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October 08, 2013 Blue = tropical Red/orange = dry http://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification Purple/blue green = continental (moist, severe winters) Green = temperate (moist, mild winters) Grey = polar Wh see Wh dis clim October 08, 2013 Climate • A region's long-term weather patterns. > Weather = short term atmospheric conditions (temperature, precipitation, humidity, wind speed and direction, cloud cover, pressure). • 2 main factors characterizes different climates: average temperature and average precipitation • What causes different climates? October 08, 2013 Uneven heating of earth's surface by the sun (distance from equator) Cold Intermediate temperatures Hot Intermediate temperatures Cold http://www.zo.utexas.edu/faculty/sjasper/images/50.11.gif October 08, 2013 Seasons (tilt of earth's axis) October 08, 2013 Global air circulation: 1. Uneven heating of earth --> Convection 2. Rotation of earth on axis --> Coriolis effects -In Northern Hemisphere: Things get deflected to right. -In Southern Hemisphere: Things get deflected to left. http://serc.carleton.edu/earthlabs/climate/5.html Convection + Coriolis effects --> Global wind patterns that distribute heat and moisture (prevailing winds) October 08, 2013 Global air circulation: Convection Convection is the distribution of heat by the movement of masses of fluids (liquid or gas). October 08, 2013 Global air circulation: Convection Uneven heating of earth's surface results in three convection cells. Hadley cell-explains distribution of tropical rain forests and deserts • Air rises at the equator (most sun) – Air rising = low pressure *Air moves from low to high pressure October 08, 2013 Global air circulation: Convection Uneven heating of earth's surface results in three convection cells. Hadley cell-explains distribution of tropical rain forests and deserts *Air moves from low to high pressure • Air rises at the equator (most sun) – Air rising = low pressure • As air rises and cools, water condenses and precipitates (rains a lot over the equator) • Air gets "pushed" north and south from the equator • Cool air falls, is compressed, and warms. – Air falling = high pressure • Warm dry air over land = low precipitation, takes moisture from surface --> Deserts! October 08, 2013 Global air circulation: Coriolis effect http://serc.carleton.edu/earthlabs/climate/5.html http://nsidc.org/cryosphere/arctic-meteorology/factors_affecting_climate_weather.html October 08, 2013 Global Air Circulation Convection cells + coriolis effect = global wind patterns polar easterlies prevailing westerlies trade winds *Winds are named by their origin http://cas.umkc.edu/geosciences/env-sci/module4/weblab4.htm October 08, 2013 Ocean Currents Oceans absorb heat from the air (especially in tropic regions) Uneven heating differences in density warm and cold ocean currents **Redistribute heat from uneven heating of sun October 08, 2013 Ocean Currents Uneven heating differences in density warm and cold ocean currents *Redistributes heat from sun Currents driven by winds, earth's rotation, temperature difference (density gradient) + interrupted by continents -Clockwise in northern hemisphere -Counterclockwise in southern hemisphere October 08, 2013 Proximity to water *Heat is absorbed and released more slowly by water than by land* Bodies of water moderate climate. Sea breeze Land breeze http://www.nc-climate.ncsu.edu/edu/k12/.breezes October 08, 2013 Topography (mountains) Mountains interrupt the flow of prevailing surface winds. -Windward side: Air is forced up the mountain. Air expands, cools, and loses moisture as rain and snow. -Leeward side: Air flows down mountain. Air sinks, contracts, heats up, and the dry air mass draws moisture out of plants and soil below. *Rain shadow effect October 08, 2013 Elevation Parallel changes in vegetation type occur when we travel from the equator to the poles, or from lowlands to mountaintops. You can find extremely cold climates near the equator at high altitudes (Ex: Andes mountains) http://www.zo.utexas.edu/faculty/sjasper/images/f37.14.jpg October 08, 2013 Other factors: Monsoons--continents near warm oceans experience heavy rains called monsoons. Intense heating of land during summer creates low pressure air masses -> draws moisture from ocean -> leads to heavy rainfall. Human contribution: -Microclimates Concrete/asphalt absorb and hold more heat. Human impact (vehicles, appliance use) release lots of heat and pollutants. Results in higher temperatures, lower wind speeds (buildings block winds) -Greenhouse effect October 08, 2013 Biomes The distribution of organisms is determined largely by climate. Different climates support different communities of organisms. October 08, 2013 Biomes are large terrestrial regions characterized by similar climate, soil, plants, and animals. -Biomes are not uniform. Just a general characterization of an area. List of biomes: 1. Desert (Tropical, temperate, cold) 2. Grasslands > Tropical grasslands (savannas) > Temperate grasslands > Polar grasslands (tundra) > Chapparral 3. Forests > Tropical rain forest > Temperate deciduous forests > Evergreen