Download 2011 Final Exam

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MEA 214 FUNDAMENTALS OF METEOROLOGY II
Spring 2011 Final Exam
1.) True/False regarding cloud and precipitation formation:
___ a.) Clouds consist of water vapor.
___ b.) In some situations, clouds can form without rising air motion.
___ c.) Clouds with temperatures below freezing are usually composed entirely of ice
crystals.
___ d.) Cloud seeding requires the presence of supercooled liquid water droplets.
___ e.) Snow only forms from the Bergeron process, while the formation of rain only
involves the collision coalescence process.
___ f.) Cirrus clouds are made up of mostly supercooled liquid water, despite the cold
temperatures at which they occur.
___ 2.) As we’ve seen this semester, low-pressure systems, as analyzed using sea level
pressure, are often associated with bands of cloud and precipitation. Which of the
following are factors that contribute to precipitation in lows pressure systems?
a.) The involvement of friction in the force balance near earth’s surface results in flow
towards lower pressure; the result is that lows are regions of convergence near the
surface, which is associated with rising air.
b.) Low-pressure systems often form due to the presence of an upper-level disturbance
centered to the west of the surface low; upper-air disturbances are accompanied by
rising air to their east, helping the low to form in the first place.
c.) Low pressure areas are accompanied by fronts, which focus the ascent into narrow
bands as lifting takes place in the vicinity of the frontal boundaries.
d.) All of the above.
3.) Consider the 500-mb height map below at left, and the corresponding isotach cross
section at right. The orientation of the section is shown as a dashed line on the 500-mb
map. In the 4 blank locations on the cross section, indicate whether the temperature
would be warmer or colder relative to the other temperature at that altitude.
_______
_______
_______
_______
___ 4.) Which of the following best explains why the horizontal pressure gradient force
(PGF) typically increases with height throughout the troposphere, reaching maximum
values in the vicinity of the tropopause?
a.) Because air density decreases with height, the PGF actually decreases with height.
b.) With stronger wind speeds aloft, a stronger Coriolis force is present. This requires
a strong horizontal pressure gradient to keep the flow in balance.
c.) Pressure decreases more rapidly with height in cold air than in warm air; the
farther up you go, the greater the accumulated difference in pressure (or height).
d.) Because the density of air decreases with height, the pressure gradient force
increases with height- the PGF is inversely proportional to density.
5.) On Wednesday, 27 April 2011, supercell thunderstorms spawned tornadoes across the
deep south, with the state of Alabama experiencing the worst impacts. The map below at
left shows the GFS-model sea level pressure and surface temperature analysis for 18
UTC on the 27th. At right, the sea level pressure and mosaic radar reflectivity are shown
for 22 UTC on the 27th.
Severe storms
a.) Based on the available data, sketch the approximate location of any important fronts,
using correct symbols, on the map at left.
___ b.) Which of the following best characterizes the location of the severe weather
relative to the fronts you drew in a.)?
(i) The severe storms were located in advance of a cold front.
(ii) The severe storms were located in advance of a warm front.
(iii) The severe storms were associated with an occluded front.
6.) Match the temperature cross-sections at right to the corresponding frontal type:
(a)
(b)
(c)
___ (i) Occluded
___ (ii) Warm
___ (iii) Cold
7.) Cyclone/anticyclone true/false:
___ a.) In order for the surface pressure to increase with time in a high-pressure system, a
net convergence of air must occur in the overlying air column.
___ b.) Cyclones exhibit clockwise rotation in the Southern Hemisphere.
___ c.) Low pressure systems tend to form to the east of upper-level troughs.
___ d.) Most major tornado outbreaks are associated with synoptic-scale weather systems
such as cyclones or fronts.
8.) What is a typical (average) horizontal size of each of the following weather systems?
