Figure 1 illustrates the atmospheric effects on incoming solar radiation for an
average noon sun angle. Answer questions 6-9 by examining the figure.
Figure 1. Solar radiation budget of the atmosphere and Earth.
5. _______ percent of the incoming solar radiation is reflected and scattered back to
space. [1 pt]
6. _______ percent of the incoming solar radiation is absorbed by gases in the
atmosphere and clouds. [1 pt]
7. _______ percent of the incoming solar radiation is absorbed at the Earth’s surface.
[1 pt]
8. (Two and a half, Four) times as much incoming radiation is absorbed by Earth’s
surface than by the atmosphere and clouds. Circle the correct answer. [1 pt]
Figure 2 illustrates the effects of the atmosphere on various wavelengths of
radiation. Recall from the previous lab using Wien’s law and the calculations and
conclusions from that exercise. Use Figure 2 to answer questions 9-13 by circling the
correct response.
9. The incoming solar radiation that passes through the atmosphere and is absorbed
at the Earth’s surface is primarily in the form of (ultraviolet, visible, infrared)
wavelengths. [1 pt]
10. When the surface of Earth re-emits the solar energy it has absorbed, the
outgoing terrestrial radiation is primarily (ultraviolet, visible, infrared) wavelengths.
[1 pt]
11. (Ultraviolet, Visible, Infrared) wavelengths of radiation are absorbed efficiently
by oxygen and ozone in the atmosphere. [1 pt]
12. (Nitrogen, Carbon dioxide) and (water vapor, ozone) are the two principal gases
that absorb most of the terrestrial radiation in the atmosphere. [2 pt]
13. (Carbon dioxide, ozone) and (oxygen, water vapor) exclusively account for all
the total atmosphere absorption between 0.1 and 0.3μm. [2 pt]
GE101 Natural Environments: The Atmosphere Laboratory 44
Figure 2. The absorptivity of selected gases in the atmosphere and the
atmosphere as a whole.
Assume Figure 1 represents the atmospheric effects on incoming solar radiation for
an average noon sun angle of 50°. Answer questions 14-17 concerning other sun
angles by circling the appropriate responses.
14. If the noon sun angle is 90°, solar radiation would have to penetrate a (greater,
lesser) thickness of atmosphere than with an average noon sun angle. [1 pt]
15. The result of a 90° noon sun angle would be that (more, less) incoming solar
radiation would be reflected, scattered and absorbed by the atmosphere and (more,
less) radiation would be absorbed and reradiated by the Earth’s surface to heat the
atmosphere. [2 pt]
16. If the noon sun angle is 20°, solar radiation would have to penetrate a (greater,
lesser) thickness of atmosphere than with an average noon sun angle. [1 pt]
17. The result of a 20° noon sun angle would be that (more, less) incoming solar
radiation would be reflected, scattered and absorbed by the atmosphere and (more,
less) radiation would be absorbed and reradiated by the Earth’s surface to heat the
atmosphere. [2 pt]
GE101 Natural Environments: The Atmosphere Laboratory 45
18. How is the angle at which a solar beam strikes Earth’s surface related to the
quantity of solar radiation received by each square meter of area. [1 pt]
19. How is the length of daylight related to the quantity of solar radiation received
by each square meter of area at the surface? [1 pt]
Figure 3 presents the annual temperature curves for two cities (A and B) that are
located in North America at approximately 37°N latitude. On any date, both cities
receive the same intensity and duration of solar radiation. One city is in the center of
the continent while the other is on the coast. Use Figure 3 to answer questions 20-
27. Circle your answer.
20. In Figure 3, city (A, B) has the highest mean monthly temperature. [1 pt]
21. City (A, B) has the lowest mean monthly temperature. [1 pt]
22. The greatest annual temperature range (difference between highest and lowest
mean monthly temperatures) occurs at city (A, B). [1 pt]
23. City (A, B) reaches its maximum mean monthly temperature at an earlier date.
[1 pt]
24. City (A, B) maintains a more uniform temperature throughout the year. [1 pt]
25. City A is most likely located (along a coast, in the center of a continent). [1 pt]
26. The most likely location for city B is (coastal, mid-continent). [1 pt]
27. Describe the effect that the location, along the coast or in the center of a
continent, has on the annual temperature pattern of a city. [2 pt]
Figure 3. Mean monthly temperatures Figure 4. Typical daily temperature
for two North American cities. graph for a mid-latitude city.
