
World Climate Patterns
• natural
vegetation
• oasis
• mixed
forest
• coniferous
• permafrost
• deciduous
• hypothesis
• prairie
• smog
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
A. A
B. B
C. 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
A.
B.
C.
D.
A
B
C
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.
• Dams and river diversion can also affect
climate.
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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