In answering this question, consider the approximate diameter of the main circulation of
the system in the lower troposphere. Select answers to the nearest order of magnitude
(e.g., 10000, 1000, 100, 10, 1, .1 km, etc).
a.) Mid-latitude cyclone: __________ km
b.) Supercell thunderstorm: ___________ km
c.) Tornado: ____________ km
d.) Hurricane: _____________ km
____ 9.) One day you observe thickening cirrostratus clouds in the morning, followed by
altostratus clouds in the afternoon, and finally a steady, light rain by evening.
The next morning the rain has ended, and it is clear. The temperature is about the
same as the day before. A northwesterly wind has replaced the southeasterly
winds of the previous day. What type of front was most likely passing through?
a.) stationary front
b.) warm front
c.) cold front
d.) occluded front
___ 10.) Why do cyclones tend to form in the lee (to the east) of the Rockies?
a.) The enhanced temperature contrast there leads to frequent cyclone formation.
b.) The presence of the Rockies allows warm, moist air to stream northward from
the Gulf of Mexico, favoring cyclogenesis.
c.) Air columns are stretched as they pass to the lee of the Rockies, spinning up
vorticity (cyclones).
d.) “Self development” is favored to the east of major mountain barriers due to the
combination of strong temperature contrasts and moisture availability.
___ 11.) Which of the following best explains why the U.S. East Coast is a favorable
location for cyclones to form?
a.) The waters offshore have less surface roughness and therefore less friction,
making the region favorable for storms to spin up.
b.) The Appalachian Mountains help to cause cold-air damming; the low pressure
ridge associated with CAD is the start of a cyclone.
c.) Tropical systems moving in from the east turn north along the east coast,
leading to extratropical cyclones forming there.
d.) There is often a strong horizontal temperature gradient along the coast due to
the contrast between land and the warm Gulf Stream waters.
A
D
B
C
12.) The map above shows 500-mb height from a recent GFS model forecast. Use this
map to answer the following questions.
___ a.) Which point would most likely correspond to the location of a surface anticyclone?
___ b.) Which point would most likely correspond to the location of a surface cyclone?
___ c.) Which point would most likely have large 500-mb vorticity?
___ d.) Which point would be most likely to have divergence aloft?
13.) The map below shows 300-mb height contours, along with shaded isotachs. Several
jet streaks are evident. Considering only the jet streaks, which points would be likely to
exhibit divergence aloft, rising air, clouds, & precipitation? There may be more than
one correct choice; list all that would be expected to meet these conditions: ________
D
G
B
A
F
I
C
E
H
14.) For the surface observations shown below, (a) analyze the sea-level pressure with a
4-mb contour interval, starting with the 1012-mb contour, and (b) sketch the most likely
location of a frontal boundary.
123
099
082
080
072
077
037
067
080
____ 15.) The earth system is characterized by excess radiational heating in the tropics
and a deficit in the polar regions. Which of the following best describes the processes
that work to equalize the heating difference?
a.) The difference is mostly made up by ocean currents. Because water has such a large
heat capacity, it is a more efficient heat transporter than is the atmosphere.
b.) The atmosphere and oceans contribute roughly equally to the poleward heat transport
in midlatitudes.
c.) The atmosphere, with cyclones being a key element, is associated with greater
poleward heat transport than the oceans.
d.) This heat transport is largely accomplished by the atmospheric Hadley circulation.
___ 16.) True/False. Cold-air damming is a factor in causing more freezing rain in states
east of the Appalachian Mountains, such as the Carolinas and Virginia, relative to states
at the same latitude west of the mountains.
___ 17.) True/False. “Self development” of cyclones relates to the fact that temperature
advections at lower levels can serve to strengthen the upper-level wave, creating a
positive feedback.
18.) Match the surface observations below to their most likely locations on the sea-level
pressure analysis below.
___
___
___
___
___
___
A:
B:
C:
D:
E:
F:
19.) This semester, we spent quite a bit of time examining situations in which lifting a
layer of air changed the stability of the layer. The following series of true/false
questions summarizes this topic.
