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Chapter 3
Climate and Vegetation
Section 1
Seasons and Weather
Seasons
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Earths Tilt- the earth is tilted at a 23.5% angle in
relationship to the sun. This means that different
parts of world receive direct sun rays more hours of
day at different times of the year. This affects our
weather and climate.
Two latitude lines the tropic of Cancer and the tropic
of Capricorn mark the farthest points north and south
that the sun shines directly over head at noon. The
days that this occurs is called the solstice.
Seasons Cont.
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Summer solstice is the longest day of the
year and marks the beginning of summer.
Winter solstice is the shortest day of the year
and marks the beginning of winter.
Another signal for seasonal change are the
equinoxes. Equinox occurs twice a year
when the days and nights are of equal link all
over the world.
Seasons Cont.
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The equinoxes mark the beginning of spring
and autumn (fall).
Weather
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Weather-is the condition in the atmosphere
at a particular location and time.
Climate-is the term for weather conditions in
a particular place over a long period of time.
Weather
What causes weather?
 Water vapor-this determines whether there
will be precipitation. Precipitation-is falling
water droplets in the form of rain, sleet, snow,
or hail.
 Cloud cover-clouds hold water vapor
 Landforms and Bodies of Water-Water heats
slowly and looses heat slowly. Land heats
quickly and looses heat quickly.
Weather Cont.
Causes of Weather Cont.
 Elevation-as elevation increases the air
becomes thinner and looses its ability to hold
water.
 Air Movement-wind moves solar energy and
air. Moisture is also moved as the air it is in
moves. Weather can change very rapidly.
Weather Cont.
Precipitation Precipitation depends on the amount of
water vapor in the air. As warm air rises it
cools and loses its ability to hold water vapor.
The water vapor condenses and forms into
clouds. When the clouds become to heavy
precipitation falls.
 There are three categories of precipitation.
Weather Cont.
Types of precipitation Convectional-Sun heats warm moist air,
clouds form and rain falls.
 Orographic-occurs in mountain areas. Rain
occurs on the windward side of the mountain
and little rain occurs on the leeward side of
the mountain. The land on the leeward side
is called a rain shadow because it gets little
rain due to descending dry air.
Rain Shadow animation
Weather Cont.
Types of Precipitation Frontal-this type of precipitation usually
occurs in the middle latitudes when cold
dense air masses push lighter warm air
masses upward causing precipitation to fall.
Convectional, Orographic, Frontal
Weather Extremes
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Hurricanes-storms that form over warm
tropical waters. They are know as typhoons
in Asia. When air flows over ocean waters
that are 80 degrees, the winds pick up large
amounts of moisture and heat energy. As the
winds flow into a low pressure core they
tighten and form eyes. Hurricanes can reach
wind speeds up to 200 miles per hour. They
cause wind damage and flooding.
Weather Extremes
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Tornado-powerful funnel shaped column of
spiraling air. Wind can reach speeds of 300
miles per hour. Tornados can occur with out
warning and cause catastrophic damage.
Blizzard-heavy snow storm with winds of 35
miles per hour or greater.
Drought-long period of time without rain.
Texas went through a drought in 2000 (84
days without rain).
Section 2
Climate
Factors Effecting Climate
Wind Currents Wind currents help distribute the sun’s heat
from one place to another. Convection is
transfer of heat in the atmosphere by upward
motion of the air. Warm air flows to the poles
and cold air flows towards the equator. The
actual wind currents bend due to the rotation
of the earth.
Factors Affecting Climate
Ocean Currents Ocean currents are like large rivers flowing
through the ocean. Cold currents flow
toward the equator and warm currents flow
toward the poles. Winds that blow across
these currents create climate. For example
Europe has a mild climate even though it is a
far north as Canada. This is caused by the
Gulf Stream and North Atlantic Drift.
