Download 2 Climate Zones

Name
CHAPTER 22
Class
Date
Climate
2 Climate Zones
SECTION
KEY IDEAS
As you read this section, keep these questions in mind:
• What are the characteristics of the three types of
tropical climates?
• What are the characteristics of the five types of
middle-latitude climates?
• What are the characteristics of the three types of
polar climates?
• Why can city climates differ from rural climates?
What Are Climate Zones?
READING TOOLBOX
Climate zones are areas on Earth with different
temperature ranges and amounts of precipitation. Earth
has three major climate zones: tropical, middle-latitude,
and polar. Each zone has a specific temperature range.
The amount of precipitation within each zone varies.
Therefore, each zone also has several types of climates.
What Are the Types of Tropical Climates?
Regions at or near the equator that have high
temperatures have tropical climates. Tropical climates
have an average monthly temperature of at least 18 °C,
even during the coldest months. There are three main
tropical climates, as shown below.
Characteristics of Tropical Climates
Climate
Temperature and Precipitation Description
Rain forest • small temperature range
• annual rainfall of about
200 cm
• dense, lush vegetation
• high biodiversity
• examples: southeast Asia
and the Amazon River
basin in South America
Desert
• large temperature range
• hot days and cold nights
• annual rainfall of less than
25 cm
• little to no vegetation
• organisms adapted to dry
conditions
• examples: north Africa,
southwestern Asia
Savanna
• small temperature range
• annual rainfall of about 50 cm
• alternating wet/dry periods
• open grasslands with
clumps of drought-resistant
shrubs
• examples: parts of the
following areas: South
America, Africa, southeast
Asia, northern Australia
Summarize Relationships
Create a cause-and-effect
map to show the relationship
between different climate
conditions (cause) and
amount and type of
vegetation (effect). For
example, one climate
condition would be high
temperatures and low
rainfall. Another would be
low temperatures and low
precipitation.
LOOKING CLOSER
1. Compare Which area
has a drier climate—northern
Australia or north Africa?
2. Classify The country of
Belize is located in Central
America. Southern Belize
receives about 160 cm of rain
each year. In which tropical
climate would you classify
southern Belize? Explain.
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Climate
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Climate Zones continued
What Are the Types of Middle-Latitude
Climates?
READING CHECK
3. Define What general
conditions exist in a middlelatitude climate?
Middle-latitude climates have more moderate
temperatures than tropical climates. They have an
average maximum temperature below 18 °C in the
coldest month and above 10 °C in the warmest month.
There are five main middle-latitude climates.
Characteristics of Middle-Latitude Climates
Climate
Temperature and
Precipitation
Description
Marine west
coast
• small annual temperature
range
• between 60 cm and
150 cm of precipitation
each year
• deciduous trees and dense
forests
• mild winters and summers
• example: the Pacific
Northwest of the United
States
Steppe
• drought-resistant
• large annual temperature
vegetation
range
• annual precipitation of less • cold, dry winters
than 40 cm
• warm, wet summers
• example: the Great Plains
of the United States
Humid
continental
• large annual temperature
range
• annual precipitation of
greater than 75 cm
• wide variety of vegetation
and evergreen trees
• variable weather
• example: the northeastern
United States
Humid
subtropical
• large annual temperature
range
• annual precipitation of
75–165 cm
• broadleaf and evergreen
trees
• high humidity
• example: the southeastern
United States
Mediterranean
• small annual temperature
range
• average annual
precipitation of about
40 cm
• broadleaf and evergreen
trees
• long, dry summers
• mild, wet winters
• example: areas near the
Mediterranean Sea and
along the coast of central
and southern California
LOOKING CLOSER
4. Contrast What is
one difference between
humid subtropical and
Mediterranean climates?
Critical Thinking
5. Compare How are a
Mediterranean climate and a
savanna climate similar? How
are they different?
What Are the Types of Polar Climates?
The climates in the polar regions are called polar
climates. These climates all have very low temperatures.
The table on the next page describes the three types of
polar climates.
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Climate
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Climate Zones continued
Characteristics of Polar Climates
Climate
Temperature and Precipitation Description
Subarctic • largest annual temperature
range (63 °C)
• annual precipitation of
25–50 cm
• evergreen trees
• brief, cool summers
• long, cold winters
Tundra
• average temperature below
4 °C
• annual precipitation of about
25 cm
• treeless plains
• nine months of
temperatures below freezing
Polar
icecap
• average temperature below
0 °C
• low annual precipitation (less
than 25 cm)
• few living things
• temperatures below freezing
all year
• high winds
• much of the land and ocean
covered by thick sheets of
ice year-round
Critical Thinking
6. Apply Concepts Certain
areas in the state of
Alaska experience high
temperatures in summer and
very low temperatures in
winter. What type of climate
do these areas have?
What Are Local Climates?
Late afternoon temperatures (˚C)
The climate of a small area is called a microclimate.
Microclimates are influenced by vegetation density and
human-made structures. Human-made structures absorb
solar energy and radiate it as heat. Vegetation does
not radiate as much heat energy. Therefore, average
temperatures may be a few degrees higher in cities than
in rural areas.
35
LOOKING CLOSER
7. Analyze Relationships
What is the general
relationship between
amount of paved surface
and temperature?
30
Downtown
25
Suburban
residential
Rural
Commercial
Park
Rural
farmland
Urban
Suburban
residential residential
Urban areas have more pavement and less vegetation than suburban and rural
areas have.
Elevation and bodies of water can also affect local
climates. As elevation increases, the temperature in an
area decreases. Water absorbs and releases heat more
slowly than land. Therefore, water bodies can moderate
the temperature of nearby land. Large bodies of water
can also increase precipitation. Areas near water have
a smaller range of temperatures and more precipitation
than other locations at the same latitude.
Copyright © Holt McDougal. All rights reserved.
Holt McDougal Earth Science
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Climate
Name
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Section 2 Review
SECTION VOCABULARY
microclimate the climate of a small area
middle-latitude climate a climate that has an
average maximum temperature below 18 °C in
the coldest month and an average minimum
temperature above 10 °C in the warmest
month
polar climate a climate that is characterized by
average temperatures that are near or below
freezing
tropical climate a climate characterized by high
temperatures and heavy precipitation during at
least part of the year
1. Compare On the graph below, write the names of the following climates to
compare their relative temperatures and amounts of precipitation: humid
continental, polar icecap, savanna, subarctic, tropical desert, tropical rain
forest, tundra. One climate has already been placed on the graph for you.
High
temperatures
Tropical rain forest
Low
temperatures, low
precipitation
High
precipitation
2. Identify What are four factors that influence microclimates?
3. Explain Why are cities often a few degrees warmer than surrounding rural areas?
4. Apply Concepts The lowest average monthly temperature in an area is 12 °C. Its
highest average monthly temperature is 17.5 °C. In which climate zone is the area
most likely located?
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Holt McDougal Earth Science
340
Climate