Physical Geography
Spring, 2015
A. J. Allred, Adjunct
Student Name __________________
Mid-Term Exam
Explanations
1. The Köppen system of climate classification is based on ________.
a. solar radiation and rainfall
b. temperature and precipitation
c. temperature comparisons between months
d. latitude and temperature
e. cloud cover, humidity and precipitation
Note to Question 1: Monthly average temperature and monthly average precipitation are the key factors that
control climate and weather. Koppen does start with the “big six” climate zones that are bounded by latitude
or altitude. But even with the “big six” temperature and precipitation are the important factors that
distinguish between climates and weather.
2. What is the maximum possible duration of a hurricane at a location where the storm track is
moving forward at 10 mph and the storm is 300 miles in diameter?
a. 30 hours
b. 300 hours
c. 30 minutes
d. 3 days
e. There is no way to know based on the information provided
Note to Question 2: SLCC has a goal for students to be more quantitative, spatial and visual in problem
solving. So, in class we took the example of a slow-moving hurricane that contains high-speed wind. The
speed of winds inside the hurricane don’t determine how quickly the hurricane moves from place to place.
Instead, the ground speed (the speed along the surface of the Earth) and width of the storm matter.
If you are “driving” along with the storm in your car, how far can you go at 10 miles per hour? In 30 hours,
you could go – 30 X 10 = 300 miles.
3. Scientific evidence supports belief that in recent decades a negative feedback loop is developing as
shelf ice melts.
True ___
False ___
Note to Question 3: As floating ice (pack ice, shelf ice) melts, the albedo goes from highly reflective to
highly absorptive. The warmer the water, the more it melts ice, and the more ice melts, the more it is
replaced by warming water. That is a good example of a positive cycle – change leads to more of the same.
4. Climate in the region that includes Logan, Utah is best described by which combination of Köppen
types below?
a. BSk and H
b. BWh and H
c. BSh and Dwc
d. H and BSh
e. None of the above
Note to Question 4: Utah is chronically dry, so the major group ‘B’ applies. We are not true ‘hard-core’
hot, sandy desert (W); instead, we have grasses, shrubs and trees, so the ‘S’ Steppe sub-category applies.
Because northern Utah has cold winters, we are probably within the ‘k’ for cold sub-category. Logan is
definitely colder than most of Utah.
We also have a lot of high mountains, so ‘H’ applies as well.
5. Freezing water releases heat, adding warmth to nearby objects. Inside a turbulent storm cloud,
condensation also tends to result in warming.
True ___
False ___
Note to Question 5: When water goes from liquid to solid, energy must be given up so that kinetic motion of
water molecules slows down enough to form crystal structures. Nearby objects must be available to absorb
that excess energy. If they are, then they warm up as they take on the thermal energy that is given up when
water freezes.
Condensation also involves a change in state: water in vapor holds more energy than liquid water, so for
vapor to condense back to liquid, latent heat must leave the vapor. The air nearby absorbs that excess heat as
water goes from high kinetic motion (vapor) to lower kinetic motion (liquid).
Compare to Questions 21 and 50 below.
6. The main reason for the occurrence of subtropical deserts around the world is _______.
a. the location of anti-cyclones
b. westerly winds
c. the ITCZ
d. easterly winds
e. position of cold ocean currents
Note to Question 6: Clockwise anti-cyclones tend to occur where air is sinking, because it is either colder or
drier than other air. Deserts and dry country tend to prevail under the sinking side of Hadley cells.
The ITCZ is located at the opposite end of Hadley cells, exhibiting rising air that tends to be warmer and
wetter than other air. If Coriolis force is present, then low-pressure cyclones will tend to rotate counterclockwise, the opposite of anti-cyclones.
Cold ocean currents can contribute to dryness because they promote more dense air that sinks, rather than
promoting evaporation that leads to humid air that rises to promote precipitation later on.
7. At its pole-ward margin the Af climate is bounded by climate zones that have dry winters. Winters
are dry there because the ITCZ is hosting rainy summers on the opposite side of the Equator at
that same time.
True ___
False ___
Note to Question 7: The ITCZ follows the Sun as its overhead location migrates north and south during the
year. When the sun is overhead somewhere far above or below the Equator, then regions located on the
opposite side of the Equator will have their dry season because they are at their furthest from having the Sun
and the ITCZ overhead.
So, for example, when the ITCZ is far south of the Equator that area will be having its rainy season.
Therefore, the opposite end of Hadley circulation will tend to be more dry, because it is far from the ITCZ.
8. Based on class discussion and the textbook, the following sequence is in the most appropriate order
for provoking an afternoon convective rainstorm.
