Transcript geo ch 3 climates of the earth

Climate &
Vegetation
Chapter 3
Earth-Sun Relationships
• Axis – imaginary line that run through
the center of the Earth
• Earth’s axis is tilted 23 ½ °
• Earth’s tilt affects the climate since all
places do not receive the same amount
of direct sunlight.
Earth-Sun Relationships
• Revolution – orbit around the sun
• Earth’s revolution takes 365 ¼ days.
• Revolution causes the changing
seasons.
Earth-Sun Relationships
• Rotation – spinning on its axis
• The Earth’s rotation takes 24 hours.
• Rotation causes day and night.
Earth-Sun Relationships
• Equinox – either of the 2 times each year
(spring and fall) when day and night are of
nearly equal length everywhere on Earth
• Solstice – either of the 2 times a year
(summer and winter) when the sun appears
directly overhead at noon to observers at the
Tropics of Cancer and Capricorn
Weather vs. Climate
• Weather - condition of the atmosphere
at a particular location and time.
• Climate – the term for weather
conditions at a particular location over a
long period of time
Weather Extremes
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Hurricanes
Tornadoes
Blizzards
Droughts
Floods
Factors that Affect Climate
Latitude – the amount of direct sunlight
affects climate
• Places closer to the Equator receive
more direct sunlight than areas closer to
the poles which receive slanted rays.
Factors that Affect Climate
Landforms – mountains can block
precipitation which can affect climate. This is
called the orographic effect (rain shadow).
• Ex. - Sierra Nevada range and the Mojave
Desert
• Windward side – wet
• Leeward side - dry
Factors that Affect Climate
Wind currents
• Prevailing winds are winds that blow in
a fairly constant pattern.
• The direction of the winds can
determine what type of weather patterns
an area will see.
Factors that Affect Climate
Ocean currents – cold and warm “rivers”
of water known as currents, flow in the ocean
• Cold currents cool the lands they pass while
warm currents have a warming effect.
• Ex. North Atlantic Drift flows near western
Europe and gives the area a mild climate
despite its northerly latitude
North Atlantic Drift
Factors that Affect Climate
Proximity to large bodies of water
• Water is slower to heat and cool than land.
• Water temperatures are more constant and
uniform than land temperatures.
• Temperatures of land areas located near
oceans do not change as much as interior
land areas.
Factors that Affect Climate
Proximity to large bodies of water
Example:
City
Location
Average
Temperatures
Newport, OR
44°N, 124°W
Jan. 44° F
July 57° F
Rapid City, SD
44°N, 103°W
Jan. 22° F
July 72° F
Factors that Affect Climate
Elevation – for every 1,000 feet gained,
the temperature drops about 3.5° F.
• Mt. Kilimanjaro in Africa is located near
the Equator, but is covered with snow
and ice
Changes in Climate
• El Nino – warming of the waters off the west coast of
South America
• About every 7 years, prevailing easterly winds that
blow over the central Pacific Ocean slow or reverse
direction
• The winds push warm ocean water toward the
Americas causing floods and mudslides, Australia
and Asia experience drought conditions
• The reverse is called La Nina – this causes an
increase in precipitation in places such as India and
dryness along the Pacific coast of the Americas
Changes in Climate
• Global Warming – although controversy
exists over the causes of global warming,
scientists agree temperatures are increasing
• Some believe the cause is the greenhouse
effect – layer of gases released by burning of
coal and petroleum traps some solar energy,
causing higher temperatures
• Scientist predict that, if global warming
continues, ice caps will melt, flooding some
coastal areas, covering islands, and changing
the global climate
5 Major Climate Regions
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Tropical
Dry
Mid-Latitude
High-Latitude
Highlands
• See pages 60-61
Types of Precipitation
• Convectional –hot, humid air rises and
cools losing its ability to hold water (ex.
Tropical rainforest)
• Orographic – warm moist air is forced
up when passing over high landforms
• Frontal – 2 fronts of different
temperatures meet
Convectional Precipitation
Frontal Precipitation
Orographic Precipitation
Four Types of Vegetation
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Forest
Grassland
Desert
Tundra
Forest
• Tropical rainforest
• Deciduous forest – broadleaf, such as
maple and oak
• Coniferous forest – cone bearing,
evergreens
• Chaparral
Forest
Grassland
• Tropical grasslands (savannas)
• Temperate grasslands (prairies,
steppes, pampas)
Grasslands
Desert
• A desert can occur where there is a
lack of precipitation, less than 10
inches a year.
• Deserts can be cold, they do not
have to be hot and sandy.
• Vegetation – plants that can
conserve water & withstand heat
such as cacti & sagebrush
Desert
Tundra
• Alpine tundra
• Arctic tundra
• Vegetation –
includes mosses
& lichens
Anaktuvuk Pass, Alaska