Post on 23-Dec-2015
transcript
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– 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– 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– alternating 3 month wet and dry periods
dominated by movement of ITCZ
Monsoon – 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
– BW (Desert):– BS (Steppe):
Steppes
Dry short grass regions surrounding deserts There are cold and hot steppes Hot steppes are subtropical
– South Texas Cold steppes are at mid latitudes
– 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
– Sahara
Cold desert– Gobi
C climates
Essentially, it freezes but snow is not permanently on the ground in winter.– 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
– 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
– 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– 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.– Wet-and-dry: dry winter– Humid: no dry season
Humid Continental
Cold winters and warm summers Precip in every month
– Northern U.S.
Humid Continental (cool summers)– 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
– Most of Canada, Russia
E climates
Warmest month below 10°C. Essentially, where it’s too cold for trees to
grow– 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