4. Evaporation from the ocean Transport through the atmosphere Condensation and precipitation Return to the ocean Many smaller sub cycles

6. Clouds form when air masses are cooled to their dew point Generally cooled by upward movement Cloud formation depends on atmospheric stability

7. Stable atmosphere lifted parcel of air to cooler (and denser) than surrounding air lifted parcel returns to the original level

8. Unstable atmosphere lifted parcel of air is warmer (and less dense) than surrounding air Moved to a higher level, it will continue to rise “thermals”

9. Rising moist air cools and eventually reaches the dew point Droplets condense around condensation nuclei in saturated air no condensation nuclei: supersaturated air

10. In a state of atmospheric instability, a parcel of air will always be warmer, and therefore less dense, than the surrounding air at any altitude. The parcel will, therefore, continue on in the direction pushed when the upward force is removed. In a state of atmospheric stability, the parcel of air will always be cooler, and therefore more dense, that he surrounding air at any altitude. It will, therefore, return to the original level when the upward force is removed.

11. Cooling of rising air slowed by release of latent heat of vaporization Huge numbers of droplets appear as clouds

12. Precipitation Water returning to Earth’s surface Dew and frost are surface processes, not precipitation

13. Precipitation forms in two ways Coalescence of cloud droplets Growth of ice crystals

14. Coalescence process takes place in warm cumulus clouds, near the tropic oceans clouds contain giant salt condensation nuclei

15. Ice-crystal process Takes place in clouds of middle latitudes Ice crystals capture nearby water molecules and grow Fall as snow in the winter; melt and turn to rain in summer

16. Idealized model Region 10 o N and 10 o S of equator receives more direct solar energy Air heats up, rises and spreads toward poles

17. Air cools and becomes more dense as it rises sinking back to the surface at latitudes 30 o N and 30 o S

18. End Result Band of low pressure near the equator, bands of higher pressure 30 o N and 30 o S of the equator Large convective cells form to equalize pressure

19. Large, horizontally uniform bodies of air Moisture and temperature conditions nearly the same

20. Four main types Continental polar Maritime polar Continental tropical Maritime tropical

21. Dictate air mass weather weather conditions remain the same over several days weather changes when a new mass moves in or when the air mass acquires local conditions

22. Boundaries between air masses at different temperatures Cold front cold air mass moves into and displaces warmer air upward moist rising air cooled

23. Warm front Warm air mass advances over a cooler air mass Long, gently sloping front Clouds and rain may form in advance of the front

24. Stationary front Forces influencing warm and cold air masses become balanced

28. Mechanisms Bulges or waves often form between air masses Overriding, uplifted cold air produces a low pressure area

29. Further cold front motion leads to an occluded front and a cyclone storm Cyclone Low pressure area with inflowing, upward force winds

30. Circulation pattern caused by the Coriolis effect Anti-cyclone High pressure area Air sinks, is warmed, relative humidity is lowered

34. Rapid, violent weather changes Often associated with frontal passage

35. Three major types thunderstorms tornadoes hurricanes

36. Usually develops in warm, very moist, and unstable air Three stages Cumulus – associated with convection, mountain barriers, or a cold front

37. Mature Updraft can no longer support growing ice crystals and snow flakes Falling frozen water melts and becomes rain Hail formed through ice accumulation cycles

38. Final All updrafts are exhausted

40. Updrafts, downdrafts and circulating precipitation separate electrical charges Charges accumulate in different parts of the thunderhead

41. Lightning Discharge between charge centers Can be cloud to ground, ground to cloud, or cloud to cloud Expanding pressure wave from heated air produces crack of thunder

43. Smallest, most violent weather disturbance Rapidly whirling column of air diameter of 100-400 meters wind speeds up to 480 km/h

44. Damage produced high winds drop in pressure at center flying debris Associated with intense thunderstorms

48. Tropical depression Tropical Storm Hurricane

49. Tropical depression area of low pressure winds generally moving at 55 mph or less

50. Tropical storm more intense low pressure areas Winds between 56 and 120 mph

51. Hurricanes Very intense low pressure Winds in excess of 120 km/h Fully developed hurricane has a calm eye surrounded by intense rain and thunderstorms

52. Based upon mathematical models of the atmosphere Billions of calculations necessitate use of supercomputers

53. Fairly accurate forecasts up to three days possible Major uncertainty:insufficient technology to connect small and large scale events Ultimately oceanic influences need to be better understood

54. Composite, larger weather patterns occurring over a number of years.

55. Determining factor in types of plants and animals in a given location types of houses built lifestyles

56. Influences shape of the landscape types of soil agricultural type and productivity

57. Two primary factors 1.Intensity of incoming solar radiation 2.Number of daylight hours

58. Low altitudes High solar radiation Yearly variation small Temperature uniformly high

59. Middle latitudes Higher solar radiation during one part of the year; lower during the other Overall temperatures lower with greater variation than low latitudes

60. High latitudes Maximum amount of radiation during one part of the year; none in the other Overall temperatures are lowest with violent variation

62. Defined in terms of yearly temperature averages

63. Tropical climate zone near equator receives most solar radiation hot

64. Polar climate zone least solar radiation cold constant daylight part of summer; constant darkness part of winter

65. Temperate climate zone intermediate between others

68. Four Major Factors

69. Altitude Higher altitude air radiates more energy into space

70. Mountains Cooler air at higher altitudes Upwind slopes receive more precipitation; downwind slopes receive less

71. Large bodies of water high specific heat of water moderates temperature changes

72. Ocean currents can bring water nearby that has a different temperature that the land

74. Problems No sharp boundaries No two places have exactly the same climate

78. Marine climate Near ocean Influenced mostly by air masses from the ocean Can be polar or tropical

79. Continental climate far from ocean influenced mostly by air masses from large land areas can be polar or tropical

80. Other classifications: arid semiarid humid

81. Microclimate: a local pattern in climate Can be associated with large cities