- 1st: change in thermal, or kinetic molecular movement
- 2nd: change in air pressure
- 3rd: change in wind
- 4th: change in humidity
- 5th: precipitation
- 6th: cloud formation
True ___
False ___
Note to Question 8: The first step in all weather is the presence or absence of solar energy that leads to
heat. Heat causes changes in air pressure, which leads to wind. Wind evaporates and moves water.
Eventually air cools enough for whatever reason, leading to condensation and precipitation.
Clouds form when air is cooling to condensation. Precipitation won’t occur if there are no clouds of liquid
water, so cloud formation is an earlier step before precipitation.
9. In the northern hemisphere, looking down on a storm moving northward, which part of the storm
should show the weakest winds?
a. Southwest side (left rear).
b. Southeast side (right rear).
c. Northeast side (right front).
d. Northwest side (left front).
e. Inside the ‘eye of the storm.
Note to Question 9: A baseball player will often run before throwing a ball. Running adds speed to the
speed of the ball.
Likewise, the forward motion of the storm adds to the speeds of whatever winds are going in that same
direction. So, looking down a rotating storm, winds on the right side of the storm will be going the same
direction as the storm itself. Add the speed of the winds inside the storm to the forward motion of the
storm itself.
For a north-moving storm, winds on northeast side will be faster because the forward motion of the storm
itself adds to wind speeds inside the storm. Likewise, winds on the southwest side of the storm will feel
slower because the storm itself is moving in the opposite direction of winds in the storm.
10. The north end of Hadley cell movement in the southern hemisphere helps ensure that:
a. Florida and Alabama have a mild “C” climate with plenty of green landscapes.
b. Arizona is dry.
c. regions near the Equator are rainy and humid.
d. Answers ‘b’ and ‘c’ above are correct.
e. Answers ‘a’ and ‘b’ above are correct.
Note to Question 10: In the southern hemisphere, the north end of Hadley cells centers over the Equator,
producing tropical, humid weather.
Hadley cell flow in the southern hemisphere really doesn’t affect places in the northern hemisphere, so
answers ‘a’ and ‘b’ above really don’t apply.
11. In the northern hemisphere, an anti-cyclone involves air that is:
a. turning counter-clockwise while rising.
b. turning clock-wise while sinking.
c. turning counter-clockwise while sinking.
d. rising, and then falling later.
e. answers “a” and “d” above are correct.
Note to Question 11: Coriolis force tends to cause winds to turn right-ward. So, descending air (dry and/or
cold) will diverge as it reaches the surface and spreads out. Coriolis force will cause that wind to gradually
turn to the right until it is flowing in a circular, clockwise direction.
In the schematic, look at the diverging red arrows. Coriolis force will cause these
outbound winds to turn clockwise.
12. For general climate patterns, _____________________.
a. latitude varies inversely with climograph temperature curve steepness
b. altitude varies positively with annual average daytime high temperature
c. distance from the ocean correlates positively with the steepness of climograph temperature curves
d. All of the above provide consistent results in describing world climates
e. Latitude varies positively with humidity and precipitation
Note to Question 12: Climate severity increases with increasing latitude, a positive relationship. Equatorial
regions tend to be mildest. High-latitude ‘D’ and ‘E’ climates exhibit really severe swings in temperature.
In fact, a comparison on climographs will show that the most dramatic temperature ‘curves’ will be in higher
latitudes.
Answer ‘a’ does not work, because as latitude increases the steepness of the curve or line for annual
temperature will be more dramatic. Tropical and equatorial temperatures hardly vary at all, so climograph
temperature lines will be almost flat.
Answer ‘b’ is not viable, because high mountains with ‘H’ climate tend to show dramatic daily and annual
temperature swings. Mountain tops can be quite warm on a summer day, and then extremely that same
evening and/or during winter.
Answer ‘c’ is workable because the further we go from the ocean or a large lake the less we enjoy the
moderating influence of water. Large water bodies absorb a vast amount of heat, keeping us cooler in
summer. In winter, that heat radiates out, keeping us warmer. So, southern California beaches tend to be
mild all year, being near the ocean. In contrast, Palm Springs can be quite hot during the day, and very chilly
at night and during winter.
Answer ‘e’ does not work because as we go from the equator toward higher latitudes we go from humid to
very dry ‘B’ climate, then back to humid ‘C’ and ‘D’ climates and then finally to polar ‘E’ climes that are
extremely dry. There is no regular, consistent relationship between latitude and humidity.
13. Which of the following statements is/are true?
a. With all other variables held constant, descending air should gradually become more humid.
b. With all other variables held constant, descending air should gradually become relatively less
humid.
c. With all other variables held constant, relative humidity should be lower at night.
d. With all other variables held constant, a cloudy night should be colder than a starry night.
e. In a BWk climate, severe surface heating results in higher relative humidity.
