LAB MODULE 5: GLOBAL TEMPERATURE PATTERNS
Note: Please refer to the GETTING STARTED lab module to learn how to maneuver
through and answer the lab questions using the Google Earth ( ) component.
KEY TERMS
You should know and understand the following terms:
Air temperature Heat index Temperature anomalies
Altitude Kelvin (K) Temperature averages
Ambient temperature Latitude Thermopause
Axial Tilt Maritime effect Thermosphere
Celsius (C) Mesopause Tropopause
Continentality, or
Continental effect
Mesosphere Troposphere
Stratopause Urban heat island
Environmental Lapse Rate Stratosphere Urban heat island effect
Exosphere Structure of the atmosphere Wind chill
Fahrenheit (F) Surface temperature
LAB MODULE LEARNING OBJECTIVES
After successfully completing this module, you should be able to the following
tasks:
Describe the differences between air and surface temperature
Explain heat index and wind chill
Explain the urban heat island effect
Describe the structure of the atmosphere
Describe large scale factors influencing temperature
Describe local factors influencing temperature
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INTRODUCTION
This lab module explores the global surface and air temperatures of Earth and
Earth’s atmosphere. Topics include the structure of the atmosphere, local and
global factors influencing temperature, and temperature anomalies. The modules
start with four opening topics, or vignettes, which are found in the accompanying
Google Earth file. These vignettes introduce basic concepts of the internal structure
of the Earth. Some of the vignettes have animations, videos, or short articles that
will provide another perspective or visual explanation for the topic at hand. After
reading the vignette and associated links, answer the following questions. Please
note that some links might take a while to download based on your Internet speed.
Expand the INTRODUCTION folder.
Read Topic 1: Surface and Air Temperature
Question 1: How do the surface temperatures of the countries in the
northern latitudes (for example, Canada, Iceland, Norway, and Russia)
compare to those of northern Africa (for example, Algeria, Egypt, Libya,
Morocco, and Sudan)?
A. The temperatures are higher in the northern latitudes during summer
months when net radiation is higher.
B. The temperatures are lower in north Africa during the summer months
when net radiation is higher in northern latitudes.
C. Temperatures are lower in northern latitudes year-round.
D. Temperatures are only lower in the northern latitudes during winter
months.
Read Topic 2: Measuring Temperature
Question 2: Considering water freezes (or alternatively, melts) at 0˚C,
determine from the map which countries or landmasses have an annual
mean temperature around 0˚C.
A. Canada and Norway
B. The United States and the United Kingdom
C. Greenland and Antarctica
D. Russia and Antarctica
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Read Topic 3: Heat Index and Wind Chill
Question 3: The heat index on a warm day (86˚F or 30˚C) when the
relative humidity is 50% is:
A. 87F B. 90F
C. 31C D. 33F
Read Topic 4: Human Interaction
Question 4: Identify three negative impacts of heat islands.
A. Increased energy consumption, elevated greenhouse gases, improved
water quality
B. Compromised human health, lower energy consumption, lower water
quality
C. Decreased greenhouse gases, higher energy consumption, compromised
human health
D. Increased greenhouse gases, greater air pollution, increased energy
consumption
Collapse and uncheck the INTRODUCTION folder.
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GLOBAL PERSPECTIVE
Perhaps you recall news reports on extreme temperature-related weather patterns,
such as the 2010-2011 colder-than-normal winter in the western USA, or the 2003
European summer heat wave (which led to more than 35,000 deaths). These
examples are temperature anomalies, as they deviate significantly from
temperature averages that are based on decadal (or longer) year records.
Temporary temperature anomalies are usually due to non-permanent weather
phenomena like a passing storm or seasonal drought; however, more permanent
temperature anomalies could signify the presence of urban heat islands, and if
widespread, global climate change. Temperature anomalies can have significant
impacts on farming and ranching, recreation, and even human health.
Expand the GLOBAL PERSPECTIVE folder and then check Temperature
Anomalies in January. To close the citation, click the X in the top right corner
of the window.
This imagery uses the following color scheme to show land surface temperature
anomalies during the month of January 2011 as compared to average conditions for
the month in 2000 to 2008:
Red – warmer-than-average temperatures
Blue – cooler-than-average temperatures
Black – no data
Temperatures ranged from 12˚C below to 12˚C above the normal January
temperature.
Verify that Borders and Labels and Places are checked in the Layers panel. To note, you might have to zoom in or out for the location name to appear.
Double-click and select Location A.
Question 5: What is the name of this US county? (You might have to zoom
in to see place names.)
