1. Lecture 05a Atmospheric General Circulation Circulation in the atmosphere

2. Learning objects • Review the general model of atmospheric circulation • Explore the basic nature of atmospheric motion on our rotating Earth

3. Newton’s Law What regulates the motion of fluid particles in the ocean and atmosphere?

4. troposphere surface Higher Latitudes Equator/Tropics What drives the circulation of the atmosphere? Heating by the sun  AIR PRESSURE

6. Vertical view of air pressure (global convection) High Pressure Low Pressure High Pressure

7. Horizontal view of air pressure at ocean surface High Pressure + Higher Latitudes Surfaces of constant pressure y (latitude) x (longitude) _ Equator/Tropics Low Pressure

9. Newton’s Law v y (latitude) x (longitude) u Motion across Latitudes Motion along Latitude

10. Non rotating view of Atmospheric Circulation

11. Hurricane IVAN H H L H H

12. t3 t4 t2 t5 t1 Fpressure FCoriolis Rate of Rotation North Hemisphere Low Pressure B A High Pressure

13. Newton’s Law v y (latitude) x (longitude) u Motion across Latitudes Motion along Latitude

14. t3 t4 t2 t5 t1 Fpressure FCoriolis Rate of Rotation North Hemisphere A B High Pressure Low Pressure

15. Newton’s Law v y (latitude) x (longitude) u Motion across Latitudes Motion along Latitude

16. Fig.6-3

17. Fpressure FCoriolis FCoriolis Fpressure Fpressure Fpressure FCoriolis FCoriolis When this balance is reached the movement of the particles (and therefore of the flow) is called geostrophic motion

18. Newton’s Law v y (latitude) x (longitude) u Motion across Latitudes Motion along Latitude

19. Some practical rules to remember: Fpressure Low Pressure High Pressure FCoriolis • Particle will have the Coriolis force 90 degrees to the right • Particles will tend to move along line of constant pressure • Particles will have the high pressure on their right (same as Coriolis)

20. Hurricane IVAN H H L Fpressure H H FCoriolis

21. Vortices in N.H. L H Fpressure FCoriolis FCoriolis Fpressure Low Pressure System High Pressure System

22. Vertical view of the atmosphere Pole Equator

23. Polar High L L Subpolar Low H H H Subtropical High L Eq. Low L L H H H L L

24. Vertical view of the atmosphere and Poleward Transport of Heat Pole Equator

25. Midlatitude Cyclones (N.H.)

26. Poleward Heat Transport

29. The seasonal cycle

30. Differential Heating From Equators to Poles

31. How the ocean responds to the atmospheric wind and how it contributes to the heat transport

32. Important Concepts to remember: Redistribution of Heat Effects of Rotation The role of friction Conservation of angular momentum

33. Schematic depiction of the development of the atmospheric circulation,starting from a state of rest Easterlies (Trades) Westerlies Redistribution of Heat – Large scale convective Cells

34. Rotation effects, the Coriolis Force

35. Some practical rules to remember: Fpressure Low Pressure High Pressure FCoriolis • Particle will have the Coriolis force 90 degrees to the right • Particles will tend to move along line of constant pressure • Particles will have the high pressure on their right (same as Coriolis)

36. Schematic depiction of the development of the atmospheric circulation,starting from a state of rest Easterlies (Trades) Westerlies

37. Problem? Circulation in the atmosphere

38. Role of Friction

39. Schematic depiction of the development of the atmospheric circulation,starting from a state of rest Easterlies (Trades) Westerlies

40. Diagram of Atmospheric Circulation Circulation in the atmosphere

41. Vertical view of the atmosphere and Poleward Transport of Heat Hadley Cell Ferrel Cell Polar Cell Pole Equator

42. Role of Friction on synoptic scales

43. Vortices L H Fpressure FCoriolis FCoriolis Fpressure Low Pressure System High Pressure System

45. Hurricane IVAN H H L Fpressure H H FCoriolis

46. Rotation effects are not always important

47. Land-Sea Breeze

48. Moonsoons, a continental scale land-sea breeze

49. Review of Conservation of angular momentum (a second look) The Atmopsheric Circulation (a view from space and from NWS models) A closer look at Huricanes, their formation and the oceanic response Zonal average circulation Radiative Budget

50. Schematic depiction of the development of the atmospheric circulation,starting from a state of rest Easterlies (Trades) Westerlies