C limate

1. Climate

2. What is Climate? • Climatology - study of earth’s surface climate and the factors that affect the past, present and future climate changes.

4. Climate describes

8. Average Precipitation Patterns

9. U.S. Precipitation Patterns

10. Normals • Data is collected at 1000’s of locations is compiled for over 30 years to establish Normalsor standard values • Must be used with caution Why? • 1) Weather conditions may differ from Normals • 2) Normals not intended to describe usual weather condition • 3) Normals only apply to specific areas

12. What causes Climate?

13. Three main factors

14. Latitudes • Amount of solar radiation varies place to place. Why? Earth is tilted on its axis and it affects how the sun’s rays strike the earth • 23.5 S to 23.5 N - Tropics - receives the most sun . Temperature warm year round • 23.5 N- 66.5 N • 23.5 S- 66.5 S •  Temperate Zone - Temperature Moderate

16. Temperate Zone23.5 N – 66.5 N and 23.5 S – 66.5 N

17. Latitudes cont……. 66.5 N and 66.5 S - polar Zone Sun strikes at low angles/Cold temperatures.

18. Topography Effects • H2O heats up and cools down more slowly than land. Coastal regions are warmer in winter and cooler in the summer than inland areas of similar latitudes. • Temperature in lower atmosphere decreases with altitude. • Orographic lifting - air rises over mountain, rising air cools and condenses then drops moisture.

19. Topography Effect

20. Air Masses • 2 courses of weather movement interactions of air masses - air masses affect climate tool

21. Air masses of N. America

22. Region and Origin • Caused by difference in the amount of solar radiation. Average weather conditions in or near air masses are fairly similar to conditions. Exhibited by air masses.

23. Sun Rays Hitting the earth

24. Sun Rays in relationship to Latitude

25. Climate Classification • How are climates classified? • Based on the climate and precipitation and vegetation • Continental • Polar • High elevations

26. World Climates

27. Tropical Climate - 600 cm of rainfall • Heat + rain = rainforest under the influence of maritime tropical air • Transition zones border the rainy tropics • Tropical wet distinct African Savannas • Tropical dry dry season

28. Dry Climates • Dry Climates - cover 30 % or earth - largest climate zone - where most of the deserts are located: Sahara, Gobies, Australian • Continental Tropical dominates • -low precipitation • -vegetation scarce • -intense solar radiation • -high rate of evaporation - few clouds • -2 subtypes: arid region (deserts) • Semi and steppes

29. Mild Climates • 3 subtypes • - Humid subtropical climate - influenced by subtropical high pressure systems over oceans Southeast of the U.S. • -Marine west coast - dominated by the constant inland flow of • air from ocean- mild winters and cool summers • -Mediterranean - Italy, Spain - summers warm - lack of cool ocean currents in the Mediterranean Sea

30. Polar Climates • Coldest regions on earth - • mean temperature of warmest month is lest than 10°C - • precipitation is low - • cold air does not hold cold moisture. • Amount of heat radiates from earth is low thus there are no convection currents necessary to release precipitation. • Variations - high elevations, includes parts of Andes Mountains of South America

33. Micro Climate- localized climate within a main regional one.

34. Microclimate

35. Heat Islands-climate is warmer than the surrounding rural areas. climate is warmer than the surrounding rural areas.

36. Ice Ages - Earth surface was totally covered by vast sheets of ice. Average global temperature decreased by 5°C sparked the advancement of ice sheets. Interglacial Intervals = alternating of cold/warm periods. • We are now in a interglacial period. Glaciers covered from east to west and as far south as Indiana. • Retreat - scoured the Finger Lakes of New York / Great Lakes - Michigan

37. North America Ice Age coverage

38. Ice Age coverage of the world

39. Europe Ice Age Coverage

40. Seasons • Seasons - short term climate changes caused by regular variations in daylight, temperature and weather patterns. Summer - North Pole titled toward sun - Northern Hemisphere / Southern Hemisphere - winter

41. Why do we Have SEASONS?

42. DEGREE OF INCOMING SOLAR ENERGY

43. SEASONS IN THE LATITUDES

44. El Nino Cont……. • Warm currents that occasionally develops off the western coast of South America normally. • No reason - Trade winds weaken - allows warm winters from the Western Pacific surge eastward towards the South American coast • Convection currents strengthen - Northwest coast of South America becomes warm and wetter. • Jet Stream moves south. Weather system take a southern track - storms in California and Gulf Coast

45. El Nino

46. El Nino Cont…… • + positive effect - strong upper winds keep the tropical disturbances down • Change can be Natural Past climate changes - found studying tree rings, ice core samples, fossils and radioactive carbon.

47. La Nina- Characterized by unusually cold ocean temperatures in the Equatorial Pacific • a. La Niña often causes drought conditions in the western Pacific; flooding in northern South America; mild wet summers in northern North America, and drought in the southeastern United States.

48. La Nina

49. Changes in the earth’s climate is caused by: • 1) Solar activity • 2) Changes in the earth’s tilt • 3) Earth’s orbit • 4) Volcanic eruptions

50. Solar Activity- Sunspots • Low sunspot activity - Maunder Minimum (“Little Ice Age”) cold dramatic conditions. • High sunspot activity - Temperatures are warmer - Earth’s orbit - shape of the earth’s elliptical orbit changes and becomes more elliptical than circular. • If the orbit elongates the earth is closer to the sun. Temperature is cooler. • The earth’s tilt is 25.3° and it tends to vary from 22.1° to 24.5° every 41,000 years. • Changes in the tilt causes seasons to be more severe - winters-warmer, summers cooler. Colder weather causes ice sheets to expand causes ice age