Note to Question 13: Descending air is gradually compressed, so energy in the air gradually becomes
concentrated, showing higher temperature. Warming air should become relatively drier, because warm air
can hold more moisture, so answer ‘b’ is valid. Answer ‘c’ is not valid, because cooling night air can hold
less moisture, so relatively humidity rises.
A cloudy night should be warmer than a clear, starry night because water in clouds absorbs outgoing
radiation and sends some of it back to the Earth. Clouds are like a blanket, holding in heat at night and
keeping solar energy (and heat) out during the day.
In ‘B’ climates, severe heating raises humidity, because hotter air can hold more moisture. Daily heat could
raise humidity by evaporating water, but in ‘BW’ climates there isn’t much water available. So, daily
heating just makes the air drier instead of more humid.
14. Which of the following is false:
a. Air blowing over a high mountain should be more humid after it descends to the bottom on the
other side.
b. Energy cannot be destroyed, but it can be hidden when it evaporates liquids into vapor. It takes
energy to turn liquid into vapor, but the energy is not lost, nor is the liquid destroyed. They are
just hidden (latent).
c. A ‘swamp cooler’ (evaporative cooler) converts heat into humidity. Heat and water are ‘hidden’
in the air.
d. The energy required for evaporation is stored as vapor, resulting in lower measured temperature
and higher measured humidity.
e. On the way up the mountain, air will cool by decompression.
Note to Question 14: Sinking air will compress as air pressure is higher at lower altitude. Compressing air
becomes warmer as energy is concentrated in a smaller space. So, answer ‘a’ is incorrect: after air descends
it should become drier because it is warming by adiabatic compression as it descends to lower altitude where
air pressure is higher.
15. Based on class discussion, which of the following statements is true? (everyone gets this one for
free)
a. In perfectly dry air, the temperature at 50,000 feet should be 100°F cooler than air at the surface.
b. In perfectly dry air, a ground temperature of 100°F corresponds to a temperature of 80°F at 4,000
feet above that surface.
c. On a hot, sunny day, saturated air at an altitude of 12,000 feet should be frozen.
d. During a weather inversion, air aloft will be cooler than surface air.
e. Cool, dry air will tend to rise easily compared to humid air.
Note to Question 15: I believe the Mid-Term version sent to students had a ‘typo’ or other error of some
kind. This version seems to be OK.
In any case, based on a summarized version of the textbook, dry air tends to cooler by about 5ºF per each
thousand feet of higher altitude. So, at an altitude 4,000 feet higher than ‘ground’ level air should be 20ºF
cooler: 4 X 5 = 20  100ºF – 20ºF = 80ºF.
16. Which of the following combinations along a weather front boundary is most likely to produce a
severe thunderstorm?
a. 60°F and 35% humidity on one side and 84°F and 10% humidity on the other side.
b. 40°F and 45% humidity on one side and 78°F and 65% humidity on the other side.
c. 40°F and 75% humidity on one side and 50°F and 65% humidity on the other side.
d. All of the conditions above will almost certainly produce severe weather.
e. None of the conditions above are sufficient to produce a storm of any kind.
Note to Question 16: The key to severe thunderstorms is having plenty of heat and humidity available and a
big difference in heat and humidity between colliding air masses.
Answer ‘a’ above shows air warm enough to rise, but not dry enough to rise rapidly because it does not
contain much latent heat. Answer ‘b’ is much better because not only is one air mass much warmer than the
other, but it is also much more humid, so there is plenty of energy for air to rise quickly. Rapidly rising air is
a major key to the high wind speeds in severe storms.
17. In tropical climates, weather is so monotonous that daily temperature swings are greater than
monthly average variation across an entire year.
True ___
False ___
Note to Question 17: The textbook describes tropical regions as having seasonal weather that varies so little
that air temperature changes more between day and night than across the entire average winter and summer.
In fact, the textbook calls night-time the only ‘winter’ that the tropics get at all. Singapore was described in
class as having classical mild weather, with the coldest month of the year varying by only about two degrees
F over the warmest month.
See also the answer to Question 20 below.
18. After June 21 in the northern hemisphere _______________.
a. days get shorter
b. weather tends to get cooler
c. weather tends to get warmer
d. days start getting longer
e. Answers ‘a’ and ‘c’ are both correct.
Note to Question 18: The northern hemisphere summer solstice occurs about June 20, when day is longest
and night is shortest. After that, days start getting shorter until the winter solstice on about December 20.
Meanwhile, weather tends to keep warming even after the summer solstice because mountain snowpack is
still melting and water bodies are still absorbing heat. So, the hottest day of the year is typically in late July
or even August, long after the days have started getting shorter.
Likewise, the shortest day of the year is not typically the coldest day because land masses and water bodies
have not yet lost all of the heat that they collect during summer. The coldest day of the year tends to be
sometime in January.