A. Lasalle
B. Bureau
C. Putnam
D. Marshall
Question 6: Is the temperature anomaly warmer or colder?
A. The anomaly is warmer
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B. The anomaly is colder
C. There is no anomaly, temperature is the same
D. Unable to discern
Double-click and select Location B.
Question 7: What is the name of the European city?
A. Ludres
B. Frouard
C. Nancy
D. Toul
Question 8: Is the temperature anomaly warmer or colder?
A. The anomaly is warmer
B. The anomaly is colder
C. There is no anomaly, temperature is the same
D. Unable to discern
Double-click and select Location C.
Question 9: What is the name of the capital city?
A. Windhoek
B. Okahandja
C. Pretoria
D. Khomas
Question 10: Is the temperature anomaly warmer or colder?
A. The anomaly is warmer
B. The anomaly is colder
C. There is no anomaly, temperature is the same
D. Unable to discern
Uncheck Temperature Anomalies in January.
Double-click and select Temperature Anomalies in August. To close the
citation, click the X in the top right corner of the window.
This imagery shows land surface temperature anomalies during the month of
August 2003.
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Return to Location B.
Question 11: What is the temperature anomaly (in °C)?
A. -12°C
B. -4°C
C. 4°C
D. 10°C
Question 12: How does this anomaly compare to the one in January 2011?
A. The anomaly is warmer
B. The anomaly is colder
C. There is no anomaly, temperature is the same
D. Unable to discern
Collapse and uncheck the GLOBAL PERSPECTIVE folder.
STRUCTURE OF THE ATMOSPHERE
The structure of the atmosphere impacts temperature. To begin, Earth’s
atmosphere is not uniform, but is comprised of layers. The layer closest to the
surface is called the troposphere. Because the troposphere’s temperature is based
on long wave radiation emitted from the Earth’s surface, temperature decreases
with elevation in this layer of the atmosphere. This change in temperature with
altitude is called the environmental lapse rate.
Click STRUCTURE OF THE ATMOSPHERE. Watch the animation and answer
the following questions:
Question 13: Why does the temperature increase in the upper portion of
the stratosphere?
A. Because long wave radiation is heating the earth’s surface
B. Because ozone blocks ultra-violet radiation and releases heat
C. Because clouds are able to trap heat
D. Because heat is trapped in this portion of the atmosphere
Question 14: Because temperature increases as altitude increases in the
stratosphere, is the environmental lapse rate positive or negative?
A. The lapse rate is positive
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B. The lapse rate is negative
C. The lapse rate is zero
D. Unable to discern
Question 15: Why are temperatures in the thermosphere so high?
A. Because this layer is closest to the sun
B. Because of intense solar radiation
C. Because there are so few molecules
D. Because of the lack of pollutants
Question 16: Would it feel hotter on a warm summer day in the
thermosphere or the troposphere? (Hint: Think composition!)
A. In the thermosphere because temperature reaches over 1000F
B. In the troposphere because temperature reaches over 1000F
C. In the thermosphere because of the intense solar radiation
D. In the troposphere because there are more air molecules to retain heat
The environmental lapse rate can be used to determine a given temperature of a
location, provided that the lapse rate and altitude are known. The standard
environmental lapse rate as you go up in altitude is 6.4 ˚C/1000m. In other words,
as you go up 1000 meters, the temperature decreases 6.4˚C
For the following questions, however, assume a negative environmental lapse rate
of 6.4˚C/1000m.
So how do you solve this? Here is an example:
You have a location – Town M. Town M that has an altitude of 100m and its air
temperature is 10˚C. At 1000m the air temperature is different – but what is it?
How do we figure out the temperature at 1000m?
To solve:
First, make sure you know the initial temperature and distance between the start
location and the end location.
Initial temperature: 10˚C
Distance: 1000m – 100m = 900m
Next, let’s set up the equation:
Environmental lapse rate = x/distance
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Where x is the unknown air temperature for Town M. Plug in the numbers and
units:
6.4˚C/1000m = x/900m
Now we multiply 900m on both sides.
6.4˚C*900m/1000m = x/900m * 900m
6.4˚C*900m/1000m = x
The m/m means that the meters cancel out, leaving only ˚C as a unit. If we do the
math, our answer is as follows:
x = 6.4˚C*900m/1000m
x = 5.76˚C
This value means your change in temperature was 5.76˚C. Now, take the initial
temperature value (10 ˚C) and subtract the calculated x temp (5.76˚C) from it.
10 ˚C – 5.76˚C = 4.24 ˚C
Note that this is a negative environmental lapse rate – meaning you subtract going
up in elevation, and add going down in elevation.
