Chapter: Climate

1. Table of Contents Chapter: Climate Section 1: What is climate? Section 2: Climate Types Section 3: Climatic Changes

2. What is climate? 1 Climate • Climate is the pattern of weather that occurs in an area over many years. It determines the types of plants or animals that can survive, and it influences how people live. • Climate is determined by averaging the weather of a region over a long period of time, such as 30 years.

3. What is climate? • The tropics—the region between latitudes 23.5°N and 23.5°S—receive the most solar radiation because the Sun shines almost directly over these areas. 1 Latitude and Climate • Latitude, a measure of distance north or south of the equator, affects climate.

4. What is climate? 1 Latitude and Climate • The polar zonesextend from 66.5°N and 66.5°S latitude to the poles. Solar radiation hits these zones at a low angle, spreading energy over a large area. • Polar regions are never warm.

5. What is climate? 1 Latitude and Climate • Between the tropics and the polar zones are the temperate zones. Temperatures here are moderate. Most of the United States is in a temperate zone. Take 3 minutes to draw this image in your notes: Label the latitudes and zones associated with those latitudes

6. What is climate? 1 Other Factors— Large Bodies of Water • It takes a lot more heat to increase the temperature of water than it takes to increase the temperature of land. • In addition, water must give up more heat than land does for it to cool.

7. What is climate? 1 Other Factors— Large Bodies of Water • Large bodies of water can affect the climate of coastal areas by absorbing or giving off heat.

8. What is climate? 1 Ocean Currents • Ocean currents affect coastal climates. • Warm currents begin near the equator and flow toward higher latitudes, warming the land regions they pass.

9. What is climate? 1 Ocean Currents • When the currents cool off and flow back toward the equator, they cool the air and climates of nearby land. • Winds blowing from the sea are often moister than those blowing from land. Therefore, some coastal areas have wetter climates than places farther inland.

10. What is climate? 1 Mountains • At the same latitude, the climate is colder in the mountains than at sea level. • When radiation from the Sun is absorbed by Earth’s surface, it heats the land.

11. What is climate? • Because Earth’s atmosphere gets thinner at higher altitudes, the air in the mountains has fewer molecules to absorb heat. 1 Mountains • Heat from Earth then warms the atmosphere.

12. What is climate? 1 Rain Shadows • On the windward side of a mountain range, air rises, cools, and drops its moisture. • On the leeward side of a mountain range air descends, heats up, and dries the land.

13. What is climate? 1 Cities • Streets, parking lots, and buildings heat up, in turn heating the air. • Air pollution traps this heat, creating what is known as the heat-island effect. • Temperatures in a city can be 5°C higher than in surrounding rural areas.

14. Section Check 1 Question 1 The pattern of weather that occurs in an area over many years is called that area’s __________. A. atmosphere B. climate C. hemisphere D. zone

15. Section Check 1 Answer The answer is B. Climate determines the types of plants or animals that can survive in an area; it also as influences how people live.

16. Section Check 1 Question 2 The region between latitudes 23.5º N and 23.5º S is the __________. A. arctic B. polar zone C. temperate zone D. tropics

17. Section Check 1 Answer The answer is D. The tropics receive the most solar radiation and have temperatures that are always hot, except at high elevations.

18. Section Check 1 Question 3 According to this figure, most of the United States is in __________. A. a polar zone B. a temperate zone C. the Tropic of Cancer D. the Tropic of Capricorn

19. Section Check 1 Answer The answer is B. Most of the United States is in a temperature zone, between the tropics and the polar zone.

20. Climate Types 2 Classifying Climates • Climatologists—people who study climates—usually use a system developed in 1918 by Wladimir Köppen to classify climates. • Köppen observed that the types of plants found in a region depended on the climate of the area. • He classified world climates by using the annual and monthly averages of temperature and precipitation of different regions.

21. Climate Types 2 Classifying Climates • The climate classification system separates climates into six groups—tropical, mild, dry, continental, polar, and high elevation.

22. Climate Types 2 Classifying Climates

23. Climate Classification System • What is the most widely used and best known? • Koppen Climate Classification System • Uses monthly values of temperature and precipitation to classify climates • Classifies climate regions in a realistic way • It has 5 principal groups- What are they? (hint pg 592)

24. How are climate classified? • All of them are classified by temperature EXCEPT…. • Dry climates • Dry climates are classified by amount of precipitation that falls over an area

25. Pages 593-599 • What are Humid Tropical Climates, Humid Mid- Latitude Climates and Dry Climates? • Fill in the blanks: • 1. World Climates • A. Humid tropical • Wet tropics • B Humid mid-latitude • C Dry

26. Climates • Table 1- Wet Tropical • Table 2- Tropical Wet and Dry • Table 3- Humid Mid – Latitude (mild winters) • Table 4- Humid Mid – Latitude (severe winters) • Table 5- Polar Climates • Table 6- Highland Climates

27. Assignment • Read about your climate and make notes of the key ideas in the text. • I will call on a representative of your table to share with the class

29. Map Master • Page 594-595 (Sahara = northern Africa) • Do the map master skills activity • Answer the following: • Name 3 places that have severe winters • Name 4 places that have arid climates • What climate does NC have? • Pick a place to go on vacation that would have a tropical wet and dry climate.

