Weather and Climate Determine Biomes Chapter 6 Weather and Climate Determine Biomes

Core Case Study Climate Change: India Severe Droughts What are farmers doing to insure they can plant and harvest crops? Figure 5-1

Layers of the Atmosphere

Layers of the Atmosphere

CLIMATE: A BRIEF INTRODUCTION Weather is a local area’s short-term physical conditions such as temperature, precipitation and wind. Climate is a region’s average weather conditions over a long time. Data for temperature and precipitation averages are used to determine predicted biomes. Latitude and elevation help determine climate. (Latitude is attitude, Longitude is longer dude)

Weather examples Jet stream: http://www.youtube.com/watch?v=CgMWwx7Cll4&safety_mode=true&persist_safety_mode=1&safe=active Tornadoes: http://www.youtube.com/watch?v=cvOut9VUqKY&feature=fvwrel&safety_mode=true&persist_safety_mode=1&safe=active Hurricanes: http://www.youtube.com/watch?feature=fvwp&v=5iN352idLks&NR=1&safety_mode=true&persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=OEPZOC6YHUc&feature=related&safety_mode=true&persist_safety_mode=1&safe=active

Earth’s Current Climate Zones Figure 5-2

Climates and Biomes Biome Temperature Range Precipitation Polar Ice S high 50 C, W Avg -27 C 10 inches Subarctic 5 to 7 months sub zero 15 inches Cool Temperate NY, NY: 25 F to 81 F 28 to 62 inches, rain shadow Highland Mountains Varies Warm Temperate North Carolina 25 inches Dry Range above freezing < 20 inches Tropical 64 F all year 28 inches (2.4 in/month)

Solar Energy and Global Air Circulation: Distributing Heat Global air circulation is affected by the uneven heating of the earth’s surface by solar energy causing seasonal changes in temperature and precipitation. Figure 5-3

Students try: In groups of 5, imitate the photo with a globe and flashlight. Discussion Questions: What part of the earth receives the most sun? Why are seasons different in Australia compared to the US? What part of the earth receives the least sun? Why is it dark for large lengths of time in Alaska? What else did you notice?

(sun aims directly at equator) Winter (northern hemisphere tilts away from sun) Spring (sun aims directly at equator) 23.5 ° Solar radiation Summer (northern hemisphere tilts toward sun) Figure 5.3 Natural capital: as the planet makes its annual revolution around the sun on an axis tilted about 23.5°, various regions are tipped toward or away from the sun. The resulting variations in the amount of solar energy reaching the earth create the seasons in the northern and southern hemispheres. Fall (sun aims directly at equator) Fig. 5-3, p. 102

Heat released radiates to space Moist surface warmed by sun LOW PRESSURE HIGH PRESSURE Heat released radiates to space Condensation and precipitation Cool, dry air Falls, is compressed, warms Rises, expands, cools Warm, dry air Hot, wet air Figure 5.5 Natural capital: transfer of energy by convection in the troposphere. Convection occurs when hot and wet warm air rises, cools, and releases moisture as precipitation and heat (right side). Then the more dense cool and dry air sinks, gets warmer, and picks up moisture as it flows across the earth’s surface to begin the cycle again. Flows toward low pressure, picks up moisture and heat HIGH PRESSURE Moist surface warmed by sun LOW PRESSURE Fig. 5-5, p. 103

Demo: Humidity Dew point: Temperature at which water vapor condenses Relative Humidity: the amount of water vapor in a mixture of air and water vapor, when it reaches 100% we say the air is saturated. Clouds creation and beaker Demo Phet: gas-properties_en (1) http://phet.colorado.edu/en/simulation/gas-properties

Tropical deciduous forest Cold, dry air falls Cell 3 North Moist air rises — rain Polar cap Cell 2 North Arctic tundra Evergreen coniferous forest 60° Cool, dry air falls Temperate deciduous forest and grassland 30° Desert Cell 1 North Tropical deciduous forest Moist air rises, cools, and releases Moisture as rain 0° Equator Tropical rain forest Tropical deciduous forest 30° Desert Cell 1 South Figure 5.6 Natural capital: global air circulation and biomes. Heat and moisture are distributed over the earth’s surface by vertical currents, which form six giant convection cells at different latitudes. The resulting uneven distribution of heat and moisture over the planet’s surface leads to the forests, grasslands, and deserts that make up the earth’s biomes. Temperate deciduous forest and grassland Cool, dry air falls 60° Cell 2 South Polar cap Cold, dry air falls Moist air rises — rain Cell 3 South Fig. 5-6, p. 103

Cold deserts Westerlies Forests Northeast trades Hot deserts Forests Equator Figure 5.4 Natural capital: because of the Coriolis effect the earth’s rotation deflects the movement of the air over different parts of the earth, creating global patterns of prevailing winds that help distribute heat and moisture in the troposphere. Southeast trades Hot deserts Forests Westerlies Cold deserts Fig. 5-4, p. 102

Coriolis http://www.youtube.com/watch?v=aeY9tY9vKgs&safety_mode=true&persist_safety_mode=1&safe=active

Topography and Local Climate: Land Matters Interactions between land and oceans and disruptions of airflows by mountains and cities affect local climates. Figure 5-8

Dry habitats Moist habitats Prevailing winds pick up moisture from an ocean. On the windward side of a mountain range, air rises, cools, and releases moisture. On the leeward side of the mountain range, air descends, warms, and Releases little moisture. Dry habitats Moist habitats Figure 5.8 Natural capital: The rain shadow effect is a reduction of rainfall on the sides of mountains facing away from prevailing surface winds. Warm, moist air in prevailing onshore winds loses most of its moisture as rain and snow on the windward (wind-facing) slopes of a mountain range. This leads to semiarid and arid conditions on the leeward side of the mountain range and the land beyond. The Mojave Desert in the U.S. state of California and Asia’s Gobi Desert were both created by this effect. Fig. 5-8, p. 105

Sea Breezes: Day

Sea Breeze: Day Vs. Night

BIOMES: CLIMATE AND LIFE ON LAND Different climates lead to different communities of organisms, especially vegetation. Biomes – large terrestrial regions characterized by similar climate, soil, plants, and animals. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors.

BIOMES: CLIMATE AND LIFE ON LAND Figure 5-9

Tropic of Cancer Equator Tropic of Capricorn High mountains Polar ice Polar grassland (arctic tundra) Tropic of Capricorn Temperate grassland Figure 5.9 Natural capital: the earth’s major biomes—the main types of natural vegetation in various undisturbed land areas—result primarily from differences in climate. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Human ecological footprints (Figures 3 and 4 on pp. S12–S15 in Supplement 4) have removed or altered much of the natural vegetation in some areas for farming, livestock grazing, lumber and fuelwood, mining, and construction. Tropical grassland (savanna) Chaparral Coniferous forest Temperate deciduous forest Tropical forest Desert Fig. 5-9, p. 106

Recognizing Climates: In the biome map the southern tip of South America is brown, but the northern is green. Come up with a hypothesis why that happens.