___ a.) Lifting a layer of air always results in a decrease in stability of the layer.
___ b.) When moisture decreases strongly with height in a layer, and the layer is lifted to
saturation, the lapse rate will increase.
___ c.) Layer lifting is associated with significant stability change only if more latent
heat is released in one part of the layer relative to other parts of the layer.
___ d.) A sounding that has zero CAPE can rapidly destabilize when lifted.
___ e.) Many severe weather soundings in the Great Plains exhibit potential instability
due to layer lifting.
___ f.) Even without a lifting mechanism, layers of air with dry air above moist can
destabilize due to this process.
___ g.) An initially stable layer with very moist air aloft and very dry air beneath will
become unstable if lifted far enough.
20.) The sounding below was taken at 00 UTC 21 August, 2007, at Greensboro, NC.
Use this to answer the following questions:
___ a.) Which layer exhibits a temperature lapse rate closest to the dry adiabatic value?
(i) 150-100 mb
(ii) 925-850 mb
(iii) 250-175 mb
(iv) 500-600 mb
___ b.) Of the layers listed in a.), which is the most stable?
c.) Would you expect convective storms based on this sounding? _____ (yes or no)
Justify your answer briefly below in terms of the ingredients needed for
convection. Consider a time frame of a few hours near the time of the sounding.
21.) Lightning true/false
___ a.) Lightning has not been observed outside of mixed-phase clouds.
___ b.) The electrification process of convective clouds involves collisions between
ice crystals and hail or graupel.
___ c.) The majority of lightning discharges are not of the cloud-to-ground variety.
___ d.) Positive lightning discharges originating in thunderstorm anvils often have
larger current than do negative lightning.
22.) Order the following steps in a lightning discharge chronologically by placing a
number from 1 to 5 in the blank space to the left of each of the following:
___ audible thunder
___ dart leader
___ step leader
___ return stroke
___ 1st bright lightning visible
___ 23.) Which of the following best explains why the moist adiabatic lapse rate is
smaller than the dry adiabatic rate?
a.) Moist air holds heat more strongly than dry air due to the presence of water.
b.) If saturated air rises, latent heat is released due to condensation, offsetting the cooling
due to expansion.
c.) If air is dry, it has a smaller heat capacity and therefore cools more quickly as it rises.
d.) The moist adiabatic lapse rate tends to happen in warmer conditions, meaning that
less cooling results and the lapse rate value is smaller.
24.) Numerical weather prediction models do not provide perfect forecasts, even with
short lead times of a few days. Which of the following are factors that contribute
significantly to model forecast errors? Check all that apply.
___ a.) Errors in model initial conditions due to poor data or a lack of data.
___ b.) Errors in the ways that models represent physical processes in the atmosphere.
___ c.) Inaccurate data for model parameters such as the solar and gravitational
constants.
___ d.) Insufficient knowledge of the governing equations for the atmosphere.
25.) Match the three hypothetical wind shear profiles shown below with the most likely
type of thunderstorm that would result, provided that the other ingredients needed for
convective storms were present.
(i) air mass thunderstorm
___ a.
___ b.
___ c.
(ii) squall line
(iii) supercell thunderstorm
___ 26.) Which of the following best defines the term dryline, and its relation to severe
weather?
a.) Dryline is another name for a cold front that has very dry air behind it; the lift
accompanying the front can cause convective storms and severe weather.
b.) The dryline is often found in the high plains separating continental tropical from
maritime tropical air; severe storms can form in the associated convergence zone.
c.) The dryline is a high plains feature that results from the outflow from strong
storms; this feature is found in the rear inflow jet of supercell thunderstorms.
d.) Drylines mark the location of severe weather, and they can move. During the
recent Alabama tornado outbreak, the dryline moved to the Atlantic coast.