Question 17: The altitude in town N is 1000m and the air temperature is
22˚C. What is the air temperature (in˚C) at 3000m?
A. 22˚C – (3000m-1000m)*6.4/1000m = 9.2˚C
B. 22˚C + (3000m-1000m)*6.4/1000m = 34.8˚C
C. 22˚C – (3000m-1000m)*5.76/1000m = 10.5˚C
D. 22˚C – (3000m-1000m)*5.76/1000m = 33.5˚C
Question 18: The altitude in town P is 1000m and the air temperature is
18˚C. What would be the temperature (in ˚C) of Town P if it were located
instead at 500m?
A. 18 – (1000m-500m) *6.4/1000m = 21.2˚C
B. 18 – (1000m-500m) *6.4/1000m = 14.8˚C
C. 18 + (1000m+500m) *6.4/1000m = 27.6˚C
D. 18 – (1000m+500m) *6.4/1000m = 9.0˚C
Uncheck the STRUCTURE OF THE ATMOSPHERE folder.
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FACTORS INFLUENCE AIR TEMPERATURE
Global Scale Factors
There are several global-scale factors that influence air temperature. These include
latitude, axial tilt (and length of day), and time of day.
Latitude
Latitude affects net radiation (energy). Locations in lower latitudes (for example,
near the Equator) have net gain (or surplus) of radiation, while higher latitudes (for
example, near the North or South Pole) have a net loss (or deficit) of radiation.
Where there is a surplus of energy, there are higher air temperatures. Thus,
tropical and sub-tropical regions have a higher annual average air temperature than
polar and sub-polar regions.
Axial Tilt
The tilt of the Earth’s axis is one of the major reasons the Earth has seasons. The
location where the most energy from the Sun (as sunlight) directly hits the Earth’s
surface is called the subsolar point. In the Northern Hemisphere in June, the
subsolar point is at or near the Tropic of Cancer (23.5 degrees North of the
Equator) and the days are longer. In contrast, the subsolar point is furthest from
the Northern Hemisphere in December (23.5 degrees South of the Equator) and the
days are shorter. As a result, the air temperature in the Northern Hemisphere is
higher in June (thereby summer) and lowers in December (thereby winter).
Time of day
Lastly, the time of day affects air temperature. Usually, the temperature is warmer
during the day and cooler at night. Local noon time is the peak of solar radiation.
However, there is a temperature lag, and the peak air temperature is usually a few
hours after the peak of solar radiation. This is because the sunlight reaching the
Earth’s surface needs time to heat it up, and then re-radiate the energy back into
the atmosphere as long wave (thermal) radiation.
Expand the AIR TEMPERATURE folder and then expand the Global-Scale
Factors folder.
Select Day Temperatures in December. To close the citation, click the X in
the top right corner of the window.
Double-click and select Location D.
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Question 19: Estimate the average monthly daytime temperature in
December for this location.
A. 0°C
B. 5°C
C. 15°C
D. 25°C
Question 20: Record the latitude for this location.
A. 58N
B. 58S
C. 34N
D. 34S
Double-click and select Location E.
Question 21: Estimate the average monthly daytime temperature in
December for this location.
A. 0°C
B. 5°C
C. 10°C
D. 25°C
Question 22: Record the latitude for this location.
A. 33S
B. 33N
C. 84N
D. 84S
Question 23: What global-scale factor(s) accounts for the temperature
difference between Locations D and E? Check all that apply.
A. Latitude
B. Axial tilt
C. Time of day
D. All of the above
Click Night Temperatures in December. To close the citation, click the X in
the top right corner of the window.
Double-click and select Location F.
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Question 24: Estimate the average monthly night time December
temperature for location F.
A. -20°C
B. 0°C
C. 5°C
D. 15°C
Double-click and select Location G.
Question 25: Estimate the average monthly night time December
temperature for location G.
A. -15°C
B. 0°C
C. 5°C
D. 10°C
Question 26: Account for the temperature difference you recorded for
Location F and G.
A. Latitude
B. Axial tilt
C. Time of day
D. All of the above
Question 27: What global-scale factor(s) accounts for the temperature
difference you recorded between Locations E and F?
A. Latitude
B. Axial tilt
C. Time of day
D. All of the above
Collapse and uncheck the Global-Scale Factors folder.
Local Scale Factors
In addition to large-scale factors influencing temperature, there are also three
notable local-scale factors; namely, proximity to a large body of water (maritime
effect versus continentality), altitude, and the urban heat island effect.