19. Areas near the Equator exhibit masses of rising air that collide with cool, dry air to provoke
widespread frontal or wedge thunderstorms.
True ___
False ___
Note to Question 19: Equatorial regions tend to be mild because of uniformity in warm, humid conditions.
The absence of cold, dry air masses and lack of Coriolis force prevents develop of really severe storms.
Instead, frequent air mass thunderstorms can occur daily, with plenty of rain and lightning, but not much
else.
Genuine ‘frontal’ or ‘wedge’ storms involve collision of air masses that differ greatly in temperature and/or
humidity. With Coriolis force, these collisions can result in thunderstorms that are much more vigorous than
simple daily rain storms in the tropics.
20. "Night is winter" is best applied to the ________ climate.
a.
b.
c.
d.
e.
Af
ET
BWk
Csa
Dfa
Note to Question 20: See the explanation to Question 17. Tropical ‘A’ climates tend to be consistently
mild, with little change in average monthly temperature. Precipitation can vary month-to-month, but still
occurs year-round.
With such mildness and constancy, greater temperature change can occur from night to day than across the
entire year’s monthly averages.
21. Spraying water on green plants can help prevent frost damage because freezing water makes heat
available for absorption by nearby objects.
True ___
False ___
Note to Question 21: Compare to Questions 5 and 50. Liquid water contains a great deal of heat energy.
Some of that energy must be surrendered or released in order for liquid to convert to solid ice. Nearby
objects may absorb some of that released energy when liquid goes to ice.
A green leaf may escape freezing by absorbing water that releases heat as it freezes.
22. Which of the following statements is/are true of hurricanes and tornadoes?
a. Hurricanes at the Equator rely on vast amounts of warm, humid tropical air.
b. Hurricanes and tornadoes at the Equator are strengthened by the presence of Coriolis force and
masses of adjacent cold/dry air.
c. Tornado winds are based on Coriolis effect that deflects wind in circles to the right.
d. Tornado season peaks after hurricane season because dry land takes a long time to warm up each
spring, whereas ocean waters hold vast thermal energy all year.
e. None of the above statements is true.
Note to Question 22: There are no hurricanes at the Equator. Hurricanes derive energy from tropical
regions, but they form somewhere further north or south where Coriolis force and/or collision with colder,
drier air result in more severe winds.
Coriolis force turns winds to the right in descending air. In converging air, such as in a mid-latitude cyclone,
Coriolis force and convergence result in counter-clockwise winds. Tornadoes in the northern hemisphere
almost always turn counter-clockwise, just as mid-latitude cyclones do.
Tornado season in the USA peaks before the hurricane season, because oceans take longer to absorb energy
for storms. In contrast, tornadoes are common in spring-time over land masses where cold, dry air is still
available to clash with masses of warm, humid air that arrive from the ocean.
In fact, by late Summer, tornado season is winding down because there is no longer any cold, dry air
available to clash with warm, humid air. Meanwhile, hurricane season is peaking because the ocean has
warmed enough to supply energy needed for high-speed winds and heavy precipitation.
So, none of the statements above are true.
23. Each year, the amount of carbon dioxide in the atmosphere rises and falls because:
a. the northern hemisphere produces more greenhouse gas during summer.
b. southern latitude growing seasons dominate world atmospheric carbon dioxide absorption by
growing plants.
c. equatorial latitudes consume (absorb) much more atmospheric carbon dioxide during summer
than during winter.
d. northern hemisphere land masses vary widely in seasonal absorption of carbon gases
e. None of the above are true.
Note to Question 23: Equatorial regions vary little in how much oxides are absorbed by green plants.
Southern latitude land masses are too small to add or subtract greatly to swings in carbon oxides in the air.
The vastly larger land masses in the northern hemisphere account for most of the annual swing in carbon
gases in Earth’s atmosphere: during the summer growing season, northern hemisphere green plants absorb
vastly more carbon gases than they do during winter.
24. Atmospheric ozone ___________.
a. does not cause health problems for humans, plants and animals.
b. is produced by automobile exhaust interacting with sunshine.
c. is a serious air quality problem during the “inversion season” that begins in Salt Lake valley on
November 1 each year.
d. Answers ‘b’ and ‘c’ above are both true.
e. All of the above are true.
Note to Question 24: Ozone is hazardous to human health. However, atmospheric ozone is produced by
nature at high altitude where people rarely go. So, atmospheric ozone is not a health concern for people,
plants or animals.
Instead, ground-level ozone is a health hazard, caused by heat and solar energy interacting with air pollution
near the surface of the Earth. Ground-level ozone is primarily a summer time problem, when lots of
sunshine and high air temperatures combine with sulfur and nitrogen air pollution to produce more ozone
than is good for human health.
It is true that during winter, inversion conditions can trap air pollution. However, without heat and sunshine
during winter, relatively little ground-level ozone is produced.