coniferous forests > Temperate rain forest 4. Mountain biomes 5. Polar Ice October 08, 2013 Desert • Evaporation > Precipitation • 30% land surface • Hot day, cold night • Tropical desert--hot, dry. Few plants. Rocks and sand • Temperate desert--high temperature in summer, low in winter. More precipitation. Drought resistant shrubs and cacti/succulunts. • Cold desert--cold winters, low precipitation, sparse vegetaion http://environment.nationalgeographic.com/environment/habitats/desert-map/ October 08, 2013 Desert • *Organisms: beat the heat, every drop of water counts > Plants (stomata, water storage, leaves, root systems, life cycle) > Animals > Insects > Reptiles (waste) http://wc.pima.edu/~bfiero/tucsonecology/adaptations/adaptations_home.htm http://www.desertusa.com/survive.html http://wc.pima.edu/~bfiero/tucsonecology/adaptations/adaptations_home.htm • Desert ecosystems are very fragile. Why? Slow plant growth (water is a limiting factor) Low species diversity (difficult to survive in desert) Low nutrient cycling (low bacterial activity) October 08, 2013 Grasslands and Chaparral Distribution: -interiors of continents -too moist for deserts, too dry for forests http://environment.nationalgeographic.com/environment/habitats/grassland-map/ Characteristics: -Seasonal drought -Grazing by large herbivores -Occasional fires -Low average precipitation -Range in average temperatures October 08, 2013 Grasslands and Chaparral Grasslands • Tropical (savannas) • Temperate • Polar (tundra) October 08, 2013 Grasslands: -Tropical Grasslands/Savannas: • Warm temp year-round • alternating dry/wet seasons • Drought + grazing + fire inhibit growth of trees/bushes • Animals: farsighted, fast, stealthy. > Grazing and browsing hoofed animals > migration > specialized eating • Plants: survive drought • Human impact: rangeland, overgrazing, trees for firewood --> desert http://www.mnh.si.edu/mammals/pages/where/africa/waterhole.htm October 08, 2013 Grasslands: -Temperate grasslands • Cold winter, hot dry summer • Drought + fire + grazing + winds • Fertile soil due to decomposition of grasses + root systems • Tall v. short grass • Human impact: raise crops, raise cattle, build towns/cities October 08, 2013 Grasslands: -Polar grasslands/Arctic tundra ("marshy plain") • Low precipitation, mostly snow • Grasses, mosses, lichen, dwarf shrubs --> spongy mat • Growth in "summer" 6-8 weeks • Permafrost > waterlogged soil > forms seasonal wetlands, lakes, marshes, bogs, ponds • Organisms: insects, migratory birds, *need to survive cold • Human impact: oil drilling, mines, military bases http://www.ucmp.berkeley.edu/exhibits/biomes/tundra.php October 08, 2013 Why does the tundra have a fragile biome? Short growing season + cold! (soil and vegetation recover slowly) October 08, 2013 Chaparral Distribution: Borders deserts, coastal Climate: longer, rainy winters, foggy Vegetation: low-growing evergreen shrubs, small trees, leaves that reduce evaporation Fires! -> seeds sprout. October 08, 2013 Forest Biomes • Lots of precpitation to support trees • Forest = trees + other vegetation • 3 types > Tropical > Temperate > Boreal (polar) October 08, 2013 Forest Biomes -Tropical rain forest • Extremely diverse ecosystem • Plants: broadleaf evergreen, huge trees (buttresses), dense canopy*, vines *NPP http://www.blueplanetbiomes.org/rainforest.htm http://www.ecolibrary.org/page/DP9018 October 08, 2013 Forest Biomes -Tropical rain forest • Stratification of specialized plants and animal niches • Adaptation for pollination • Acidic, low nutrient soil--nutrients stored in biomass (quick recycling), not soil. • Human impact: logging, crops, grazing, minerals • Tropical dry forest http://rainforest-australia.com/Pollination_and_flowers.htm October 08, 2013 Forest Biomes -Temperate deciduous forests • moderate average temperature, change with seasons • long warm summer, cold winters, abundant precipitation • vegetation: broadleaf deciduous trees, more plant life at ground level, leaf litter • animals: predators, deer, small mammals • Human impact: fragmentation or loss of habitats, industrialization and urbanization *most disturbed October 08, 2013 Forest Biomes -Evergreen coniferous forests (boreals, taigas) • Subarctic--long dry, cold winters, short cool summers *variation in sunlight • Vegetation: coniferous evergreen trees (needle-shaped, waxy leaves, low diversity, grow fast in summer • acidic, low nutrient soil • Animals: bears, wolves, moose, lynx, many burrowing rodent species • Muskegs (acidic bogs) October 08, 2013 Temperate rain forest (coastal coniferous forest) • rain and moisture from ocean fog • moderate temperatures • Evergreens, ferns, mosses October 08, 2013 Mountain Biomes Dramatic changes in altitude, climate, soil, and vegetation • Erosion (slopes) when vegetation removed by natural disturbance or human • Islands of biodiversity • Forests, endemic species, sanctuaries for animals (people tend to not build on mountains) • Regulate climate--glacial ice (freshwater), ice/snow reflect solar radiation, gradually release melting ice, snow, and water October 08, 2013 Human Impact 1. Humans use, waste, or destroy 10-55% of NPP October 08, 2013 October 08, 2013