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Maritime versus Continental
The maritime/continental
factor refers to the
proximity to a large body of
water. If a location is
located near the ocean (like
Seattle, Washington, USA),
its temperature is
influenced by a maritime
effect. This means that
average temperatures are
moderated, and are not
significantly higher than the
average in the summer or
significantly lower than the
average in the winter months. Conversely, locations experiencing a continental
effect on their temperatures (like Lincoln, Nebraska, USA) have colder
temperatures in the winter and warmer temperatures in the summer months.
Figure X illustrates the maritime/continental effect on temperature. In the winter
months, Seattle, Washington is up to 16F warmer than Lincoln, but in the summer
months, Lincoln is 14F warmer than Seattle.
Altitude
Altitude is the second local
factor affecting
temperature. In general,
locations at a lower altitude
have a warmer temperature
than those at a higher
altitude. The temperatures
of both Denver, Colorado
and Kansas City, Missouri
are located roughly at
latitude of 39°N, and are
influenced by the
continental effect. However,
Denver is located at approximately 5,280 feet, while Kansas City is located at
approximately 973 feet in elevation. Figure 2 shows that on average, temperatures
are warmer in Kansas City, MO than in Denver, CO, owing in large part to a
difference in altitude.
Figure 2. Average monthly temperatures for Denver and Kansas City.
Figure 1. Average monthly temperatures for Seattle and Lincoln.
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Urban Heat Island
An urban heat island is a
phenomenon in which
urban areas are generally
warmer than the
surrounding rural areas.
This is due to the amount
of impervious surfaces
such as roads, buildings
and parking lots found in
urban centers. These
surfaces, plentiful within
most urban areas, tend to
emit more long wave radiation (heat energy) than do rural areas dominated by
natural vegetation, crops or soil.
Figure 3 illustrates the urban heat island effect. Atlanta is a major city in the US,
while Acworth is a small city located northwest of downtown Atlanta. The graph
shows that temperatures are slightly warmer in urban Atlanta, compared to
suburban Acworth.
Before you begin this section, make sure that you have Borders and Labels
selected under the Layers panel in Google Earth.
Expand the Local Scale Factors folder.
Check Average Temperature in July.
Double-click and select Location H.
Question 28: Estimate the average monthly July temperature for Location
H.
A. 0°C
B. 5°C
C. 15°C
D. 25°C
Double-click and select Location I.
Question 29: Estimate the average monthly July temperature for Location I.
A. 0°C
Figure 3. Average monthly temperatures for Atlanta and Acworth.
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B. 5°C
C. 15°C
D. 25°C
Question 30: What of these local-scale factors – continental versus
maritime effect, altitude, or urban heat island effect – is most influencing the
difference in temperature between Locations H and I?
A. Maritime effect
B. Altitude
C. Urban heat island
D. None of the above
Double-click and select Location J.
Question 31: Estimate the average monthly July temperature for Location J.
A. 0°C
B. 5°C
C. 15°C
D. 30°C
Double-click and select Location K.
Question 32: Estimate the average monthly July temperature for Location
K.
A. 0°C
B. 5°C
C. 15°C
D. 25°C
Question 33: What of these local-scale factors – continental versus
maritime effect, altitude, or urban heat island effect – is most influencing the
difference in temperature between Locations J and K?
A. Maritime effect
B. Altitude
C. Urban heat island
D. None of the above
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Double-click and select Location L.
Question 34: Estimate the average monthly July temperature for Location L.
A. 0°C
B. 5°C
C. 15°C
D. 20°C
Double-click and select Location M.
Question 35: Estimate the average monthly July temperature for Location
M.
A. 0°C
B. 5°C
C. 15°C
D. 20°C
Question 36: What of these local-scale factors – continental versus
maritime effect, altitude, or urban heat island effect – is most influencing the
difference in temperature between Locations L and M?
A. Maritime effect
B. Altitude
C. Urban heat island
D. None of the above
Question 37: What of these local-scale factors – continental versus
maritime effect, altitude, or urban heat island effect – would most likely show
same trend in average monthly temperature in January as in July? (Hint:
Figures 1-3)
A. Maritime effect
B. Altitude
C. Urban heat island
D. None of the above
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Question 38: What of these local-scale factors – continental versus
maritime effect, altitude, or urban heat island effect – would likely show an
opposite trend in average monthly temperature in January as in July? (Hint:
Figures 1-3)
A. Maritime effect
B. Altitude
C. Urban heat island
D. None of the above
Collapse and uncheck the Local-Scale Factors folder. You have completed Lab
Module 5.