Chapter 8:Climatic Zones Chapter 11: Biomes

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Chapter 8Climatic Zones Chapter 11 Biomes
Part 2 Mild Climates
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Dry Climates (Group B)

• Fig. 8-14

• Distribution of B Climates
• Subtropical Dry Climates within 2035º of
  latitude
• Midlatitude Dry Climates within 35-55º of latitude

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• Distinctive Features of B climates
• Cover 30 of the total land area of the world
• More area than any other climate group
• Dry conditions prevail all year
• Potential evapotranspiration is greater than
  precipitation
• Two main sub-types based on precipitation
• BW is extremely arid (desert)
• BS is steppe (semi-arid)
• The two sub-types are further subdivided based on
  temperature
• h is for the hot subtropical desert (BWh, BSh)
• k is for the cold midlatitude desert (BWk, BSk)

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Dry Climates
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Deserts

• Subsidence from subtropical highs (STHs)

• Fig. 8-15

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The Desert Biome
Geographic distribution 30 of earths land
mass, mostly found at the interior of large
continents, i.e. in Africa (Sahara), USA
(Mojave), or Australia, Climate rain less than
250 mm (10 inches), evaporation gt
rain Vegetation typically succulent plants, i.e.
cacti, or thorn trees and shrubs. -adapted to
long dry spells. -if plants have leaves, then
they are wax-coated. -slow growth rates
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Subtropical Desert (BWh)

• Characteristics
• Precipitation extremely arid
• Scarce (most nearly rainless regions on Earth)
• Unreliable (extremely long periods without rain)
• Intense (brief, but heavy convective downpours)
• Very hot summers
• Enormous daily temperature range
• Coastal equatorward extensions advection fog
  off-shore

• Main locations
• Centered at latitudes 2530º
• Western sides of continents, including coasts
• Extend into continental interiors
• Northern Hemisphere
• Sonora-Colorado
• Sahara
• Arabian
• Southern Hemisphere
• Peru-Atacama
• Kalahari-Namib

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Subtropical Desert Climate

• Climographs

• Fig. 8-16

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Coastal Deserts
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Subtropical Steppe (BSh)

• Main locations
• Fringing BWh except on west coasts
• Characteristics
• Similar to BWh but more moderate
• Precipitation semiarid
• Dominant Controls
• Similar to BWh

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Subtropical Steppe

• Climographs

• Fig. 8-20

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Midlatitude Desert (BWk)

• Characteristics
• Precipitation meager
• Erratic, mostly showery
• Some winter snow
• Temperatures
• Hot summers, cold winters
• Very large annual temperature range
• Large daily temperature range
• Dominant Controls
• Rain shadow effects
• Distance from sources of moisture

• Main locations
• Central Asia
• Western interior of US
• Patagonia

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Midlatitude Desert

• Climographs

• Fig. 8-21

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Midlatitude Steppe (BSk)

• Main locations
• Fringing BWk
• Characteristics
• Similar to BWk (more moderate)
• Precipitation semiarid
• Dominant Controls
• Similar to BWk

Photo U.S. Great Plains, South Dakota
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Midlatitude Steppe
Midlatitude Grasslands

• Climographs

• Fig. 8-22

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Midlatitude (Temperate) Grassland Biome

• From 30 to 60 degrees latitude
• Temperate latitude
• Distinct Seasons
• Moderately or Seasonally Dry
• Grasses Dominate
• Fire Important (Drought and Grazing also)
• Prairie, Pampas and Steppe

• Fig. 11-40. An overgrazed range in Colorado

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Mild Midlatitude Climates (Group C)

• Fig. 8-23

• Mediterranean
• Humid Subtropical
• Marine West Coast

• Distribution of C Climates
• Equatorward margin of the middle latitudes
• Within 25-40º of latitude with some poleward
  extensions

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• Distinctive Features of C climates
• Temperatures
• Long summers, usually hot
• Short winters, relatively mild
• Precipitation
• No year-round moisture deficiency
• Some climates have seasonal shortages
• Three subtypes
• Mediterranean (Csa, Csb)
• Humid subtropical (Cfa)
• Marine west coast (Cfb, Cfc)

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Mild Midlatitude Climates
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Mediterranean Climates (Csa, Csb)

• Main locations
• Western side of continents
• 3040º of latitude
• Mediterranean coast
• California
• Central Chile
• Southern tip of Africa (Cape Town)
• Australia (Perth Adelaide)

• Fig. 8-26

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• Dominant Controls
• STH subsidence in summer (forces cyclonic storms
  poleward)
• Westerly winds and cyclonic storms shift
  equatorward in winter
• Precipitation

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Mediterranean

• Climographs

• Fig. 8-24

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Mediterranean Woodland and Shrub Biome

• Separated Trees with shrubs (thorny) and grasses
• Subtropical
• Hot and dry summers, Moderate Winters
• Chaparral has evergreen vegetation (Junipers)

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• Mediterranean Wildfires

• Fig. 11-33

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Humid Subtropical (Cfa, Cwa)

• Main locations
• Eastern sides of continents
• 2530º of latitude
• Southeastern United States
• Eastern China
• Southern Brazil and Uruguay
• Small areas in Africa and Australia

• Characteristics
• Temperatures
• Summers, warm to hot
• Winters, mild to cold
• Precipitation
• Abundant, mostly as rain
• Summer maximum

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Humid Subtropical

• Climographs

• Fig. 8-27

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Midlatitude Deciduous Forest Biome

• From 30 to 60 degrees latitude
• Temperate latitude
• Has distinct seasons
• Winter leaf fall
• Broadleaf trees with understory (of variable
  composition
• Also occurs in Riparian areas

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Midlatitude Forests

• Fig. 11-35

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Marine West Coast

• Main locations
• Western sides of continents, mainly
• 4065º
• Western and central Europe
• Largest area
• North America
• Oregon to Alaska
• New Zealand and eastern Australia

• Characteristics
• Temperature
• Very mild winters for latitude
• Precipitation
• Moderate to abundant, mostly in winter
• Many rainy days
• Much cloudiness
• Dominant Controls
• Westerly flow and oceanic influence year-round

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Marine West Coast

• Climographs

• Fig. 8-30

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Global Patterns Idealized

• General Models of the Climate Distribution

• Idealized seasonal precipitation patterns and
  climates along the west coasts of continents
  (Fig. 8-44).

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• Climatic Distribution in Africa A Practically
  Perfect Example

• Fig. 8-45 and Fig. 8-46