Climate Controls
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Transcript Climate Controls
Climatic Controls
Latitude
Altitude
Continentality
Prevailing Wind
Air Mass Variability
Topography
Ocean Currents
Land Use / Land Cover Change
Empiric classification:
Köppen and later modified by
Thornthwaite and Trewartha
looked at the global distribution of different
plant and animal species and attempted to
see how weather variables correlated with
these patterns.
Temperature and precipitation
Köppen climate classification
Five primary categories
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A Tropical
B Dry
C Mesothermal- “moderate”
D Microthermal- “low”
E Polar
BASIC WORLD CLIMATES
A climates
Mean temperature of coldest month is above
18°C (64°F)
Essentially, no freezes
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Tropical Rainy: no dry season
Tropical Wet-and-Dry: short dry season
Tropical Monsoon: long dry season
TROPICAL RAINFOREST
Annual precip > 80”
No real seasons
Sticky, humid air, with little wind
High sun angle all year
Tropical Savanna and Monsoon
Savanna
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Monsoon
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alternating 3 month wet and dry periods
dominated by movement of ITCZ
5 - 7 month wet and dry regime
Both have 40 – 80” precip/year and average
temps above 64°F every month
B climates
Arid and Semi-arid
P < PE
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BW (Desert):
BS (Steppe):
Steppes
Dry short grass regions surrounding deserts
There are cold and hot steppes
Hot steppes are subtropical
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Cold steppes are at mid latitudes
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South Texas
Montana
Both have approximately 10 – 20” annual
precip
Deserts
Hot and Cold deserts just like Steppes
Both have < 10” precip/year
Abundant sunshine
Hot desert
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Sahara
Cold desert
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Gobi
C climates
Essentially, it freezes but snow is not
permanently on the ground in winter.
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Mediterranean: dry summer
Wet-and-dry: dry winter
Humid: no dry season
Humid Subtropical
Mild winters with temperatures frequently
dipping below freezing (northern limits) to
infrequent freezes (southern limits)
Hot summers
Abundant precip throughout the year
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SE U.S.
Mediterranean
(dry summer subtropical)
No summer rain
Very little late spring/early fall rain
Cool moist winters and warm summers
Climate moderated by cold water
Abundant sunshine
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Southern Cal
Marine West Coast
Cool/cold and moist winters
Pleasant summers with temps generally not
exceeding 85°F
Summer is drier
Persistent fog, drizzle, gray skies for the
majority of the year
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Seattle, London
D climates
Coldest month is less than -3°C; warmest
month above 10°C.
Essentially, where snow remains on the
ground for part of the winter.
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Wet-and-dry: dry winter
Humid: no dry season
Humid Continental
Cold winters and warm summers
Precip in every month
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Northern U.S.
Humid Continental (cool summers)
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Located farther north with colder winters
Southern canada
Subarctic Boreal or Taiga
Brutal winters
Coniferous forests
Short cool summer with average temps
breaking 50F and frequently reaching the
70s
Not much precip 10 – 20”
Northern Hemisphere only
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Most of Canada, Russia
E climates
Warmest month below 10°C.
Essentially, where it’s too cold for trees to
grow
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Tundra: it thaws in summer
Ice Cap: it doesn’t
Tundra and Icecap
Tundra is treeless
Average temps do not break 50°F
Small flowering plants, lichens, mosses,
Horrible insects in summer when permafrost thaws
Icecap is frozen year round
Occasionally temperatures will rise above freezing
Alpine or Highland
Complex climates because of altitude
Can be a little of everything depending on
the elevation
WORLD CLIMATES
ANNUAL PRECIP