GE101 Natural Environments: The Atmosphere Laboratory 46
Air temperatures are not constant. They normally change 1) through time at any one
location, 2) with latitude because of changing sun angle and length of daylight and
3) with increasing altitude in the lower atmosphere because temperatures tend to
decrease with altitude
Questions 28-35 refer to Figure 4, the daily temperature graph for a mid-latitude city
on a sunny summer. Complete each question by filling in the correct response.
28. The coolest temperature of the day occurs at _________________________. [1 pt]
29. The warmest temperature of the days occurs at _________________________. [1 pt]
30. What is the daily temperature range (difference between maximum and
minimum temperatures for the day)? [2 pt]
Daily temperature range: ______________°F (______________°C)
31. What is the daily temperature mean (average of the maximum and minimum
temperatures)? [2 pt]
Daily temperature mean: ______________°F (______________°C)
32. Recall the mechanisms for heating the atmosphere. Why does the warmest daily
temperature occur in the mid-to-late afternoon rather than at the time of the highest
sun angle? [2 pt]
33. Why does the coolest temperature of the day occur at about sunrise? [1 pt]
34. How would clouds influence daily maximum and minimum temperatures? [1 pt]
35. On Figure 4, sketch and label a colored line that would best represent a daily
graph for a typical cloudy day. [1 pt]
Regional and Global Patterns of Temperature
The primary reason for global variations in surface temperatures is the unequal
distribution of radiation over the Earth. Among the most important secondary factors
are differential heating of land and water, ocean currents and differences in altitude.
Surface temperatures from location to location can vary greatly. Temperatures are
taken at a specific spot and contoured maps can be generated showing the general
temperature pattern of a region. These contoured lines are called isotherms which
are lines of constant temperature.
Questions 36-48 refer to Figure 6 which shows the World Distribution of Mean
Surface Temperatures (°C) for January and July. Circle and/or fill in the correct
answer when required.
GE101 Natural Environments: The Atmosphere Laboratory 47
36. Analyzing both the January and July map, the general trend of the isotherms on
the two maps is (north-south, east-west). [1 pt]
37. In general, how do surface temperatures vary from the equator toward the
poles? Why does this variation occur? [2 pt]
38. During January and July, the warmest and coldest temperatures occur over
which countries and/or oceans? [2 pt]
Warmest global temperatures: ______________________________________________
Coldest global temperatures: _______________________________________________
39. During January and July, the locations of the warmest and coldest global
temperatures are over (land, water). [1 pt]
Figure 6. World Distribution of Mean Surface Temperatures (°C) for January
and July.
GE101 Natural Environments: The Atmosphere Laboratory 48
40. Calculate the annual temperature range at each of the following locations. You
may need to use an atlas or online site to find these locations. [6 pt]
Coastal Norway at 60°N: _____________°C (_____________°F)
Siberia at 60°N, 120°E: _____________°C (_____________°F)
Equator over the central Atlantic Ocean: _____________°C (_____________°F)
41. Contrast the annual temperature range at coastal Norway and Siberia. Why do
each exhibit such different ranges though they sit on the same latitude? [3 pt]
42. Why is temperature relatively uniform throughout the year in the tropics? [2 pt]
43. Using the two maps in Figure 6, calculate the approximate average annual
temperature range for Boston, MA. [2 pt]
Average annual temperature range: _____________°C (_____________°F)
44. Which global location from question 40 has a range most like that calculated for
Boston? Explain. [2 pt]
45. Trace the path of the 5°C isotherm over North America in January. Explain why
the isotherm deviates from a true east-west orientation where it crosses the Pacific
Ocean onto the North American continent. [2 pt]
46. Trace the path of the 20°C isotherm over North America in July. Explain why the
isotherm deviates from a true east-west orientation where it crosses from the Pacific
Ocean onto the continent. [2 pt]
47. Why do the isotherms in the Southern Hemisphere follow a true east-west
orientation more closely than those in the Northern Hemisphere? [2 pt]
48. Why does the entire pattern of isotherms shift northward between the January
and July maps? [2 pt]
GE101 Natural Environments: The Atmosphere Laboratory 49
Temperature Changes with Altitude
The normal conditions found in the lower 12 kilometers of the atmosphere are a
decrease in temperature with increasing altitude. This temperature decrease with
altitude in the lower atmosphere is called the environmental lapse rate. However, at
altitudes about 12 to 45 kilometers, the atmospheric absorption of incoming solar
radiation causes temperature to increase.
