GEO 101, April 11, 2013
“D”
A
D and H climates and biomes
C
General review
D
E
Characteristics of both “D” and “E” climates
“D”
Great difference in seasons
60°
High latitudes - as latitude increases, overall
temperature decreases
Insolation extremes between summer and winter
30°
0°
30°
60°
No “D” in S. Hemis.
Worldwide Distribution of Climate “D”
Microthermal (severe mid-latitude) climates:
winter dominated but warm enough for trees
Dfa: Humid continental
moist all year
severe ranges of temperature
continentality
air mass difference
cP + cA all winter
mT briefly in summer
ground frozen and snow covered 1-5 months
Note difference in eastern and western side of continent
1
cP + cA air masses, mT briefly in summer, continentality
Dfc: Subarctic
Rivals E in winter low temperature
Taiga = snow forest: continuous belt across
North America and Eurasia
Treeline
Boreal forest
Animals of the “D” climates
Boreal Forest
Conifers
Needleleaf
evergreens
Pine, spruce,
fir, larch
Drier part is
tallgrass
prairie
2
Distribution of North American Peatlands
Bogs, mires, moors, muskegs
Drainage poor due to permafrost
Peat Bog
Biome: Biological community associated with
major climate region.
Comparison of carbon storage in forests
global warming scenarios
E
D
C
B
A
Decreasing precipitation 
H = Highland Climates
Mt. Kilimanjaro, Tanzania, 19,340 feet, 3°S
D
Df
Decreasing precipitation 
Major source of world’s lumber
3
Highland climates have high diurnal temperature range
Intensity of insolation related to
angle of sun’s rays
atmospheric transparency
altitude
HIGHLAND CLIMATES
Can be found at any latitude
Four Controls on Highland Climates
1. Altitude
Up in elevation = colder (normal lapse rate)
-6°C / 1000 m (-3.3°F / 1000 ft)
2. Latitude
Determines baseline conditions
temperature
seasonality
20,000 ft. mountain ≈ 65°F colder at top
Mt. Chimborazo, Ecuador, 20,000 ft
“A” average = 85°F at base
“H” = 20°F at top
10,000 ft. elevation change = 33°F temperature depression
Af
Tropical highland agricultural areas
Dfa
4
Molokai, Hawaii
3. Orographic Effect
Affects precipitation
windward, more
leeward, less
Casa Grande Peak, Big Bend National Park, Texas
4. Local Topography
Slope aspect
Exposed vs. protected
Highland vegetation is called
alpine vegetation
Basic biomes:
Broadleaf evergreen forest near the equator (Af, Am)
Altitude
Alpine tundra
Broadleaf deciduous forest in the mid-latitudes (Cfa)
Needleleaf evergreen
Broadleaf
Deciduous
Needleleaf evergreen forest in the north (Df, Cfb)
Broadleaf
evergreen
Grasslands in the semi-arid regions (BS, Aw, drier C &
D, ET)
Odd-ball plants in the deserts (BW)
Latitude
5
Alpine
Biomes are plant formations that are the result of
adaptations by plants to environmental parameters
associated with major climatic regimes. Biomes are
ecological regions, not evolutionary or taxonomic
regions.
Denver
Kansas
City
Cincinati
D.C.
Changes between biomes are not the same as
succession.
Cfb
Reno
San Cs
Francisco
Succession: replacement of one vegetation type by
another over time in the same place
Major loss of plants and animals worldwide is human
population growth = habitat destruction
DVD on World Population
A graphic simulation of the history of human population
growth published by Population Connection
http://www.youtube.com/watch?v=9_9SutNmfFk&feature
=related
Time 
Know the name and two characteristics of each of
the following climate types:
Af
Am
Aw
Tropical rainforest
Tropical monsoon
Tropical wet & dry
Never freezes
Rain all year
Broadleafed evergreens
Never freezes
Seasonal rain
No real dry season
Mostly broadleaf evergreen
Some deciduous trees
Never freezes
Dry in “winter”
Grasslands
BW Desert
BS
Steppe
P < ½ PET
Rain low & unreliable
Drought evaders & resistors
PET > P > ½ PET
Semi-arid
Short grass
Cfa Subtropical
Summer dominated, can freeze
Rain all year
Broadleafed deciduous
Cfb Marine West Coast Summer dominated, can freeze
Rain all year
Big needleleaf evergreens
Csa Mediterranean
Summer dominated, can freeze
Dry summer
Grassland
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Dfa
Dfc
Humid continental
Subarctic
Winter dominated
Rain all year
Needleleaf evergreen
ET
Tundra
EF
Frost
Too cold for trees
Short time above freezing
Grassland
Too cold for anything
Never thaws
No vegetation
H
Highland
Controlled by altitude,
latitude, slope aspect,
orographic effect
Alpine vegetation
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