Geography 1700 – Natural Hazards
AJ Allred, Fall 2015
Student Name _____________________
Quiz 11
Explanations and Answers
Question 1
What is a good estimate of average, or normal daily air pressure at 10,000 feet altitude above sea
level?
10 pounds per square inch (psi)
1,013mb
20 psi
507mb
5 psi
Sea level air pressure tends to be a little less than 15 pounds per square inch (psi). At 18,000
feet, air pressure is commonly about half that at sea level, or a bit more than seven pounds per
square inch. In millibars, average sea level air pressure measures about 1,013mb, and about
507mb at 18,000 feet. 10,000 feet is in between those two elevations, and 10 psi is the only
alternative above that falls in that range.
a more accessible alternative to drag & drop reordering.
Question 2
If CFC chemicals had never been banned, then what would be the most likely trend among the
options listed below?
Slightly rising earth surface temperature and more frequent cases of human skin cancer.
Increasing ozone in the stratosphere.
The stratosphere would become much warmer.
Answers 'b' and 'c' above are both correct.
All of the above are true.
Man-made chlorofluorocarbons (CFCs) are known to destroy ozone in Earth’s stratosphere.
Ostensibly, loss of atmospheric ozone would allow powerful ultraviolet energy to pass through
the ‘ozone layer’ with likely health hazards for people and more energy available for absorption
in the troposphere. Without restrictions on CFC production and use, CFC molecules would
continue to degrade Earth’s ozone layer. Less ozone in the stratosphere would result in less
absorption of ultraviolet in that realm, with less conversion to longer wave, thermal radiation we
measure as heat.
more accessible alternative to drag & drop reordering.
Question 3
Atmospheric pressure varies negatively (inversely) with altitude.
True
False
Increasing altitude exhibits lower atmospheric pressure, an inverse or negative relationship. This
element is a more accessible alternative to drag & drop reordering.
Question 4
Cloud formation is associated with low and/or falling atmospheric pressure.
True
False
Rising air leaves less mass of air in the space it vacated. Less mass measures as lower pressure.
Rising air also tends to cool by decompression with altitude. At dew point temperature, clouds
form as invisible vapor condenses back into visible liquid water that may fall as precipitation.
This element is a more accessible alternative to drag & drop reordering.
Question 5
Stormy weather (wind, clouds and precipitation) is associated with high or rising atmospheric
pressure.
True
False
See question 4 above. High air pressure is associated with sinking air that presses outward
because it has greater mass than lower-pressure air. Sinking air tends to warm as it goes down.
Warming air is more able to evaporate water. So, with sinking air there is little basis for vapor to
condense back to liquid clouds we can see.is a more accessible alternative to drag & drop
reordering.
Question 6
In a frontal or 'wedge' storm, mountains like the Wasatch Front create rotating winds and very
high air pressure.
True
False
Frontal or wedge storms involved a mass of cooler, drier air driving underneath more buoyant,
lighter, wetter air. Rising wet air may cool to condensation level, converting vapor to liquid
clouds and liquid precipitation. Release of latent heat during condensation can cause rapid
lifting for more vigorous winds, lightning and even tornadic winds.
This element is a more accessible alternative to drag & drop reordering.
Question 7
Which of the following items is not one of the four major types of storms?
Frontal or wedge
Convective
Conductive
Convergent
Orographic or mountain
Conduction is the process of energy moving through solid substances, such as metal and water.
Convection represents moving air that carries energy with it. Convective storms involve humid,
warm air that rises easily. As air rises it decompresses and then cools. If air cools enough,
clouds will form as condensation level is reached. This element is a more accessible alternative
to drag & drop reordering.
Question 8
Coriolis force is associated with the world's most violent storms, including tornadoes and
hurricanes.
True
False
Coriolis force tends to be stronger with latitude, helping produce mid-latitude storms that include
rotation of winds around a low-pressure center. Vigorous lifting results from wedging of drier,
cooler air below warmer, wetter air. The result is potentially violent winds, heavy precipitation
and occasional formation of tornadoes. Hurricanes are also tornadic storms that form by
interaction between air masses and resulting rotation. Tornadoes and hurricanes do not form in
the tropics, due to lack of Coriolis force and insufficient contrast between air masses.