Soot and aerosols are more of a problem during inversions, and inversions occur most often during colder
weather when lack of daily surface heating allows cold air to collect near the surface. Lack of air movement
allows air pollution to accumulate.
25. Which climate zone is most likely to exhibit average daily temperature variation greater than
annual temperature range?
a. BSk
b. Af
c. Cfa and Cfc
d. Cfa and Csa
e. All Df climates and Cfa
Note to Question 25: Tropical (A) climates near the Equator tend to be mild and very similar year-round.
Seasonal differences are very small, so average monthly temperatures are almost the same all year.
In fact, daily temperature change from morning to night can be greater every day than the difference between
the coldest month and the warmest month.
26. Which of the following best describes the diameter of the Earth?
a. 24,000 times π
b. 7,923 divided by 3.1415
c. C times π
d. 24,800 divided by 7,900
e. Circumference divided by π
Note to Question 26: Diameter (D) is the distance through the center, not the circumference, which is the
distance around the outside or perimeter.
So, D = C/ π. Likewise C = D * π.
Earth’s circumference is about 24,900 miles. The number π is a constant that represents the ratio between C
and D.
So, Earth’s diameter is roughly 7,900 miles, based on 24,900 divided by 3.141.
27. Based on class discussion, which of the following represents the highest absolute humidity?
a. 7/10
b. 6/8
c. 1/5
d. 2/4
e. 5/5
Note to Question 27: Absolute humidity is a measure of how much water is in the air as vapor. Absolute
humidity is not a measure of how much water could be in the air, just how much water is in the air. Absolute
humidity is only a measure of weight or mass of water that is actually suspended in a parcel of air at any
moment.
A ratio of 5/5 means that a parcel of air is full to capacity. The absolute amount of water in the air is 5 units,
and the vapor capacity of the air is also 5 units. Vapor saturation has occurred and no more water can be
added.
Warmer air can hold more moisture, so if air temperature rises, then a ratio of 5/10 might occur. The same
absolute amount of water is the same at 5 units, but the capacity for holding water has increased to 10.
All of the examples above represent relative humidity, a comparison or ratio between the actual, absolute
amount of water in the air and capacity. The numerator is actual water as absolute humidity, and the
denominator represents capacity.
In the case of 5/5, the air is cool enough that 5 units of water cause vapor saturation – no more water can be
added. With an increase in temperature, relative humidity goes down to 50%, because the air is holding the
same absolute humidity of 5, but could hold 10 – 5/10 = 50%.
The correct answer above is in option showing the largest numerator, the largest amount of actual water
(absolute humidity) in the air. The fractions are not important in this question. We only want to know which
option above represents the largest amount of actual water in the air, not a comparison between actual and
capacity, which would be relative humidity.
28. Ice releases heat during evaporation, and vapor releases heat when it condenses into liquid.
True ___
False ___
Note to Question 28: The first statement above is false: evaporation is the process of absorbing heat, which
makes substances feel cooler. Evaporation is conversion of heat we can feel into a chemical structure that
keeps water molecules separated by kinetic motion or vibration.
Evaporation is the process of absorbing enough heat for kinetic motion to break cohesion bonds that would
have held water as liquid. So, evaporation is a cooling process as water absorbs heat and converts it to a
different chemical state. Latent, or hidden heat is energy that is busy holding water molecules apart from
each other. During that state, we no longer feel that heat. Instead; surrounding air is cooler after evaporation
has converted that heat into a chemical state that keeps water vaporized.
The second statement in Question 28 is true: when vapor returns to liquid state, heat is released into a form
we can feel once again as a rise in temperature. When water returns to a liquid state, energy is no longer
keeping water molecules from re-attaching by cohesion into the water state.
29. The chemical quality of water supports which of the following statements?
a. Icebergs will raise ocean levels when they melt.
b. Fog tends to form in humid air when night-time radiation warms the ground.
c. When water boils, covalent bonds are broken and hydrogen separates from oxygen
d. Solid icebergs are less dense than surrounding water.
e. Steam fog requires temperatures at least 212 F.
Note to Question 29: All of the optional answers in Question 29 involve differences in the amount of
energy held by water as either ice, liquid or vapor.
Ice floats only because it is in a chemical arrangement that is less dense than liquid. Melting eliminates that
density difference so there is no longer a “tip of the iceberg”. Icebergs are already in the water, so no change
in sea level occurs when they melt.
However, if ice on land slides into the ocean, then sea level should rise because more water has been added.
Fog is just liquid water in the air that we can see. At night, radiation of energy from land or water goes back
into the atmosphere or to outer space, resulting in surface cooling. If enough cooling occurs, then kinetic
motion in vaporized water slows down and cohesion bonds re-attach one water molecule to another, creating
“sticky” liquid instead of free-floating vapor.
