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Global Climate Classification and Vegetation Relationships. Weather vs. Climate. Weather short-term condition of the atmosphere days, weeks meteorologists Climate long-term (30 year) average of weather conditions and extremes climatologists. Climate Determinants.
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Weather vs. Climate • Weather • short-term condition of the atmosphere • days, weeks • meteorologists • Climate • long-term (30 year) average of weather conditions and extremes • climatologists
Climate Determinants • Insolation and Temperature • latitude, altitude, land-water, ocean currents, mountain barriers • Precipitation • Air pressure (ITCZ and Subtropical Highs) • Air mass influences • Prevailing winds
The Köppen Climate Classification • A Tropical (equatorial regions) • B Deserts (arid, semiarid) • C Mesothermal (mild winter) • D Microthermal (boreal, cold winter)) • E Polar (always cold) • H Highland (mountains, plateaus)
The Köppen Climate Classification 3 letter system First letter = temperature Second letter = precipitation Third letter = finer shades of temp Csb = mediterranean C = middle latitude temps s = summer dry b = warm summers (as opposed to hot [a])
Tropical Humid Climates (Af) • 1/3 of Earth’s total surface (about 20 ºN to 20 ºS) • Consistently warm (all months > 18ºC/64.4 ºF) • Annual precipitation exceeds evaporation • Daily temp range exceeds annual temp range • Subcategories based on rainfall (ITCZ influence) • Tropical rainforest • Tropical monsoon • Tropical savanna
Tropical Rainforest (Af) • High rainfall all year (>2” / month) • Straddles Equator by 5o - 10o
Tropical Rainforest • Vegetation : Highest biomass on earth! Highest biodiversity on earth!Thousands of species, tall trees, many canopy layers, evergreen, broadleaf trees, epiphytes, lianas (vines), climbers, stranglers, ferns • Fauna:More species than all other biomes combined!, colorful insects, amphibians, reptiles, and birds, few large animals, high density of biomass and incredible species diversity • Other: Among most threatened biomes
Lianas Epiphytes Buttresses
Deforestation, Malaysia Strangler Fig 3-Toed Sloth, Panama
Savanna (Aw) – Tropical Grassland Climates • Region/Distribution: Subequatorial Africa, and South America, Southern India (25° N and S Latitude) • Vegetation: Continuous cover of grasses, scattered trees or shrubs • Fauna: Large grazing animals; antelope, zebra, giraffe, elephant, Predators: lions, leopards, cheetahs, hyenas • Other: Susceptible to desertification Masai Reserve, Kenya Acacia and Wildebeest Serengeti Plain, Tanzania
Dry / Semiarid Climates (B) • Occupy about 1/3 of Earth’s land area (Most extensive climate over land surface) • Evaporation exceeds precipitation (water deficit) • Subcategories • Desert (BW) • Steppe (BS)
Temperature: • Widest range: up to 100oF/day! • Hot at low latitudes, wide variation at higher latitudes Deserts (BW): • Precipitation: • Scarce: <10 inches/year • Unreliable: wide variation from average • Intense: convective downpours • Desert Causation: • High Pressure Cells and resultant stability • Rainshadows
Deserts • Vegetation: Widely scattered thorny bushes, cacti, small flowers, extensive shallow roots or long tap roots, shrubs, succulents • Fauna: Many rodents, lizards, toads, snakes and other reptiles, many birds, owls, vultures, many insects (adaptive strategies) • Other: Deserts cover roughly 1/3 of earth. May be growing due to desertification. • Steppe: semi-arid high elevation or high latitude
Desert Plant Survival Strategies • schlerophyllousadaptations - small, waxy leaves or thorns replace leaves • succulents - stems modified to spongy water storage structures • ephemerals(obligate seeders) - fast reproductive cycle • wide spacing with shallow roots - collect sparse rainfall Animal survival strategies?
Steppe (BS): temperate grasslands • more precipitation than BW • narrower temperature ranges • grasslands
Grassland (temperate) • Region/Distribution: Central North America, parts of Africa, Australia, SE South America (Pampas) • Soil: very fertile soils, best on earth • Vegetation: Grass tall to short prairie, pampas, steppe. Sod forming grasses, Sparse bushes, occasional trees in some areas • Fauna: large grazing animals, bison, antelope, wild horses, kangaroos, giraffes, burrowing animals: rabbits, prairies dogs…; predators: coyotes, lions, leopards…... • Other: Most N. American grasslands have been converted to agricultural fields. Wild grazers replaced by cattle, sheep, goats. Less than 1% of original grasses left.
Subtropical Forest Sarasota, Florida Mesothermal Climates (C) • “Middle temperature” • True seasonality (air mass conflict) • Subdivisions based on precipitation variation • humid subtropical • marine west coast • Mediterranean Marine West CoastTemperate RainforestOlympic Peninsula, Washington
Mesothermal Climates (C) Humid SubtropicalMarine West CoastMediterranean
Humid SubtropicalMidlatitude Forests • Hot summer, substantial year-round precipitation • Low latitude east coasts (warm currents). • Summer max precipitation. • Cold spells Cfa - New Orleans, LA
Temperate Forest (Deciduous) • Region/Distribution: Western Europe, East Asia, Eastern U.S.. Between 30-50° north or south • Soil: brown soils, good for agriculture • Vegetation: Broad-leafed deciduous trees, (120-150’ tall), oaks, hickories, maples,… • Fauna: mammals such as white tail deer, porcupines, raccoons, rabbits, squirrels, most carnivores eliminated by hunting i.e. wolf, mountain lion, bobcat; many birds; frogs and salamanders, snakes • Other: Biota well adapted to seasonality including hibernation, migration
Mediterranean • Dry summers (shifting subtropical highs) • Surrounds Mediterranean • Also on west coasts near 30o N and S (Australia, S. Africa, Chile)
Mediterranean • Region/Distribution: West coast and Central California, SW. Australia, tip of S. Africa, West Peru. Chile, Mediterranean (good wine places!) • Vegetation: Grassland, scattered trees (oaks, eucalyptus), scrub. Fire tolerant, sclerophyllous (hard leaf) evergreens, chaparral (scrubby evergreen) • Fauna: Burrowers like ground squirrels, gophers; deer, mountain lions, coyotes, many birds • Other: Susceptible to fire during dry season, some species need fire to regenerate, Susceptible to erosion and desertification, development, threatened biome
Microthermal Climates (D) Virtually restricted to Northern Hemisphere.
Subarctic Climates (Boreal or Taiga) • 50o-70o N latitude • long, bitterly cold winters • highest annual temp range: up to 100O F • Great annual temperature ranges (continentality, air mass conflicts) Dw – Calgary, Canada
Coniferous (Boreal) Forest – Koppen D • Region/Distribution: Northern parts of North America, Europe and Asia, South So. America, much of Russia • Vegetation: Coniferous (mostly evergreen) forest, ex. Spruce, Fir, Pine, Larch, needle-leaved • Fauna: Large herbivores: moose, elk; small herbivores: squirrels snowshoe hare, beaver; Predators: wolves, foxes, bears, lynx, weasel family; Mosquitoes in summer • Other: Acid rain, logging , oil drilling, hunting of predators
Fir Trees, Alaska Spruce Needles British Columbia