Climate

1. Chapter 18 Climate

2. CLIMATE • General conditions of temp & precipitation for an area over a long period of time. • Southwest US – hot, dry all year.

3. Climate of a region is determined by: 1. Temperature 2. Precipitation

4. FACTORS THAT AFFECT TEMP • Latitude- measure of the distance N & S of equator. Closer to equator, more direct sunlight, warmer climate. Farther away from equator, less sunlight, cooler climate.

5. 2. Elevation- as elevation increases, air cools & can’t hold as much moisture so temp decreases.

6. OCEAN CURRENTS

7. 3. Ocean Currents- a river of water that flows in a definite path in the ocean. The surface temp of water affects the temp of the air.

8. Warm water currents travel away from equator. • Cold water currents travel toward the equator. • Land near currents is affected by the temp of the ocean currents.

9. 4. Distances From Water • Oceans greatly moderate the temps of nearby land. • Water heats/cools slower than land.

10. FACTORS THAT AFFECT PRECIPITATION • Prevailing Winds- Carries different amounts of moisture which affects precipitation.

11. Winds that blow from sea to land carry more moisture. • Places in the center of a land mass have dry climates.

12. DESERT • Region that receives less than 25cm of precipitation in one year.

13. 2. MOUNTAIN RANGES • Act as barriers to winds • Mountains cause air to rise • 2 parts of a mountain: windward side & leeward side

14. A) Windward side- receives a lot of precipitation. Faces the wind. B) Leeward side- drier air. Faces away from wind.

15. How Mtns. Affect Precip. • Air is forced up. As it rises, it starts to cool. • Cold air can’t hold as much moisture so precipitation occurs on the windward side. • Air that comes over the Mtn. (leeward side) is drier.

16. 3. SEASONAL WINDS • Monsoon- a major landbreeze or seabreeze that changes direction with the seasons.

17. THE SEASONS • Most places outside the tropics have 4 seasons: summer, fall, winter, & spring.

18. Causes of Seasons Tilted Axis- the tilt of the earth’s axis as the earth travels around the sun. Tilted on an angle of 23.5

19. The north end of the axis is pointed away from the sun for part of the year (Winter)& toward the sun for another part of the year (Summer).

21. In summer, N. hemisphere is tilted towards the sun = more direct sunlight, warmer temps. (June) • In the winter, N. Hemisphere is pointed away from sun = less sunlight, colder temps. (December)

23. Sec. 2 Climate Regions

24. CLASSIFICATION • Climates are classified according to: 1. Temperature 2. Precipitation

25. 6 Main Climate Regions • Tropical rainy • Dry • Temperate marine • Temperate continental • Polar • Highlands

26. 1. Tropical Rainy Climates • Found in low-lying lands near equator. • 2 types: Tropical Wet, & Tropical Wet-&-Dry.

27. Tropical Wet • Hot/Humid, many rainy days, over 10meters/year. • Windward side of Hawaii • Rain Forest- forests in which large amounts of rain fall year-round.

28. Tropical Wet & Dry • Hot, receives slightly less rain & has a distinct dry & rainy season. • Savannas- tropical grassland • Southern Florida

29. 2. Dry Climates • A climate is dry if the amount of precipitation that falls is less than the amount that evaporates. • Arid Climate & Semiarid Climate.

30. Arid Climate • Desert, with little precipitation (less than 25cm/year). • Hot, sandy & cold or rocky • Parts of California & Southwest.

31. Semiarid Climate • Dry but receives 25-50cm of precipitation/year. • Steppe- dry region that gets enough rainfall for short grasses & bushes to grow. • Great Plains

32. 3. Temperate Marine Climate • Along the coasts of temperate continents • Humid (50F+) in summer & mild winters (20F to 64F). • Mediterranean, Humid Subtropical, Marine West Coast.

33. Mediterranean • Coastal climate that is drier & warmer than West Coast Marine. • Mild winters, cool summers, & moderate rainfall. (agriculture) • Southern California,

34. Marine West Coast • Warm, dry summers & rainy winters • Northern California to Southern Alaska • Because of heavy precipitation, thick forests growhere.

35. Humid Subtropical • Hot/Humid summers & cool winters. Warm & wet. • Southeast US • Forests, oranges, peaches, sugarcane.

36. 4. Temperate Continental Climate • Only found on continents in the Northern Hemisphere. • Not influenced by oceans- you get extreme temps. • 50F or above to 20F or below

37. Humid Continental • Hot, humid summers & cold winters with moderate precipitation year round. • NE United States, Mid West US.

38. Subarctic • Short, cool summers & long, cold winters with light precipitation. • Eastern Alaska, Canada

39. 5. Polar Climate • Coldest climate, Avg. temps below 50F in warmest month. • Includes North & South Poles, Icecaps, & tundras.

40. Tundra • Stretches from northern Alaska, Canada, & Russia. • Short cool summers, bitterly cold winters.

41. PERMAFROST • Permanently frozen land, water cannot drain away so the soil is wet & boggy in summer. • No trees, but moss/grass/shrubs grow.

42. 6. Highlands Climate • Cooler & wetter than nearby lowlands. • Temp decreases with altitude. • Short summers, long, severe winters. NW US.

43. Sec. 3 Long-Term Changes

44. Studying Climate Changes • If plants or animals today need certain conditions to live, then similar plants & animals in the past also required those conditions.

45. Types of Evidence to Study Climate Changes • Fossil evidence • Tree rings • Pollen

46. Tree Rings • Scientists study the pattern of thick or thin tree rings to tell about warm/cool or wet/dry climate.

47. Ice Ages • Cold periods, Glacial episodes. • Huge sheets of ice (glaciers) cover large parts of the Earth’s surface.

48. Last Ice Age was 10,500 yrs ago. Sheets of ice covered N Europe, & North America as low as Indiana & Iowa. • A lot of water was frozen causing ocean level to drop.

49. CAUSES OF CHANGE • Earth’s position • Solar energy input • Volcanic Activity • Movement of Continents

50. Section4