___ 27.) Approximately what fraction of supercell storms produce tornadoes?
a.) more than 99%
b.) roughly 90%
c.) 40-50 %
d.) 10-20%
e.) Less than 1%
___ 28.) Recent studies and theory concerning tornado formation (tornadogenesis)
indicates the importance of the rear-flank downdraft (RFD) to this process. What
characteristics of the RFD seem to favor tornado formation?
a.) A strong and cold RFD is most likely to be associated with tornado formation.
b.) RFDs that had intermediate temperature and strength seemed to be best correlated
with tornado formation.
c.) Relatively warm RFDs (more buoyant air) are more favorable for tornadogenesis.
d.) Recent studies and field programs have disproven the idea that the RFD is important
to tornadogenesis.
___ 29.)Which of the following best describes the difference between the original Fujita
scale and the Enhanced Fujita scale?
a.) The original Fujita scale was based on measured wind speeds, but since observations
are sparse with tornadoes, the new scale uses damage and radar data to measure them.
b.) The enhanced Fujita scale was expanded to include an EF6 category after several very
strong tornadoes were measured with Doppler radar that exceeded the old F5
category.
c.) The original Fujita scale was based on damage to houses, whereas the Enhanced
version includes damage to additional, more commonly found structures.
d.) Actually, the scales are the same, the National Weather Service just decided to
rename the scale in 2009.
30.) True/False concerning differences between the tropical and mid-latitude atmosphere.
___ a.) In the tropics, hydrostatic balance is rarely observed.
___ b.) The midlatitude atmosphere is closer to a state of geostrophic balance than is the
tropical atmosphere.
___ c.) The tropopause is higher in the tropics.
___ d.) The midlatitudes are characterized by a westerly jet stream aloft; this feature is
not present in the tropics.
31.) Which of the following represent similarities between hurricanes and extratropical
cyclones? Check all that apply.
___ a.) Both hurricanes and extratropical cyclones exhibit convergence in the lower
troposphere.
___ b.) Hurricanes and extratropical cyclones both are accompanied by high pressure
aloft near the tropopause level.
___ c.) Hurricanes form in association with an upper-level (easterly) jet stream, and
cyclones also form in the vicinity of an upper-level (westerly) jet stream.
___ d.) Both hurricanes and cyclones are warm-core systems, meaning that their
circulations weaken with increasing height.
___ e.) Both hurricanes and extratropical cyclones are often accompanied by clouds and
precipitation.
___ f.) Both cyclones and hurricanes can be associated with strong frontal systems.
___ 32.) Which of the following best explains the “stadium effect” in hurricanes?
a.) The stadium effect is due to the strong surface low pressure; air rushing in to the
system at low levels has to rise, and when it does, it spirals outward.
b.) Rising air expands due to pressure decreasing with height. As air rises in the
eyewall, it expands, and so does the eyewall, which produces the stadium effect.
c.) This is due to the warm-core nature of hurricanes; weakening of the inward pressuregradient force with height leads to outward deflection of rising air in the eyewall.
d.) The stadium effect is due to the low latitude of hurricanes. The Coriolis force, being
weaker at low latitudes, leads to expansion of the storm with height.
____ 33.) Consider the plot below. The hurricane has a rotational wind speed of 80
knots, and the motion of the system is towards the north at 12 knots. Fill in the blank
values with the estimated wind speeds based on this information.
____ kts
north
____ kts
east
____ kts
____ kts
34.) Which elements contribute to the development and intensity of a hurricane storm
surge? Check all that apply.
___ a.) The low pressure of the hurricane results in an increase in sea level near the
storm.