This element is a more accessible alternative to drag & drop reordering.
Question 9
Mid-latitude cyclones, including tornadoes, are ____________________.
associated with Coriolis force
most common in the tropics where solar energy is intense
associated with collision between two air masses that are both hot and humid
associated with equatorial regions that are dominated by water and solar energy
Answers 'b', 'c' and 'd' are correct.
By definition, mid-latitude cyclones occur in mid-latitudes, not the tropics. Colliding air masses
differ substantially in heat and water content. Coriolis force strengthens with increasing latitude
and is weak or non-existent at the Equator, so tornadic, cyclonic storms tend to not occur in
lower latitudes.
This element is a more accessible alternative to drag & drop reordering.
Question 10
Weather varies for many reasons. However, in general ways discussed in class, a year of morethan-usual precipitation in Utah is also more likely to __________________.
produce more tornadoes than usual.
be declared an "El Niño" year.
include vigorous mid-latitude cyclones
not be labeled a "La Niña" year
All of the above are true.
Humid air contains latent heat. Latent heat is positively associated with the strength and duration
of stormy conditions. In Utah, an El Niño may bring more-than-usual precipitation. Water
vapor holds vast energy that can help sustain and/or strengthen a storm.
This element is a more accessible alternative to drag & drop reordering.
Question 11
A tropical depression exhibits _________________.
low atmospheric pressure
lower-than-usual ocean level
calm air, with no wind
clear skies and stable, unchanging air pressure
All of the above.
Atmospheric depression means that air pressure readings are relatively lower than surrounding
air, so wind blows toward the depression. Lower air pressure means that there is less weight of
air over ocean, so ocean level or “sea level” tends to rise, contributing to storm surge when
storms reach land. Falling air pressure means that air pressure readings or numbers are falling,
not the air itself. In fact, with lower air pressure, air tends to be rising, attracting incoming winds
that can be vigorous, even hazardous.
This element is a more accessible alternative to drag & drop reordering.
Question 12
Storm surge includes everything above except ______________.
high wind speed
heavy precipitation
high waves
potential for property damage
high atmospheric pressure
High air pressure is associated with relatively dry air that is heavier than humid air. High
pressure may be warm or cold, but is often cold because cold air is more dense. High air
pressure, associated with sinking air, tends to warm by compression as it sinks.element is a more
accessible alternative to drag & drop reordering.
Question 13
When a mid-latitude cyclone encounters a mass of cold air, the storm will immediately stop for
lack of energy.
True
False
In general, warm, humid air will tend to rise more vigorously when adjacent air is cooler and/or
drier. Eventually, cooler air will tend to absorb heat from adjacent warmer air and a storm may
diminish for lack of energy.
s element is a more accessible alternative to drag & drop reordering.
Question 14
The majority of Earth's atmosphere is made up of ______________.
Oxygen
Carbon dioxide, monoxide, and oxides of nitrogen and sulfur
Nitrogen
Ozone
None of the above.
About 79% of Earth’s atmosphere is molecular nitrogen, with two nitrogen atoms. Oxygen
makes up about 20%. Oxides and other substances comprise less than one percent of Earth’s
atmosphere.
This element is a more accessible alternative to drag & drop reordering.
Question 15
In the troposphere, atmospheric pressure and atmospheric temperature vary positively with each
other most of the time.
True
False
Air pressure is lower with altitude, and temperature is lower with altitude. This element is a
more accessible alternative to drag & drop reordering.
Question 16
A weather inversion is ______________.
likely to include colder-than-usual air temperature in the stratosphere and mesosphere
warmer- than-average air temperature in the stratosphere
relatively warm air at the surface, and colder air aloft
relatively colder air at the surface than aloft
All of the above can occur when inversions are in place.