Weak cohesion bonds that hold separate water molecules together are easily broken by simply adding heat
enough to cause molecules to vibrate apart. Liquid water that was a little bit “sticky” by cohesion at lower
temperature becomes vaporized into individual free-floating molecules that are too energetic to remain
connected.
However, keep in mind that inside each individual molecule, strong covalent bonds keep oxygen and
hydrogen atoms from separating. So, water is still water no matter whether it is in liquid or vapor form:
hydrogen and oxygen are still bonded by strong covalence inside each individual molecule even if outside
cohesion bonds no longer weakly connect one molecule to another.
Steam is the same thing as fog and/or clouds in the sky. Fog is water in the air that has lost enough kinetic
motion or vibration to become visible as condensed liquid rather than invisible vapor. Condensation occurs
whenever evaporated water cools enough to no longer prevent cohesion bonds from re-attaching one water
molecule to another.
So, a boiling pot on the stove has heated water enough to break cohesion bonds, allowing liquid to go to
vapor. Directly above the boiling pot is air cool enough to return vapor back to liquid as kinetic motion is
lost due to cooling. Clouds of steam above a boiling pot represent vaporized water that is returning to liquid
form by cooling enough to reattach by cohesion.
Steam fog can occur at any temperature where air is cool enough that lack of kinetic motion allows
molecules to reattach by cohesion. Condensation is water with not enough heat and kinetic motion to
prevent cohesion bonds from forming a liquid out of vapor. So, exhaling warm breath from your lungs into
cold winter air will cause enough cooling for warm vapor to condense back into cool liquid that we can see
as a cloud.
30. In the northern hemisphere, a location near the ocean will usually have a climograph with a
relatively steep annual temperature curve.
True ___
False ___
Note to Question 30: Closeness to oceans and large lakes tends to promote mildness because water can
hold much more energy than can dry land. Dry land will radiate heat back into the atmosphere much more
quickly than will water, so temperatures rise and fall more quickly over land than over water.
A climograph for coastal locations will tend to relatively less variation in monthly average temperature. In
fact, daily temperature swings are also much less variable at the coast than inland.
31. Mid-latitude cyclones are common in the United States. An occluded front has at least one thing in
common with a “dirty air” inversion: air aloft is temporarily warmer than at the surface.
True ___
False ___
Note to Question 31: At the conclusion of a mid-latitude cyclone, warmer air has finished lifting over
colder air. That brief condition is similar to an air “inversion” because air aloft is temporarily warmer than
air at the surface. The presence of air pollution is not a factor common to both occluded fronts and stagnant
air inversions.
An occluded storm front quickly gives way to more normal conditions wherein daily solar warming results in
unstable conditions and rising air.
32. Atmospheric ozone:
a. is air pollution produced by chlorofluorocarbons (CFCs)
b. helps keep the surface of the Earth warmer than otherwise.
c. is corrosive, poisonous and noxious.
d. b and c above are true.
e. a and c above are true.
Note to Question 32: Noxious ozone is produced by nature and by air pollution interacting with sunlight
and heat. CFC chemicals tend to break down ozone into useless chlorine monoxide. Atmospheric ozone (in
the ozone layer) blocks ultraviolet energy from reaching Earth’s surface where it would tend to convert to
heat.
33. Utah is dominated by which two climate zones?
a. D and BWk
b. BSk and H
c. Cf and Df
d. H and BWh
e. A and C, with some E
Note to Question 33: A world map of climates shows that the U.S. southwest is dominated by true hot
deserts (BWh) that give way to cooler steppe grasslands (BS) and mountain (H) climates moving northward.
Utah has more grass and shrub (BS) and mountain landscapes (H) than true desert (BW). Cold winters (k)
occur almost everywhere in Utah.
34. The coastal United States exhibits at least two kinds of ‘B’ climate and at least three kinds of ‘C’
climate.
True ___
False ___
Note to Question 34: The United States is a microcosm of most world climates and hosts even more than a
proportionate share of desert and/or dry climates. However, U.S. coastal conditions result in mild ‘C’ and/or
severe ‘D’ climates rather than ‘B’ climates.
35. In a general way, the change in climate resulting from moving thousands of miles closer to the
Equator may also be accomplished by going downhill toward seal level several thousand feet.
True ___
False ___
Note to Question 35: “Mr. Allred’s Rules” are a summary of key points across several chapters in the
textbook. Weather and climate tend to be more severe with increasing distance from the Equator and/or
increasing distance from sea level. Therefore, moving closer to sea level and/or closer to the Equator should
result in milder conditins.
Notice that weather and climate change quickly with a change of only a few thousand feet in elevation.
Substantial climate differences between latitudes emerge only by changes across hundreds or even thousands
of miles.