___ b.) Wind driving water towards a coast or shoreline increases the surge.
___ c.) The action of wind waves, which enhances the inland extension of the surge.
___ d.) The size of the storm; larger storms yield larger storm surges.
35.) What is the approximate lowest surface pressure and strongest wind speed ever
observed in the strongest hurricane or typhoon on record?
a.) 800 mb and 400 mph winds
b.) 870 mb and 200 mph winds
c.) 925 mb and 150 mph winds
d.) 975 mb and 100 mph winds
___ 36.) Which best explains why hurricanes often move from east to west, opposite the
motion of typical mid-latitude storms?
a.) Because hurricanes are closer to the equator, where the Coriolis force is weaker.
b.) Because hurricanes are often located to the south of the subtropical high pressure
systems, meaning easterly prevailing flow.
c.) The upper-level jet stream in the tropics is easterly, so weather moves that way.
d.) Hurricanes have anticyclonic flow aloft (high pressure), so the move in the opposite
sense as mid-latitude low pressure systems.
___ 37.) Which of the following best explains why hurricanes are not observed to form
over land?
a.) Over land, the air is too dry to support thunderstorms and enough latent heat
release to spawn a hurricane.
b.) Over land, wind shear is typically larger, and so thunderstorms get sheared apart
rather than organizing into hurricanes.
c.) The feedback between wind speed and the extraction of heat and moisture from
the surface works strongly over water, but not over land.
d.) Over land, the surface is typically rougher, and the increased friction does not
allow a strong storm like a hurricane to spin up.
___ 38.) Which of the following best explains why hurricanes are not observed to form
right at the equator?
a.) This zone is where the ITCZ is located, and the ITCZ is characterized by cloudy
skies and stable air, both of which inhibit hurricane formation.
b.) At the equator, there is upwelling of water and locally cooler sea-surface
temperatures. The water is too cold for hurricanes to form.
c.) Wind shear is strong over the equator, so despite the presence of thunderstorms
there, they just get sheared apart and cannot organize into hurricanes.
d.) In an initial disturbance, Coriolis deflection is needed in order to prevent the weak
low pressure system from just “filling in”, and the Coriolis is zero at the equator.
___ 39.) Which of the following best defines the relation between weather and climate?
a.) Climate can be thought of as a measure of the average and extreme weather conditions
that prevail at a given location over time.
b.) Climate operates on different time scales than does weather, and so there is no direct
link between them.
c.) The tendency towards a larger or smaller number of a given type of weather event can
be related to shifts in climate.
d.) Both a.) and c.)
___ 40.) One useful data type for learning about past climates is obtained from ice cores,
usually obtained from Greenland or Antarctica. Which of the following best explains the
types of information that can be obtained from ice core data?
a.) Oxygen isotope analysis can tell us about past levels of global ice cover, an indirect
measure of the global temperature.
b.) Trapped air bubbles in the ice can be extracted and analyzed to determine past
atmospheric composition.
c.) The composition of the ice is a direct measure of past temperature, and tells us what
the temperature of the air was at the time the snow that made up the core fell.
d.) both a.) and b.)
e.) all of the above.
41.) For each climate-change mechanism listed below, indicate the time scale over which
it is believed to influence climate (based on past data).
___ continental drift
a.) changes over 10,000-100,000 years
___
___
___
___
aerosols from volcanic eruptions
variations in sunspot activity
Changes in atmospheric composition
changes in earth’s orbital parameters
b.) changes over many millions of years
c.) changes over decades to centuries
d.) changes over 10-20 billion years
e.) Changes over 1-5 years
___ 42.) By what approximate amount does the earth’s surface temperature change
between glacial and interglacial periods?
a.) 50 C
b.) 25 C
c.) 10 C
d.) 1C
e.) 0.1C
___ 43.) If the earth had no greenhouse gases in the atmosphere, the average surface
temperature would be about ______ C colder than at present.
a.) 10C
b.) 30C
c.) 1C
d.) 70C
e.) 100C
44.) Suppose that earth was in an ice age, with the current continental configuration.
