GLOBAL CHANGE:
GEOL 1060
An Earth Science Perspective
Fall 2002
MidTerm
Name ______________________________
Student Number ______________________
Carefully read each question; be certain you know what is being asked.
True/False (Please spell out)
1) _______
2 pts each
The Pacific Ocean is on average saltier than the Atlantic Ocean.
2) ________ Deserts occur at the equator because that's where the greatest amount of solar radiation
is
received.
3) ________
Over 75% of the world’s fresh water is stored in groundwater.
4) ________ Surface currents in the ocean move on average about 90 degrees off the prevailing
wind
direction.
5) ________
Earthquakes and volcanos have the same primary forcing.
6) ________
Nitrogen is an important greenhouse gas in Earth’s atmosphere
7) ________
The boundary between the stratosphere and the troposphere is called the tropopause.
8) ________
Relative humidity is nearly constant across the globe.
9) ________
The latent heat of condensation is greater than the latent heat of freezing.
10) ________ Solar radiation is concentrated at shorter wavelengths than is radiation emitted from
Earth.
11) ________ Thermohaline circulation is restricted to the Atlantic Ocean
12) ________ Summer in the Northern Hemisphere occurs when Earth is closest to the Sun.
13) ________ Hot spots are always associated with fluid volcanism.
14) ________ Almost all of the solar radiation that reaches the top of Earth’s atmosphere makes it
through the atmosphere to the surface of the Earth.
15) _________ During a magnetic reversal, the Earth’s spin slows down then reverses the direction of
spin, causing the magnetic field to change its orientation.
16) ________ Typical plate movements are roughly 5 to 10 kilometers per year.
17) ________ Because gases can be selective absorbers, they are all greenhouse gases.
18) ________ There was a very large greenhouse effect in Earth’s atmosphere even before human
activity introduced large amounts of greenhouse gases to the atmosphere.
19) ________ Volcanism commonly occurs along transform plate margins.
Multiple choice
Select the BEST answer to each question
3 pts each
20) Stripes of rocks with alternating normal and reversed orientation of their magnetic minerals found
on either side of the Mid-Alantic Ridge are evidence for:
a) subduction
b) downwelling
c) feedback
d) sea-floor spreading
e) transpiration
21) Primary productivity is the fixation of inorganic carbon from the medium in which an organism
lives (atmosphere, ocean, etc.) into organic carbon. The process by which they do this is called:
a) transpiration
b) photosynthesis
c) downwelling
d) emission
e) homeostasis
22.) A seasonal reversal of the prevailing winds is known as
a) Hadley Cell
b) Monsoon
c) Ferrel Cell
d) Convection
e) Coriolis Effect
23) New oceanic crust is formed along
a) mid-ocean ridge
b) subduction zones
c) transform plate margins
d) faults
e) convergence zones
24) The primary forcing for plate tectonics is:
a)
b)
c)
d)
e)
Coriolis Effect
Ekman Spiral
The rotation of the Earth
Gravity
Radioactive decay deep in Earth’s interior
25) The natural greenhouse effect is caused by:
a) Reflection of the sun’s radiation by clouds
b) Changes in albedo causing positive feedback
c) Gases in the atmosphere absorbing long wave radiation from Earth
d) Changes in the climate in the last 4000 years
e) Differential heating of the oceans and continents.
26) A phenomenon that causes moving objects in the northern hemisphere to veer to the right is:
a) Republican Party
b) Democratic Party
c) Coriolis Effect
d) Elvis
e) Dr. Spock
27) You are skiing in the same area of the backcountry every weekend for many weeks during a snowy
winter. Each time you cross a particular treeless slope you notice that the snow depth has increased
from the previous trip. One snowy day, as you are skiing toward the slope, it slides away as an
avalanche just before you arrive. This is an example of:
a) random changes in nature
b) positive feedback
c) negative feedback
d) threshold
e) homeostasis
28) Which of the following is not true about hurricanes?
a)
b)
c)
d)
e)
They commonly originate at the equator.
They originate in areas of warm surface waters (usually above 26 °C)
They usually begin as a low pressure system
Wind speeds increase in part due to the release of latent heat high in the rising air column
They require the air to rotate
29) Which of the following does not occur at subduction zones?
a) Oceanic crust is created
b) Earthquakes
c) Volcanism
d) Oceanic crust is reincorporated back into the mantle
Short Answer Questions
want to know why.
Keep the answers short, but do make them complete. In most cases, we
5 pts each
31) Sea-floor spreading occurs at a constant rate. On the ocean floor, alternating stripes of normal and
reversed polarity on either side of the spreading center are not all of equal width (see figure above).
What does this tell you about the length of time the Earth spends in periods of normal and reversed
polarity? Justify your answer.
32) You are thinking of taking a vacation to Hawaii, but you hear on the news that Mauna Loa, the
large volcano on Hawaii, is expected to have a major eruption at about the same time as you plan to
arrive for your vacation. Would you change your plans? Justify your answer.
sinking
sinking
upwelling
upwelling
warm
surface
current
cold
deep
current
The figure above shows oceanic thermohaline circulation. Answer the following questions.
33) Sinking of surface waters occurs in the northernmost North Atlantic. What are the two
3
pt mechanisms that cause the surface waters to increase in density in this area sufficiently that they
sink?
34) The average residence time of a water molecule in the deepwater of the thermohaline
pt circulation (the time between initial sinking and upwelling) is about :
a)
b)
c)
d)
e)
a few years
a few hundred years
a few thousand years
tens of thousands of years
millions of years
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