Quiz #3 Study Guide Pt. 2
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Cloud identification and
classification (45 pts). Ten cloud types. Clouds
are classified according to altitude and appearance; what key words
are used? You should be able to identify each of the 10 cloud types
from pictures (handrawn) or from a written description (eg. high
altitude cloud with a filamentary appearance). How would you
distinguish between Cc, Ac, and Sc or between Cs and As? What cloud
type could produce a halo? Common features on thunderstorm clouds:
anvil, mammatus, shelf cloud.
Sample Questions (from the Fall
2000 Quiz Packet) Quiz #3: 9,17
Quiz #4: 1,4,10,EC2 Final Exam: 8,44,50
***
Photocopied
Notes
(pps
99-100)
***
Satellite
Photographs
(10 pts). Infrared and
visible photographs. What do white and
grey on these two types of photographs represent? Thunderstorms
can produce severe weather; how would a thunderstorm appear on VIS and
IR photographs? How can satellites view clouds at night?
How is it possible to see air motions in regions where there aren't any
clouds? Geostationary and low-earth orbit satellites. Here
is a sample satellite photograph question.
Sample
Questions Quiz
#4: 16 Final Exam: 38
Formation
of
precipitation
(15 pts).
Approximate sizes of cloud condensation
nuclei, cloud droplets, and raindrops. It is relatively easy to form
cloud droplets (condensation); what about precipitation? Which of
the two processes below is the most important precipitation producing
process in the US?
Collision
coalescence process.
Produces rain in warm clouds (clouds in the tropics which contain water
droplets only). Falling droplets collide (why?) and stick together.
Effects of cloud thickness and updraft speed on raindrop size. Which
cloud type produces the largest raindrops and the heaviest
precipitation? About how large can raindrops get (why don't they get
any larger)?
Ice
crystal process.
Structure of a cold cloud. What are
supercooled water droplets? Where are they found in cold clouds?
Are there more water droplets or ice crystals in the mixed phase
region in a cold cloud? Are ice crystal nuclei abundant or scarce in
the atmosphere? Where does precipitation begin to form in a cold
cloud? Why are ice crystals able to grow while supercooled water
droplets do not? Riming (accretion). Graupel. Can the ice crystal
process produce rain or just frozen forms of precipitation?
Types of precipitation (20 pts).
Rain, virga, snow (snowflakes), drizzle,
fall streaks, sleet (ice pellets), hail, freezing rain, graupel
("soft hail" or snow pellets). What type of cloud and special cloud
characteristics are needed for hail formation (see Fig. 7-14 on p.
199)?