The Climate of the Earth

1. The Climate of the Earth Chapter 3

2. Earth-Sun Relationship Chapter 3 – Section 1

3. Weather Weather – the condition of the atmosphere in one place during a limited period of time Ex: looking out the window to see if you need an umbrella means you’re checking the weather

4. Climate Climate – term for the weather patterns that an area typically experiences over a long period of time Ex: not having to look out of the window because it is usually raining, so you take an umbrella anyway

5. Earth’s Tilt & Rotation The tilt is one reason for variations in sunlight Axis – an imaginary line running from the North Pole to the South Pole The angle of tilt never changes and because of it: not all places on the planet receive the same amount of direct sunlight at the same time

6. Temperature • Temperature is greatly affected by the earth’s tilt • The measure how hot or cold a place is • Warmer temperatures: areas that receive a lot of direct sunlight • Colder temperatures: areas that receive a less direct sunlight

7. Rotation Receiving light also depends on the side of planet that is facing the sun One full rotation takes up to 24 hours This also causes the alteration between day and night

8. Revolution While rotating on its axis, the earth is also traveling in an orbit around the sun A revolution is a trip around the sun It takes the earth a few hours more than 365 days to complete one revolution

9. Revolution & Tilt • Both the revolution & the tilt cause changes in the angle and amount of sunlight that reach different parts of the earth • These changes are called seasons • We experience different amounts of day and night, as well as different temperatures during seasonal changes

10. Revolution & Tilt Seasons are reversed north and south of the Equator Spring in the N. Hemisphere ~> fall in the S. Hemisphere Winter in the S. Hemisphere ~> summer in the N. Hemisphere

11. Tropic of Cancer This is the northernmost point on the earth to receive the direct rays of the sun Eventually the sun strikes directly on the line of latitude: 23 ½ ºNorth

12. Tropic of Cancer The rays reach the Tropic of Cancer on or about June 21 It gives the N. Hemisphere its longest day of sunlight This is also known as the summersolstice It marks the beginning of summer in the N. Hemisphere

13. Tropic of Capricorn Now the sun’s rays strike south of the equator reaching 23 ½ ºSouth This is the southernmost point where the sun’s direct rays reach

14. Tropic of Capricorn The rays reach the Tropic of Capricorn on or about December 21st It gives the N. Hemisphere its shortest day of sunlight It is also known as the winter solstice It marks the beginning of winter in the N. Hemisphere

15. The Poles • 6 months of the year, 1 pole is tilted toward the sun and receives continuous sunlight • The other pole is tilted away from the sun and receives little to no sunlight • Between March 20 – September 23: the sun never sets at the North Pole • It is known as the midnight sun

16. Land of the Midnight Sun

17. Greenhouse Effect • On the sunniest days in the warmest climates still only a part of the sun’s radiation passes through the atmosphere • Some is reflected back into space • Enough reaches the earth to warm the air, land, and water

18. Greenhouse Effect Earth acts like a greenhouse because it traps some heat and keeps it from escaping back into space too quickly It traps the warmth for growing plants even in cold weather This is known as the greenhouse effect

19. Greenhouse Effect • If too much heat escapes, the plants will freeze • If too much heat is trapped, the plants will dry out

20. General Rules of G.E. • The atmosphere provides just the right amount of insulation to promote life • 50% of the sun’s radiation that reaches the earth is converted into infrared radiation (heat) • Cloud and greenhouse gases absorb the heat reflected by the earth and radiate it back so that a balance is created

21. Today’s Situation • CO2 within the atmosphere has risen rapidly because of human interaction with the environment: • Burning of coal • Burning of petroleum • Burning of other fossil fuels • Burning of the tropical rain forests

22. Global Warming • Because of rising CO2 levels this has also increased a rise in global temperatures • This is called global warming • Some believe that if temperatures continue to rise, ice caps and mountain glaciers will melt and cause a rise in sea levels • Erosion of cliffs, beaches, and dunes could also increase • Places could become submerged

23. Global Warming

24. Factors Affecting Climate Chapter 3 – Section 2

25. Low Latitudes • Low Latitudes are located between the Tropic of Cancer and the Tropic of Capricorn • It includes the Equator and places here have warm to hot climates

26. High Latitudes • High Latitudes are located in the earth’s polar areas • Between March 20 – September 23 the polar area north of the Arctic Circle experiences continuous daylight/twilight • The polar area south of the Antarctic Circle experiences continuous daylight/twilight for the other 6 months of the year

27. Mid-Latitudes • The mid-latitudes are located: • North – between the Tropic of Cancer and the Artic Circle • South – between the Tropic of Capricorn and the Antarctic Circle • In the summer these areas receive warm masses of air from the Tropics • In the winter they receive cold masses of air from the high latitudes