Factors Affecting Climate
Zones of Latitude The world is divided into three latitude
zones
1. Low-Tropical Climate
2. Middle-Temperate Climate
3. Higher-Polar Climate
Factors Affecting Climate
Elevation-The higher the elevation the cooler
the climate.
Topography-Landforms such as mountains
affect climate. Remember from section two
the windward side of a mountain gets more
precipitation than the leeward side.
Changes In Climate
Climate changes over time. Some changes are
natural and some changes occur as the
result of human activity.
El Nino- Warming waters off the west coast of
South America cause above average rain in
the Americas.
La Nina-Is the opposite of El Nino and causes
dryer patterns in the Americas and wetter
patterns in Asia.
Section 3
World Climate Regions
Defining A Climate Region
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Climate regions can tell geographers many
things about a region without actually giving
many local details. Temperature and
precipitation are the two most important
factors in defining a climate. Topography and
elevation also define climates. Latitude
zones are also used to determine climate.
There is a transitional zone on the borders of
climate zones.
http://www.classzone.com/books/earth_science/terc/c
ontent/visualizations/es2103/es2103page01.cfm?chap
ter_no=21
Types Of Climates
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Tropical Wet- little variation in temperature
(80 degrees). Rain fall averages over 80in
per year. (Central and South America, Africa,
and parts of Asia.)
Tropical Wet and Dry- Rainy summers and
dry winters. These climate zones border
tropical wet climate zones. (Central and
South America, Africa, and parts of Asia.)
Types Of Climate
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Semiarid- Receives around 16in. of rain per year.
Summers are hot and winters are mild to cold.
Usually some of the most productive agricultural
lands.
Desert- Deserts are classified for the amount of
rainfall they receive. Hot deserts like the Sahara are
mostly sand. However the deserts in the northern
hemisphere that are created by rain shadows can be
warm in the summer and freezing in the winter.
Types Of Climate
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Mediterranean- Summers are dry and hot,
winters are cool and rainy. The west coast of
the U.S. has a Mediterranean climate.
Marine West Coast- Cloudy, cool, and damp
with consistent temperatures. Washington,
Oregon, Canada, Northern California.
Humid Subtropical- La Granges Climate.
Humid and hot summers with cool winters.
Types Of Climates
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Humid Continental- Great variety in
temperature and precipitation. They truly
experience all four seasons.
Subartic- Huge temperature swings in the
seasons. Evergreen forest with short cool
summers and long cold winters.
Tundra-Flat treeless lands forming a ring
around the artic circle. Permafrost-year
round frozen sub-soil.
Types Of Climate
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Ice Cap- Snow, Ice, and permanent freezing
temperatures. Coldest temperature ever
recorded 128 below zero.
Highlands- temperature and precipitation
vary with latitude, elevation, and other
topography. Many times it depends on which
side of the mountains you are on.
Section 4
Soils and Vegetation
Soil Regions
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Soil is a thin layer of weathered rock, humus,
air, and water. The worlds food supply
depends on the first six inches of soil called
top soil. The quality of top soil determines
what vegetation can be grown.
Vegetation Regions
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Natural environments that provide farming,
raising of livestock, and timber production.
Ecosystem-an interdependent community of
plants and animals.
Biome-an ecosystem of a region.
Vegetation Regions
Forest regions are categorized by the types of
trees they support.
Deciduous-broad leaf trees such as maple,
oak, birch, and cottonwood. These trees
shed their leaves once a year.
Coniferous-Cone bearing needle leaf trees.
Vegetation Regions
Grasslands
 Savannas are flat, grassy, mostly treeless
plains in tropical grassland regions.
 Steppe is a term used to name grasslands
that are temperate in the northern
hemisphere. They are also called praires.
Vegetative Regions
Desert and Tundra
 The plants that live in these extreme climates
have adapted over time to tolerate the
conditions.
Human Environment
We have a huge impact on the plants and
landscape of planet earth. We have made
many changes for good and bad.