1 Introduction to Geography Chapters 2 & 3: Weather and Climate, & Landforms
Objectives for chapters 1 & 2 are to be able to: Tell how solar radiation creates atmospheric patterns, Explain how precipitation forms, Describe global atmospheric circulation and the varying climates of the world, Define plate tectonics, Talk about differences in plate boundaries and boundary-related faults, Differentiate between types of volcanoes, 2 Explain how water, air, and other entities transform landscapes
3 Weather and Climate Weather: Day-to-day variations in temperature and precipitation Climate: Statistical summary of weather conditions through time
4 Objective: tell how solar radiation creates atmospheric patterns Radiant energy a by-product of Sun combining hydrogen atoms into helium Small portion intercepted by Earth Powers circulation of atmosphere and oceans Supports life on earth
Insolation 5 Like foot-candles, a measurement Amount of energy intercepted by Earth Factors Intensity of solar radiation determined by angle of incidence Variation in duration of sunlight by season 2011 Pearson Education, Inc.
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Atmosphere to Earth Heat Transfer Radiation (radiant energy): energy transmitted by electromagnetic waves (heat, light, radio, television) Wave length Shortwave (.2 to 5 microns): Insolation Most passes through atmosphere Longwave (5 to 30 microns): Energy reradiated from Earth Can be blocked by atmosphere 7
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9 Although anthropogenic sources may be contributing to the speed of end-of-ice-age global warming, consider: Plants like CO 2 Volcanoes let out volumes of CO 2 Bodies are made out of C CO 2 and carbonic-acid can add to fertility Over-acidified forests recover quickly The ocean has always been a CO 2 sink CO 2 forms a seed for cloud formation Increased snow increases reflectivity Fossil fuels are a limited resources Other technologies are already available
Variations in Angle of Incidence Daily and seasonal variation Seasonal angle dependent on latitude Tilt of Earth s axis = 23½ 10
11 Earth s Orbit Around the Sun
12 Storage of Heat Variable ability to store heat depends on material Water absorbs and releases more heat than land (acting like a season shock absorber ) Therefore Greater seasonal difference in temperatures in mid-continent areas in high latitudes (Asia, North America) Moderate climates near water
Objective: explain how precipitation forms Evaporation of water from surface of the oceans Water vapor rises in the atmosphere Converted to water (rain) or ice (snow) Powered by convection: movement of fluid when heated Advection = horizontal movements of air (wind) 13 2011 Pearson Education, Inc.
14 Condensation Conversion of water from vapor to liquid Capacity of air to hold water vapor: Depends on temperature Relative humidity: actual water content of air, expressed as percentage of what air could hold (temperature-adjusted percentage) Approaching 100% rain or snow soon Dewpoint Cooling air Causes increase in relative humidity Cooling beyond saturation condensation (clouds)
15 Convectional Precipitation Adiabatic cooling: cooling of air as it rises (1ºC per 100 meters; 5.5ºF. per 1000 feet) Saturation (100% humid.), cloud formation Condensation releases latent heat Clouds, rain or snow 2011 Pearson Education, Inc.
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Orographic Precipitation Air forced to rise over mountains Adiabatic cooling from expansion Descent on leeward side Decrease in relative humidity Leeward side of mountains much drier 17
Objective: describe global atmospheric circulation and the varying climates of the world 18
Frontal Precipitation Front: boundary between two large air masses In North America Continental polar air (cold) Maritime tropical air (warm) Dense, cold air below warm, less-dense air Cold air advancing = cold front Warm air advancing = warm front 19
20 Fronts
21 Fronts and Weather
Atmospheric Pressure Compare to energized tennis balls Layering temp. Insulation factor Measured with a barometer Differences Wind blows away from high pressure, toward low pressure 22 2011 Pearson Education, Inc.
Global Atmospheric Circulation Intertropical Convergence zone (ITCZ): warm air rising Subtropical highpressure zones: descent of cooled air that rose over ITCZ Mid-latitude low pressure zones: convergence of warm and cold air (mixing) Polar high-pressure zones: Cold 2011 Pearson Education, Inc. 23
Coriolis Effect Deflection of wind above rotating Earth Northern Hemisphere: to the right (clockwise) Cells rotating clockwise (down) and map-view counterclockwise up (on-back view clockwise) 24
25 Air Temperature Changes with elevation (6.4ºC per 1000 meters; 3.5ºF. per 1000 feet) Affected by: Topography Proximity to oceans Water availability 2011 Pearson Education, Inc.
26 Precipitation Averages
27 Classifying Climates Include temperature and precipitation Effects biological entities Köppen Climate Classification Wladimir Köppen, German geographer (1918) Used distribution of plants From plant ranges, identified temp. & precip.
