Introduction to Geography. Chapters 2 & 3: Weather and Climate, & Landforms

Transcription

1 1 Introduction to Geography Chapters 2 & 3: Weather and Climate, & Landforms

2 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 3 Weather and Climate Weather: Day-to-day variations in temperature and precipitation Climate: Statistical summary of weather conditions through time

4 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

5 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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7 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 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

10 Variations in Angle of Incidence Daily and seasonal variation Seasonal angle dependent on latitude Tilt of Earth s axis = 23½ 10

11 11 Earth s Orbit Around the Sun

12 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

13 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) Pearson Education, Inc.

14 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 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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17 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

18 Objective: describe global atmospheric circulation and the varying climates of the world 18

19 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 20 Fronts

21 21 Fronts and Weather

22 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 Pearson Education, Inc.

23 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

24 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 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 26 Precipitation Averages

27 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 28 Köppen Climate Classification 2011 Pearson Education, Inc.

29 29 Köppen Climate Classification 2011 Pearson Education, Inc.

30 30 End of Chapter 2

31 31 Introduction to Geography Chapter 3: Landforms

32 32 Geomorphology Study of landforms and processes that create them Lithosphere Rocks and soil Surface landforms Plains Mountains and hills Valleys

33 33 Landform Processes Endogenic: Internal forces beneath or at Earth s surface Mountain building Earthquakes Exogenic: External forces Chemical Erosion, water, wind

34 34 Objective: define plate tectonics Pangaea Hypothesis Thrown out as too Biblical, catastrophic Supercontinent Alfred Wegener (1900s) Plate Tectonics Theory: Accepted from 1960s

35 35 Past Plate Movements

36 36 Continental Shields

37 37 Earth s Crust Mantle: Rock beneath crust Tectonic plates: Pieces of Earth s rigid crust Plate movement Earthquakes Volcanoes Mountain building

38 38 Earth s Tectonic Plates

39 39 Locations of Earthquakes

40 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 41 Objective: be able to talk about differences in plate boundaries and boundary-related faults

42 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 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 44 Types of Faults Normal Fault Reverse Fault

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47 47 Rocks and Landforms Crust movement Landform creation Mineral composition of rocks

48 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 49 Objective, to be able to differentiate between types of volcanoes

50 Volcanoes Magma: Molten rock Lava: Molten rock reaching Earth s surface Volcano: Surface vent for lava 50

51 51 Volcano Types Shield volcanoes Runny lava Basalt rock Mauna Loa, Hawaii Sedate Composite cone volcanoes Explosive Ash, pyroclasts, sulfurous gas

52 52 Volcano Types Shield Volcano

53 53 Composite Volcano

54 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 55 Objective: to be able to explain how water, air, and other entities transform landscapes

56 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 57 Mass Movement of Weathered Material Slow gradual movement near the surface, soil creep Dramatic movements such as rock slides, landslides, and mudflows

58 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 59 Features of a Meandering Channel

60 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 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 63 Ice, Wind, and Waves

64 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 68 Yukon, Canada

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70 70 Extent of Continental Glaciation in Last Ice Age

71 71 Shore Formations Beaches changed by repeated breaking of waves Capable of carrying enormous amounts of sediment

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73 73 Coastal Deposits

74 74 Sea Level Change

75 75 Human Impact on Coastal Erosion Final Slide

76 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 77 End of Chapter 3