36. Hurricanes help transfer energy from equatorial regions and help prevent drought in many subtropical areas, including Florida.
True ___
False ___
Note to Question 36: Both statements are true.
37. Which of the following tends to reduce the amount of solar energy that reaches Earth’s surface:
a. long-term restrictions on CFC production and use.
b. collision between solar ultraviolet energy and atmospheric oxygen at high altitude.
c. dust and other aerosols in the atmosphere.
d. All of the above
e. None of the above
Note to Question 37: Some man-made CFC chemicals have been found to destroy high-altitude
atmospheric ozone. Without atmospheric ozone, most ultra-violet solar energy would reach Earth’s surface.
Removal of CFC chemicals from the atmosphere is expected to result in gradually increasing atmospheric
ozone that should tend to reduce ultraviolet energy reaching Earth’s surface.
Dust and aerosols also block ultraviolet energy by reflecting it back into outer space.
38. A weather pattern that mixes ‘cT’ and/or ‘cP’ air masses with an ‘mT’ air mass is most likely to
produce ________.
a. mild, sunny weather that dominates much of Mexico and other dry sub-tropics
b. some of the world’s most severe weather.
c. a mid-latitude anti-cyclone
d. high-speed jet stream flow
e. All of the above except ‘a’
Note to Question 38: Mid-latitude cyclones exhibit some of the world’s most severe weather, including
tornadoes, squall lines and “super cells. Aside from Coriolis force that grows stronger with latitude, severe
storms also rely the accelerated lifting and high winds that result from collision between air masses that
differ greatly in temperature and/or humidity.
‘cT’ and ‘cP’ air masses tend to be dry; ‘mT’ tends to be warm and humid. Collisions tend to promote highspeed winds and heavy precipitation.
39. Which of the following lines are part of “Great Circles” of the Earth?
a. the tropics of Cancer and Capricorn.
b. any line of latitude.
c. a typical, unadjusted time zone boundary.
d. the Arctic Circle (or Antarctic Circle).
e. All of the above
Note to Question 39: A “great circle” is any straight line drawn on the surface of the Earth that, if
continued all the way around would bisect the Earth into two equal parts.
Time zones run from pole to pole and would bisect the Earth if added to the corresponding time zone on the
opposite side of the Earth 12 hours away. For practical reasons, many time zone boundaries jog or shift a bit,
but still represent 15 degrees of longitude, or one hour of Earth rotation.
Except for the Equator, lines of latitude are not great circles because they do not bisect the Earth.
40. The inter-tropical convergence zone (ITCZ) is related to:
a. Masses of rising air and precipitation in areas within about five degrees north and south latitude.
b. Year-round rain in most tropical regions.
c. Alternating periods of drought or flooding at latitudes just higher than reached by the ITCZ.
d. All of the above
e. None of the above
Note to Question 40: All of the above are true. See also Question 41 below.
41. Which of the following is (are) true of monsoon conditions:
a. The ITCZ undulates north and south, following the Sun’s relative position in the sky.
b. If the ITCZ is not far enough north in June, places like India will probably experience drought.
c. Utah and Arizona can receive a bit of ‘monsoon’ effect when the ITCZ rises northward during
our longest days of the year.
d. In the northern hemisphere, the south end of Hadley cells will tend to be rainy.
e. All of the above are true.
Note to Question 41: See also Question 40 above. Monsoon means seasonal shift in wind direction. In
most cases, changes in wind direction also result in either a dry season or a rainy season. The ITCZ tends to
center where the Sun is directly overhead at noon, and is closely associated with rain and clouds.
Even Utah and Arizona can have a mild summer monsoon rainy season when the ITCZ is at its furthest north
in summer.
The equator-ward side of Hadley cell flow is associated with rain, and the pole-ward side is associated with
dryness. Arizona and Utah are closest to the dry, poleward side of Hadley cell flow.
India is in the northern hemisphere, so a strong northward drift of the ITCZ is needed for India to receive
enough rainfall for good farming.
42. A weather map showing a steep pressure gradient generally indicates high pressure, calm weather
and fair skies.
True ___
False ___
Note to Question 42: See also Question 44 below. A steep gradient is shown on a map as closely spaced
isolines and results in windy conditions that are obviously not calm, but can be sunny; however, most often,
wind is also associated with clouds, precipitation and wind.
43. A map of sunny, mild weather is more likely to show widely spaced isobars and no isohyets.
True ___
False ___
Note to Question 43: See also Question 44 below. Widely spaced isolines for wind (bars) indicates little
windiness. Isohyets are about precipitation, and there won’t be any such isolines for sunny, mild weather.
