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Circulation in the atmosphere Lecture 06 Circulation in the Atmosphere.

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Presentation on theme: "Circulation in the atmosphere Lecture 06 Circulation in the Atmosphere."— Presentation transcript:

1 Circulation in the atmosphere Lecture 06 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 What regulates the motion of fluid particles in the ocean and atmosphere? Newton’s Law

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

5

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

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

8

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

10 Non rotating view of Atmospheric Circulation

11 Hurricane IVAN L H H H H

12 North Hemisphere A B t1t1 t2t2 t3t3 t4t4 t5t5 F pressure F Coriolis Rate of Rotation High Pressure Low Pressure

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

14 North Hemisphere A B t1t1 t2t2 t3t3 t4t4 t5t5 F pressure F Coriolis Rate of Rotation High PressureLow Pressure

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

16 Fig.6-3

17 F pressure F Coriolis F pressure F Coriolis F pressure F Coriolis F pressure F Coriolis When this balance is reached the movement of the particles (and therefore of the flow) is called geostrophic motion

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

19 F pressure F Coriolis 1)Particle will have the Coriolis force 90 degrees to the right 2)Particles will tend to move along line of constant pressure 3)Particles will have the high pressure on their right (same as Coriolis) Some practical rules to remember: High Pressure Low Pressure

20 Hurricane IVAN L H H H H F pressure F Coriolis

21 Vortices in N.H. L F pressure F Coriolis H F pressure High Pressure System Low Pressure System

22 Vertical view of the atmosphere Equator Pole

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

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

25 Midlatitude Cyclones (N.H.)

26 Poleward Heat Transport

27

28

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 Westerlies Easterlies (Trades) Redistribution of Heat – Large scale convective Cells

34 Rotation effects, the Coriolis Force

35 F pressure F Coriolis 1)Particle will have the Coriolis force 90 degrees to the right 2)Particles will tend to move along line of constant pressure 3)Particles will have the high pressure on their right (same as Coriolis) Some practical rules to remember: High Pressure Low Pressure

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

37 Circulation in the atmosphere Problem?

38 Role of Friction

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

40 Circulation in the atmosphere Diagram of Atmospheric Circulation

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

42 Role of Friction on synoptic scales

43 Vortices L F pressure F Coriolis H F pressure High Pressure System Low Pressure System

44

45 Hurricane IVAN L H H H H F pressure F Coriolis

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 Westerlies Easterlies (Trades)

51 A look at the atmospheric circulation from space http://www.atmos.washington.edu/~ov ens/loops/wxloop.cgi?wv_moll+/14d/ Advection of water vapour associated with Eastrerlies and Westerlies Strong convection over tropical region Generation of Tropical Cyclones

52 equator

53 ITCZ: Inter-Tropical Convergenze Zone

54 Midlatitude Instabilities http://www.atmos.washington.edu /~ovens/loops/wxloop.cgi?ir_centr al+/48h/3h

55 Warm Front Cold Front Tropical Air Polar Air Tropical Air

56 Tropical Cyclones Webster P.J, G. J. Holland, J. A. Curry, H.-R. Chang (2005) Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment, SCIENCE Emmanuel, K. (2004) Increasing destructiveness of tropical cyclones over the past 30 years, NATURE Articles RITA http://www.atmos.wash ington.edu/~ovens/loop s/wxloop.cgi?fronts_ir_e ast+/48h/ http://www.atmos.wash ington.edu/~ovens/loop s/wxloop.cgi?fronts_ir_e ast+/48h/

57 L F pressure F Coriolis

58 Why do tropical storms intensify?

59 Vortices L F pressure F Coriolis H F pressure High Pressure System Low Pressure System

60

61 Tropical cyclone have an eye of anticyclonic circulation!

62 Storm Surge: sea level rises because of the low atmospheric pressure system

63 Vertical view of the atmosphere and Poleward Transport of Heat Equator Pole Hadley Cell Ferrel Cell Polar Cell They are the views of zonal average circulations

64 Radiative Budget

65

66 Rotation effects are not always important

67 Land-Sea Breeze

68 Moonsoons, a continental scale land-sea breeze


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