Which combination of Milankovitch orbital parameters would most likely result in
warming (and end of the glaciation)? Circle the correct choices
(i) axial tilt: (large, intermediate, or small)
(ii) precession: (aphelion during northern winter, aphelion during northern summer)
(iii) eccentricity: (large, intermediate, or small)
45.) There is a consensus that the earth’s global surface temperature has warmed. Upon
what types of measurements is this consensus based? Check all that apply.
___ a.) The surface temperature record as measured by thermometers.
___ b.) Global averages of glacier mass balance
___ c.) Global measurements of sea-ice extent and volume
___ d.) Rises observed in global sea levels
___ e.) Satellite and ship measurements of sea-surface temperature
___ 46.) By how much, approximately, has the earth’s global surface temperature
warmed in the past 50 years?
a.) 10 C
b.) 5 C
c.) 0.5C
d.) 0.1 C
e.) none
___ 47.) Which of the following charactistics best explain why greenhouse gases are
stronger absorbers and emitters of IR radiation?
a.) These gases are all made up of different elements; gases made up of only one element
cannot absorb or emit infrared wavelengths.
b.) Greenhouse gases are composed of three or more atoms, allowing vibrational and
rotational interactions with low-energy infrared radiation.
c.) Greenhouse gases are easily split apart (dissociated) by infrared wavelengths because
of weaker chemical bonds; molecular oxygen and nitrogen have stronger bonds and
cannot be split by IR wavelengths.
d.) Greenhouse gases are more abundant in the atmosphere, and therefore absorb more
infrared energy than do gases such as oxygen and nitrogen.
48.) Based on the best available projections, which of the following are determined to be
highly likely results of anthropogenic climate change? Check all that apply.
___ Surface warming will be strongest in the equatorial regions, reaching 5-10C warming
by the year 2100.
___ Sea level will rise in the range of tens of centimeters to a meter by the year 2100.
___ Hurricanes will likely become much more numerous, with hurricane season being
longer and more intense.
___ Precipitation patterns will shift, with generally drier conditions in the subtropics but
with more precipitation at higher latitudes.
___ 49.) Which of the following best summarizes the physical processes that are
expected to be responsible for projected sea-level rise?
a.) Melting of sea ice and glacial ice
b.) Thermal expansion as the oceans warm along with melting sea and glacial ice
c.) Thermal expansion as the ocean warms along with melting glacial ice
d.) Thermal expansion as the ocean warms along with melting sea ice
___ 50.) Based on the IPCC assessment report, drawn from outcomes of many different
climate models and model scenarios, what is the expected range of global-average
surface temperature warming by the year 2100?
a.) 10-15C
b.) 5-10C
c.) 1.5-5C
d.) 0.5-1 C
e.) 0-1.5C
___ 51.) Climate models can be run from the past to see if they can accurately predict the
future. Which of the following best describes the outcome of these experiments?
a.) There is something wrong with the climate models, because they predict much more
warming than has been observed to date.
b.) Climate models are able to reproduce global temperature trends, but only when
aerosols, solar forcing, and greenhouse gas changes are taken into account.
c.) The models are unable to predict the warming that has been observed to date; they
generally show steady trends in temperature, and end up too cool in their predictions.
d.) Climate models are able to reproduce observed global temperature trends as long as
greenhouse gas changes are included; other types of forcing are unimportant.
___ 52.) The warmest year on record, in terms of global surface temperature, was 1998.
Why was this particular year so anomalously warm, and why hasn’t the record since been
broken if anthropogenic warming is ongoing?
a.) That year featured a major volcanic eruption, which lead to the unusual emission of
heat-trapping greenhouse gases.
b.) 1997-1998 was a major El Nino event, and it is also hypothesized that solar forcing
may explain the lack of recent warming.
c.) The North Atlantic Oscillation (NAO) made that year very warm, and the years since
were cold due to a different NAO pattern.
d.) Anthropogenic climate change is not thought to be operating, and future natural trends
will likely eclipse any changes due to anthropogenic effects.