44. A map of closely spaced isobars in concentric circles and a pressure reading of 900mb in the center
most likely indicates _________________.
a. a tornado
b. the center of an eye in an Indonesian typhoon
c. Both options above are consistent with the map description
d. Neither option above is reasonable
Note to Question 44: Closely spaced isolines of any kind indicate relatively faster change across distance
and/or time. Closely spaced isobars (air pressure) suggest rapidly changing air pressure which always means
wind  air moving from higher pressure to lower pressure.
Concentric circles of isobars indicate a cell or center of either higher or lower pressure. Closely spaced
isobars with a center at more than 100mb lower than normal indicates rapidly rising air that is being replaced
by high-speed wind moving in toward the center. Severe storms almost always exhibit high-speed wind, and
cyclonic storms tend to have a center of much lower air pressure than elsewhere.
In a very large storm, the center “eye” tends to exhibit much higher air pressure, clear of clouds and not
windy. In the adjacent, surrounding eye wall wind speeds are at their highest in the storm.
45. A weather inversion will exhibit:
a.
b.
c.
d.
e.
mountain air temperature warmer than valley air.
poor air quality in valleys.
little chance of precipitation.
All of the above
None of the above
Note to Question 45: Normally, atmosphere warms from the surface upward, so air temperatures decline
inversely with altitude. Daily solar warming causes air to rise and circulate, which helps disperse air
pollution.
When there is not enough wind or solar warming, denser air may collect in valleys, resulting in concentrated
air pollution over time. In winter, air may be cooler at the surface than aloft, an “inverted” condition.
Air that is stable, instead of rising, is less likely to promote lifting by condensation that could produce
precipitation. Inversion conditions tend to be associated with dryness and poor air quality.
46. Inside your house, which of the following effects is likely?
a. Air touching the glass can cool by conduction and then flow downward by convection to the
floor.
b. Radiation from inside the house can pass through a glass window, causing a loss of energy to the
outdoors.
c. During the day, solar energy can radiate inward through the glass and be absorbed by solid
objects on the inside.
d. Solar energy can reflect off a glass window and back into outer space.
e. All of the above are true
Note to Question 46: Air that touches cold glass can lose heat to the glass by direct contact or conduction.
Less kinetic motion means denser and heavier air that sinks toward the floor by convection and then flows
along the floor by advection. Radiation can go through the glass in both directions, so that indoor space can
gain or lose heat. Like the Earth’s atmosphere, glass reflects some energy back into space while some
energy passes through to become heat after absorption.
47. A span of 85 degrees of longitude represents:
a. Less than six time zones.
b. About eight time zones at the Equator, and about 12 times at halfway to the poles
c. About 1/3 of a full day of Earth rotation.
d. At least 10 hours of Earth rotation, considering convergence of longitude lines near the poles.
e. Answers ‘b’ and ‘d’ above are both correct.
Note to Question 47: With 360º in a circle and 24 hours in a day, each hourly time zone contains 15º of
longitude at any latitude. So, six time zones would represent 90º of rotation or about six hours of time. That
would be true at all latitudes, so answer ‘b’ is not reasonable. Convergence of time zones toward the poles
does not change the fact that there are still 360º in a circle and 24 hours in a day, no matter how far we are
from the Equator. .
48. Cfa climate conditions provide year-round moisture, allowing citrus crops to thrive at higher
latitude in humid eastern United States than in dry western states.
True ___
False ___
Note to Question 48: The ‘f’ climate sub-category does indicate year-round moisture that is helpful for
some growing plants; however, humid eastern U.S. states are also exposed to occasional invasion of cold,
dry air from Canada that can destroy sensitive plants.
A hard freeze that occurs only once in 10 years would not show up on a climograph that shows only average
weather across one year. So, Florida may have some genuine tropical ‘A’ climate but notice in the textbook
that it does not extend nearly as far north as the Csa and Csb climates in California where citrus is also
possible.
California weather is somewhat more protected from hard freezing because of mild coastal conditions nearby
and high mountains to the east that help keep out invasions of icy air. So, the safe zone for citrus actually
reaches higher latitude in California than in Florida.
California may not be ideal for citrus, but it is more consistent than Florida’s tropical climate that is
occasionally frozen. Having year-round moisture is nice for farming, but can’t make up for periodic ice and
snow that can kill everything.
49. Which of the following is not related to long-term climate change?
a. Changes in Earth’s obliquity and plane of the ecliptic
b. Solar wind and sunspots
c. Earthquakes and volcanoes
d. Positive feedback mechanisms
e. The rate at which Earth turns on its axis
Note to Question 49: The number of hours in the day is not mentioned in the textbook as a factor in climate
change.
50. When water freezes to ice it releases energy, adding warmth to nearby objects. When liquids
vaporize, the air around them gets cooler.
True ___
False ___
Note to Question 50: Compare to Questions 5 and 21 above. When liquids absorb enough energy they can
evaporate (vaporize). That energy becomes hidden or latent, so air temperature is lower.