28. Elevation & Climate • The earth’s atmosphere becomes thinner as altitude increases • Thinner air retains less heat • As elevation decreases, temperatures decrease • This effect occurs at all latitudes

29. Wind Wind & water combine with the sun to affect earth’s weather and climate Wind is air that moves across the face of the earth It occurs because the sun heats up the earth’s atmosphere and surface unevenly

30. What causes wind? • Rising warm air creates areas of low pressure • Falling cool air causes areas of high pressure • Cool air then flows in to replace the warm rising air • These movements over the earth’s surface cause winds • Winds distribute the sun’s heat around the planet

31. Wind Patterns • Prevailing Winds are global winds which blow in fairly, constant patterns • Their direction is determined by latitude and is affected by the earth’s movement • Earth rotates to the east, therefore global winds are displaced clockwise in the N. Hemisphere and counterclockwise in the S. Hemisphere • This is called the Coriolis Effect

32. Horse Latitudes • Equator: global winds are diverted north and south which leaves a narrow, windless zone called the doldrums • Horse Latitudes got their name from sailors who would toss cargo from their ships in order to get their ships to sail

33. Ocean Currents • Currents are cold and warm streams of water • They are caused by the earth’s rotation, changes in air pressure, and differences in water temperature • The Coriolis Effect also takes place in the ocean • Currents move clockwise in the N.H. and counterclockwise in the S.H.

34. Ocean Currents • Ocean currents affect climate in the coastal lands • Cold ocean currents cool the lands they pass • Warm ocean currents bring warmer temperatures

35. Weather & the Water Cycle • Wind & water work together to affect weather • Condensation creates precipitation • Water vapor forms in the atmosphere from evaporated surface water • Colder temperatures cool the rising moist air • Then the vapor condenses into liquid droplets to form clouds

36. Landforms & Climate • The surface of the earth can also be affected by climate • Large bodies of water are slower to heat and to cool than land • Water temperatures are more uniform and constant than land temperature, this means their temperature changes slowly

37. Landforms & Climate • Mountain ranges also influence precipitation and affect climate • Winds that blow over an ocean are pushed upward when they meet a mountain range • Rising air cools and release most of its moisture in the form of precipitation • It does this on the windwardside – the side of the mountain range facing the wind

38. Landforms & Climate • After precipitation is released, winds become warmer and drier when they come down on the opposite side of the mountain, or leeward side • Hot, dry air produces little precipitation in an effect known as a rain shadow • This causes dry areas to develop on the leeward side of mountain ranges

39. World Climate Patterns Chapter 3 – Section 3

40. Climate Regions • Geographers divide the earth into climate regions: • Tropical • Dry • Mid-Latitude • High Latitude • Highlands • Each of the subdivisions has its own characteristic soils and natural vegetation • The plant life that grows in an area where the natural environment is unchanged by human activity

41. Tropical Rain Forest They are found in or near low latitudes – the Tropics Tropical rain forest and tropical savanna are the 2 most widespread kinds of climate regions Tropical rain forest climates have an average temperature of 80ºF Yearly rainfall averages about 80 inches

42. Tropical Climates Lush vegetation is common and grows thickly in layers Teak or mahogany trees form a canopy over smaller trees On the floor we have plants that grow under the shade The Amazon River Basin is the world’s largest tropical rain forest

43. Tropical Savanna These areas have dry winters and wet summers They also have high year-round temperatures During the dry season the ground is covered with clumps of coarse grass There are fewer trees than in the rain forests They can be found in Africa, Central & South America, and Australia

44. Dry Climates • There are 2 types of dry climates • Desert • Steppe

45. Deserts These are areas with sparse plant life Yearly rainfall very rarely exceeds 10 inches Temperatures vary from the heat of the day to the cool of night & from season to season

46. Dry Climates • In some desert areas, underground springs may support an oasis • This is an area of lush vegetation • Some deserts have dunes or rocky surfaces and others have fertile soil

47. Steppes They are dry, largely treeless grasslands and they border deserts Yearly rainfall averages 10 to 20 inches The largest steppe stretches eastern Europe and western and central Asia They are also found in North America, South America, Africa, and Australia

48. Mid-Latitudes Climates • They include 4 temperate climate regions • Marine west coast • Mediterranean • Humid subtropical • Humid continental • They experience variable weather patterns and seasonal changes • They give rise to a variety of natural vegetation

49. Marine West Coast Between the latitudes of 30º & 60º north and south Ex: Pacific coast of N. America, much of Europe, parts of S. America, Africa, Australia and New Zealand Abundant rainfall supports the growth of both coniferous and deciduous trees

50. Coniferous Coniferous – trees such as evergreens have cones, needle-shaped leaves, and keep their foliage throughout the winter