Transcript Class #20: Friday, October 20, 2010

Class #20: Friday,
October 20, 2010
The C and D Climate Types
Friday, October 15, 2010
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The C climate types: moist,
subtropical mid-latitude climates
• General characteristics: humid with mild winters
(average temperature between 27°F and 64°F);
distinct summer and winter seasons, ample
precipitation
• Extent: on the eastern and western regions of
most continents, from about 25° to 40° latitude
• Major types: humid subtropical (Cfa), marine
(Cfb), and dry-summer subtropical or
Mediterranean (Csa, Csb)
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Categorization of C climates
• C Moist with mild winters
– w dry winters
– s dry summers
– f wet all seasons (no dry season)
• a summers long and hot
• b summers long and cool
• c summers short and cool
• See table on page 480 for details
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Cfa: The humid subtropical climate
• Found principally along the east coasts of
continents 25° – 40° latitude; Southeastern
section of the US, eastern China, and southern
Japan. In SH, southeastern SA, Southeastern
coasts of Africa and Australia
• Hot muggy summers: under the influence of
the western side of subtropical highs, where
maritime tropical air flows poleward
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Cfa: The humid subtropical climate
• Upper-level ridges produce devastating heat
waves
• High temperatures, dew points make summer
weather more uncomfortable than the tropics
• Winter weather can be quite changeable
• Little snow
• Adequate and well-distributed precipitation
through the year
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Cfa: The humid subtropical climate
• Summer thunderstorms are common
• Tropical cyclones contribute to rainfall total in
the US and China
• Winter precipitation in mid-latitude cyclones
• Vegetation: in southeast US, thick pine forest
mixed with oak at higher latitudes
• Example: Mobile, Alabama
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Fig. 17-17, p. 488
Cfb: West coast marine, or marine
climate
• Along the west coast of most continents, from
latitude 40° to about 60°.
• Dominated by prevailing winds from the
ocean that moderate the climate (warmer
winters, cooler summers) compared to farther
inland. Summers are quite cool. If short, Cfc.
• Limited in horizontal extent by coastal
mountains
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Cfb: West coast marine, or marine
climate
• In western Europe, Cfb extends well inland
• For much of the year, low clouds, fog, drizzle
• Adequate precipitation in all months, from mP
air masses, is light or moderate
• Mountains enhance precipitation
• Along NW coast of NA, less rain in summer,
with northward migration of the subtropical
high
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Cfb: West coast marine, or marine
climate
• Characterized by a low annual temperature
range for such high latitudes
• Frequent precipitation and overcast skies act
to minimize daily variation in temperature
• Dense forest of Douglas fir where
precipitation is heavy
• Example: Port Hardy, Vancouver Island,
Canada
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Fig. 17-18, p. 488
Csa,b Dry-summer subtropical, or
Mediterranean climate
• On west coasts south of the Cfb climates
• On the shores of the Mediterranean Sea
• Summer dryness more pronounced than the
Cfb climates
• Mild (Csb) to hot (Csa) dry summers
• Dryness due to the sinking air in the
subtropical highs and their diversion of storms
poleward in summer
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Csa,b Dry-summer subtropical, or
Mediterranean climate
• During winter, subtropical highs move south,
and extratropical cyclones provide rain
• Typically, mild wet winters
• Csa: interior Mediterranean (Sacramento)
• Csb: coastal Mediterranean (San Francisco)
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Csa,b Dry-summer subtropical, or
Mediterranean climate
• Csa
– Summers are hot
– Winters a little colder than Csb
– Wider annual variation in temperature
• Csb
– Upwelling keeps air cool all summer
– Often shrouded in low cloud and fog
– Small annual range in temperature
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Fig. 17-19, p. 489
Csa,b Dry-summer subtropical, or
Mediterranean climate
• Snow is rare
• Land supports chaparral, a scrubby type of
low-growing woody plants and trees
• Mediterranean Sea: summers not so dry as
NA (far from subtropical high); also warmer
(no upwelling)
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Fig. 17-20, p. 490
Cw climate type
•
•
•
•
•
Winter dry season
Associated with the winter monsoon in Asia
Prevailing winds around continental High
Northern India and portions of China
In lower latitudes, higher altitudes keep them
from being tropical because they are too cool
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Fig. 17-21, p. 491
Table 1, p. 492
Fig. 3, p. 492
Fig. 4, p. 493
Fig. 17-22, p. 494
Fig. 17-23, p. 495
Fig. 17-24, p. 495