Earth atmosphere is generally warmer near the surface, because more mass is available for
absorbing energy, and because of heat in dirt and water. So, the atmosphere tends to be unstable,
as daily warming leads to rising air. The Earth heats form the bottom up each day.
An inversion exhibits relatively cooler air near the surface and relatively warmer air aloft.
Colder air is unlikely to rise, and warm air is unlikely to sink, so stagnation develops and surface
air pollution accumulates for lack of circulation.
The stratosphere and mesosphere are not associated with the weather turbulence and circulation
that are generally confined to the troposphere. Conditions tend to be stable.s element is a more
accessible alternative to drag & drop reordering.
Question 17
Latent heat increases when ______________.
water vapor condenses back to liquid
liquid water evaporates
air rises rapidly into a region of lower air pressure
water freezes
None of the above has anything to do with latent heat.
Evaporation of liquid into vapor requires energy, so energy is absorbed by water during
evaporation. Absorbed energy becomes latent, or hidden in water vapor that is also invisible.
Condensation is the opposite of evaporation, releasing latent heat back to heat we can feel and
vapor back to liquid we can see.
Rising air decompresses as it rises into lower pressure aloft. Decompression causes cooling by
dispersing energy in air, dilution. Cooling by decompression reduces the ability of air to hold
moisture, so at dew point temperature latent heat is released as vapor condenses back to liquid.
Clouds form as latent heat is released, and water becomes visible as liquid once again.
element is a more accessible alternative to drag & drop reordering.
Question 18
Northern hemisphere monsoon conditions are most closely associated with
_______________________.
the ITCZ moving closer to the Tropic of Cancer
the ITCZ moving closer to the Tropic of Capricorn
periods when the United States experiences its shortest days and longest nights
drought in India
sunny and dry weather in southern Utah
Monsoon refers to seasonal shift in wind patterns. Typically, the result is also a rainy season or a
dry season. In the northern hemisphere, the ITCZ will tend to move northward with the Sun’s
vertical position in the sky. The result is on-shore winds in places like India and a distinct rainy
season. Southern Utah, though far from the Equator and the ITCZ, also receives some additional
summertime thunderstorms because the ITCZ is closer during summer.
The Sun is never directly overhead any further north than the Tropic of Cancer.
cessible alternative to drag & drop reordering.
Question 19
Clouds tend to form when sinking air is heated by compression in a high pressure ("H")
situation.
True
False
Air becomes warmer by compression (concentration) as it sinks to lower altitude. Warmer air
has greater capacity to hold moisture. So, sinking air is associated with high pressure and
dryness. Sinking air warms and becomes more “thirsty” as it nears the surface, so high-pressure
weather is associated with evaporation, not condensation.
There is no reason for clouds to form (condensation at dew point temperature) during highpressure weather when air is sinking toward the surface, warming and compressing as it goes.
Instead, cloud formation and storms (rain, wind) is more likely when air is rising,
decompressing, cooling and then releasing latent heat and water back to clouds. .is a more
accessible alternative to drag & drop reordering.
Question 20
Coriolis force causes ________________.
descending air to turn clockwise in the northern hemisphere
descending air to turn counter-clockwise in the northern hemisphere
rising air to become warmer as it compresses at higher altitude
tornadoes and hurricanes at the Equator
mid-latitude cyclones at the Equator
As demonstrated on a model globe in the classroom, in the northern hemisphere winds tend to
turn to the right, as viewed from above. Sinking air is pushing outward from the center of a
high-pressure cell, so it is deflected to the right. Sinking air means higher pressure, as mass of
air presses down on the surface. High-pressure air is associated with dry weather, and even
weather inversions when cold air is trapped at the surface.
In contrast, rising air is moving toward a low-pressure center. Coriolis force to the right is
counter-acted by gradient force of incoming air, which results in winds in low-pressure cells
turning to the left, or counter-clockwise.
Rising air tends to decompress with lower pressure at higher altitude.
Tornadoes, hurricanes and mid-latitude cyclones are not associated with the tropics, due to lack
of:
- contrasting air masses
- lack of general Coriolis effect.