___ 53.) Which of the following best explains the impact of humans on climate?
a.) The human influence is almost entirely due to greenhouse gas emissions, which in of
themselves exert a strong warming influence.
b.) Human influences extend beyond greenhouse gas emissions, and the influence of
land-use change may also be very important.
c.) Greenhouse gas increases are important, and the water vapor feedback amplifies the
warming effect from a given amount of anthropogenic greenhouse gas emission.
d.) both b.) and c.)
e.) all of the above.
___ 54.) Which of the following best summarizes the linkage between climate change
and hurricane intensity?
a.) Recent observed increases in strong hurricanes are almost certainly due to
anthropogenic climate change.
b.) Recent trends in hurricane activity do not appear to be anomalous when taken in
context of past observations and data limitations.
c.) Future climate change may lead to some increase in hurricane intensity, but this
increase is offset by warming aloft, which works against hurricane intensity.
d.) Warming sea surface temperatures is beginning to result in more hurricanes, and this
trend is expected to continue in the future.
___ 55.) Which of the following best describes the difference between primary and
secondary pollutants?
a.) Primary pollutants are break down in the presence of solar radiation (photodissociate),
and then release harmful substances into the atmosphere.
b.) Secondary pollutants produce harmful chemicals via chemical reactions between
primary pollutants and other gases.
c.) Secondary pollutants are not generally deemed as significant of a threat to society and
the environment, hence the name “secondary pollutants”.
d.) Primary pollutants occur naturally in the atmosphere, and are thus not technically
“pollutants”.
___ 56.) Which of the following best explains why the ozone layer is located between 10
and 50 km in altitude?
a.) Because ozone is light, it rises above much of the dense atmosphere below.
b.) This layer is in the stratosphere, which is safely above the layer where CFCs are
emitted. Below this altitude, CFCs have destroyed most of the ozone.
c.) At altitudes below this range, there is insufficient intense solar radiation to
photodissociate oxygen; atomic oxygen is needed to form ozone.
d.) At altitudes above this range, there isn’t sufficient density to get the 3-body ozoneforming reaction to operate efficiently.
e.) Both c.) and d.)
f.) all of the above.
____ 57.) True/False Tropospheric ozone is a primary pollutant.
___ 58.) Which of the following best describes the cause of the Antarctic ozone hole?
a.) CFC emissions are now banned in the Northern Hemisphere, but CFC production
continues in the Southern Hemisphere. This has led to strong ozone depletion
there.
b.) When temperatures get cold enough, polar stratospheric clouds form; reactions on
the cloud particles yield molecular chlorine, which then dissociates as the sun rises
in the Antarctic spring, releasing atomic chlorine and destroying ozone.
c.) The Antarctic features a high-latitude polar landmass, with extreme cold. The
extremely cold surface temperatures allow reactions to take place which destroy
ozone there.
d.) none of the above.
___ 59.) The concentration of Cl released by CFCs in the stratosphere is much less than
the concentration of O3; which best explains why the ozone layer is at risk?
a.) Because there is so little ozone to begin with, any depletion is a serious issue.
b.) Because chlorine reacts with ozone in a way that regenerates the chlorine atom,
allowing a single chlorine to cycle through many ozone molecules.
c.) Actually, the chlorine concentration can equal or exceed that of ozone in certain
locations.
d.) Chlorine is capable of reacting with many ozone molecules at the same time, making
it very efficient in ozone destruction.
___ 60.) Which of the following best describes the current status of the ozone hole?
a.) It continues to worsen each year, and will likely continue to do so in the near future.
b.) The ozone hole has stabilized, and seems to have reached somewhat steady intensity
in recent years.
c.) It has shown steady improvement for several years in a row, and is expected to stop
happening entirely within about 10 years.
d.) The ozone hole still happens each year with nearly equal size and intensity, but the
duration has been getting steadily shorter each year.
Have a great summer, and I hope to see you in a few years in MEA 443 if not before!