30. Worldwide Climate Zone Activity Objective: • To identify the Earth’s climate zones by isotherm boundaries • To analyze a map of the Earth’s climate zones

31. Section Check 2 Question 1 What two factors do climatologists use to classify climates?

32. Section Check 2 Answer Climatologists use a system developed by Wladimir Koppen that classifies climates using average temperatures and precipitation.

33. Climatic Changes 3 Earth’s Seasons • Seasons are short periods of climatic change caused by changes in the amount of solar radiation an area receives. • Because Earth is tilted, different areas of Earth receive changing amounts of solar radiation throughout the year.

34. Climatic Changes 3 Seasonal Changes • Because of fairly constant solar radiation near the equator, the tropics do not have much seasonal temperature change. • The middle latitudes, or temperate zones, have warm summers and cool winters. Spring and fall are usually mild.

35. Climatic Changes 3 High Latitudes • The high latitudes near the poles have great differences in temperature and number of daylight hours. • During summer in the northern hemisphere, the north pole is tilted toward the Sun.

36. Climatic Changes 3 High Latitudes • During summer at the north pole, the Sun doesn’t set for nearly six months. • During that same time, the sun never rises at the south pole.

37. Climatic Changes 3 El Niño and La Niña • El Niño(el NEEN yoh) is a climatic event that involves the tropical Pacific Ocean and the atmosphere. • During normal years, strong trade winds that blow east to west along the equator push warm surface water toward the western Pacific Ocean. • During El Niño years, these winds weaken and sometimes reverse.

38. Climatic Changes 3 El Niño and La Niña • The change in winds allows warm, tropical water in the upper layers of the Pacific to flow back eastward to South America. • Ocean temperatures increase by 1°C to 70°C off the coast of Peru. • El Niño can affect weather patterns. • It can alter the position and strength of one of the jet streams.

39. Climatic Changes 3 El Niño and La Niña • The opposite of El Niño is La Niña. • During La Niña, the winds blowing across the Pacific are stronger than normal, causing warm water to accumulate in the western Pacific.

40. Climatic Changes 3 El Niño and La Niña • La Niña may cause droughts in the southern United States and excess rain fall in the northwestern United States.

41. Climatic Changes 3 Climatic Change • Some warm-weather fossils found in polar regions indicate that at times in Earth’s past, worldwide climate was much warmer than at present. • At other times Earth’s climate has been much colder than it is today.

42. Climatic Changes 3 Climatic Change • Sediments in many parts of the world show that several different times in the past 2 million years, glaciers covered large parts of Earth’s surface. • These times are called ice ages. • During the past 2 million years, ice ages have alternated with warm periods called interglacial intervals. • We are now in an interglacial interval that began about 11,500 years ago.

43. Climatic Changes • Catastrophic events, including meteorite collisions and large volcanic eruptions, can affect climate over short periods of time, such as a year or several years. 3 What causes climatic change?

44. Climatic Changes 3 What causes climatic change? • Another factor that can alter Earth’s climate in short- or long-term changes in solar output, which is the amount of energy given off by the Sun. • Changes in the Earth’s movements in space affect climate over many thousands of years, and movement of Earth’s crustal plates can change climate over millions of years.

45. Climatic Changes 3 Atmospheric Solids and Liquids • Small solid and liquid particles always are present in Earth’s atmosphere. • Some ways that particles enter the atmosphere naturally include volcanic eruptions, soot from fires, and wind erosion of soil particles. • Humans add particles to the atmosphere through automobile exhaust and smoke stack emissions. • These small particles can affect climate.

46. Climatic Changes • During the eruption, particles were spread high into the atmosphere and circled the globe. Over time, particles spread around the world, blocking some of the Sun’s energy from reaching Earth. 3 Atmospheric Solids and Liquids • Mount Pinatubo in the Philippines erupted in 1991.

47. Climatic Changes 3 Energy from the Sun • If the output of radiation from the Sun varies, Earth’s climate could change. • Some changes in the amount of energy given off by the Sun seem to be related to the presence of sunspots. • Sunspots are dark spots on the surface of the Sun. • An extremely cold period in Europe occurred between 1645 and 1715. During this time, very few sunspots appeared on the Sun.

48. Climatic Changes 3 Earth Movements • Earth’s axis currently is tilted 23.5° from perpendicular to the plane of its orbit around the Sun. • In the past, this tilt has increased to 24.5° and has decreased to 21.5° • When this tilt is at its maximum, the change between summer and winter is probably greater.

49. Climatic Changes 3 Earth Movements • Two additional Earth movements also cause climatic change. • Earth’s axis wobbles in space just like the axis of a top wobbles when it begins to spin more slowly. • This can affect the amount of solar energy received by different parts of Earth. Also, the shape of Earth’s orbit changes.

50. Climatic Changes 3 Amount of Solar Energy • These movements of Earth cause the amount of solar energy reaching different parts of Earth to vary over time. • These changes might have caused glaciers to grow and shrink over the last few million years.