28 Köppen Climate Classification 2011 Pearson Education, Inc.
29 Köppen Climate Classification 2011 Pearson Education, Inc.
30 End of Chapter 2
31 Introduction to Geography Chapter 3: Landforms
32 Geomorphology Study of landforms and processes that create them Lithosphere Rocks and soil Surface landforms Plains Mountains and hills Valleys
33 Landform Processes Endogenic: Internal forces beneath or at Earth s surface Mountain building Earthquakes Exogenic: External forces Chemical Erosion, water, wind
34 Objective: define plate tectonics Pangaea Hypothesis Thrown out as too Biblical, catastrophic Supercontinent Alfred Wegener (1900s) Plate Tectonics Theory: Accepted from 1960s
35 Past Plate Movements
36 Continental Shields
37 Earth s Crust Mantle: Rock beneath crust Tectonic plates: Pieces of Earth s rigid crust Plate movement Earthquakes Volcanoes Mountain building
38 Earth s Tectonic Plates
39 Locations of Earthquakes
40 Earthquakes Focus: Place of actual movement Epicenter: Surface directly above focus Seismograph Recording device for seismic waves Richter Scale (1935) Seismic waves: Recordable vibrations
41 Objective: be able to talk about differences in plate boundaries and boundary-related faults
Plate Boundaries Divergent: Plates spreading apart Seafloor spreading Rift Valleys in Africa Convergent: Plates pushing together Dense plates dive below Volcanic eruptions Transform: Plates grinding past each other (San Andreas Fault, California) 42
43 Faults Fractures in Earth s crust from stress Types Normal Divergent plate boundary Stretching Reverse Convergent plate boundary Compressed rock Appalachian Mountains, Wasatch Range, Himalayas Thrust: almost horizontal movement (same direction as a reverse fault)
44 Types of Faults Normal Fault Reverse Fault
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47 Rocks and Landforms Crust movement Landform creation Mineral composition of rocks
48 Types of Rocks, and the Rock Cycle Igneous Cooled molten crustal material Basalt, granite Sedimentary High pressure on layers accumulating on land or in water Sandstone, shale, limestone Metamorphic Sedimentary rocks compacted by heat, pressure Marble from limestone Slate from shale
49 Objective, to be able to differentiate between types of volcanoes
Volcanoes Magma: Molten rock Lava: Molten rock reaching Earth s surface Volcano: Surface vent for lava 50
51 Volcano Types Shield volcanoes Runny lava Basalt rock Mauna Loa, Hawaii Sedate Composite cone volcanoes Explosive Ash, pyroclasts, sulfurous gas
52 Volcano Types Shield Volcano
53 Composite Volcano
54 Minerals Natural substances that comprise rocks Types Sima (oceanic, shield volcanoes) Denser rocks Silicon, magnesium, iron minerals Sial (continental, composite volcanoes) Less dense Silicon and aluminum Distribution Near crustal movement Continental shields Hot spots
55 Objective: to be able to explain how water, air, and other entities transform landscapes
56 Weathering Process of breaking rock into pieces Chemical weathering: process of breaking down rock by, mainly by: Exposure to air and water Carbonic Acid Oxidation Mechanical weathering: process of breaking down rocks by physical forces Carbonic Acid: CO 2 + H 2 O H 2 CO 3
57 Mass Movement of Weathered Material Slow gradual movement near the surface, soil creep Dramatic movements such as rock slides, landslides, and mudflows
58 Sources Groundwater Overland flow Drainage basin: Area drained by a river and its tributaries Discharge: Volume of water carried per unit time Sediment transport: Movement of material Stream Drainage
59 Features of a Meandering Channel
60 Floodplain Nearly level surface at the valley bottom through which a river flows Shaped by meanders: Changes in direction Erosion from side where current is swifter Deposition on side where current is slower
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62 Stream Gradient Changes in gradient Steeper in upper reaches more erosion Gentler gradient in lower reaches more deposition Alluvial fans Deltas Concave profile
63 Ice, Wind, and Waves
Glaciers Rivers of ice flowing from colder to warmer locations Types Mountain Continental 64 Move sediment to form moraines Terminal moraines Lateral moraines Medial moraines
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68 Yukon, Canada
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70 Extent of Continental Glaciation in Last Ice Age
71 Shore Formations Beaches changed by repeated breaking of waves Capable of carrying enormous amounts of sediment
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73 Coastal Deposits
74 Sea Level Change
75 Human Impact on Coastal Erosion Final Slide
Objectives will be converted into exam questions Tell how solar radiation creates atmospheric patterns, Explain how precipitation forms, Describe global atmospheric circulation and the varying climates of the world, Define plate tectonics, Talk about differences in plate boundaries and boundary-related faults, Differentiate between types of volcanoes, 76 Explain how water, air, and other entities transform landscapes
77 End of Chapter 3