Use Figure 7 to answer questions 49-56.
49. Using the temperature as a guide, label the mesosphere, stratosphere,
troposphere and thermosphere on the temperature profile shown in Figure 7. [4 pt]
50. On Figure 7, draw a line and label the tropopause, mesopause and stratopause.
[3 pt]
Figure 7. Atmospheric temperature profile.
GE101 Natural Environments: The Atmosphere Laboratory 50
51. What is the approximate temperature of the atmosphere at each of the following
altitudes? [6 pt]
10 km: _____________°C (_____________°F)
45 km: _____________°C (_____________°F)
80 km: _____________°C (_____________°F)
52. Using Figure 7, calculate the average decrease in temperature with altitude of
the troposphere in both °C/km and °F/mi. [2 pt]
_____________°C/km (_____________°F/mi)
53. Explain why temperature decreases with altitude in the troposphere. [2 pt]
54. Explain why temperature increases with altitude in the stratosphere. [2 pt]
55. Explain why temperature increases with altitude in the thermosphere. [2 pt]
56. Explain the role of ozone in the stratosphere. What will be the effect on radiation
at the Earth’s surface if there is a decrease of ozone in the stratosphere? [2 pt]
Assume the average, or normal, environmental lapse rate (temperature decrease
with altitude) in the troposphere is 3.5°F per 1,000ft (6.5°C per km)
57. If the surface temperature is 50°F (10°C), what would be the approximate
temperature at 45,000 feet (13,716 meters)? [2 pt]
_____________°F (_____________°C)
58. If the surface temperature is 65°F (18°C), at approximately what altitude would
a pilot expect to find each of the following atmospheric temperatures? [4 pt]
20°F: _____________ feet (-6.67°C: _____________ meters)
0°C: _____________ meters (32°F: _____________ feet)
GE101 Natural Environments: The Atmosphere Laboratory 51
Periodically, the temperature in the Earth’s atmosphere will increase with an increase
in altitude. When this occurs, a temperature inversion is said to be in place.
59. Which two layers of the atmosphere exhibit temperature inversions? [2 pt]
60. Suggest a possible cause for a surface temperature inversion. [2 pt]
SECTION 4.3 – WINDCHILL EQUIVALENT TEMPERATURE
(12 points total)
Windchill equivalent temperature is the term applied to the sensation of temperature
that the human body feels, in contrast to the actual temperature of the air as
recorded by a thermometer. Wind cools by evaporating perspiration and carrying
heat away from the body. When temperatures are cool and the wind speed
increases, the body reacts as if it were being subjected to increasingly lower
temperatures, a phenomenon known as windchill.
61. Refer to Figure 8, the chart diagramming windchill equivalent temperatures.
What is the windchill equivalent temperature sensed by the human body in the
following situations? [3 pt]
Air Temperature (°F) Wind Speed (mph) Windchill Equivalent
Temperature (°F)
5° 5
-20° 55
-35° 30
62. If the air temperature is -20°F and the current wind speed is 40mph, how long
before frostbite sets in? [1 pt]
63. If the windchill equivalent temperature is -48°F and the wind speed is 35mph,
what is the actual air temperature? Under these conditions, how soon before
frostbite sets in? [2 pt]
64. If the actual air temperature is 10°F, what wind speed would give you a windchill
equivalent temperature of -19°F? Under these conditions, how soon before frostbite
sets in? [2 pt]
GE101 Natural Environments: The Atmosphere Laboratory 52
65. If the wind speed maintains a sustained speed over a 24-hour period (12am to
12am), when do you believe the lowest windchill equivalent temperature would be
experienced? Why? [2 pt]
66. Write a brief summary of the effect of wind speed on how long a person can be
exposed to the elements before frostbite develops. Use Figure 8 and the previous
questions for guidance. [2 pt]
Figure 8. Windchill chart adopted in November 2001. Fahrenheit
temperatures are used here because this is how the National Weather
Service and the news media in the United States commonly report windchill
information. The shaded areas on the chart indicate frostbite danger. Each
shaded zone shows how long a person can be exposed before frostbite
develops. (After NOAA, National Weather Service)
