Air/Sea Interface, Coriolis , and Wind notes

1. Air/Sea Interface, Coriolis, and Wind notes

2. Overview • Atmosphere and ocean one interdependent system • Solar energy creates winds • Winds drive surface ocean currents and waves • Examples of interactions: • El Niño • Currents

3. Intro: So why is the ocean blue • Because blue light penetrates the deepest compared to other colors • Nothing to do with what will talk about today, but it at least mentions the ocean and the atmosphere…

4. So why is the ocean blue

5. Air/Sea Interface • Like land, the oceans can have ‘weather’ as well • Warm, cold, choppy, murky, etc • The common boundary between the atmosphere and the ocean is called the air/sea interface, the place where the atmosphere and ocean meet and interact.

6. Air/Sea • It is through the collision of their molecules (air molecules in the atmosphere and water molecules in the ocean) that the ocean and atmosphere exchange momentum • Wind blowing over the ocean imparts momentum to the ocean surface and causes the ocean to flow or forms waves

7. Air/Sea Exchange • Gases, salts, water, and many other compounds also move across the air/sea interface (think back to your cycles). • They also exchange HEAT

8. Air/Sea • Ultimately all winds are generated by unequal heating of the Earth by the sun. • Parallel rays from the sun hit a round earth, so only at the equator does energy from the sun fall on a flat surface at a right angle to the sun

9. Air/Sea • At the equator, radiation from the sun is particularly intense, and the air above the tropical oceans warms rapidly each day. • When heated, it expands and becomes less dense • Results: moist, hot air rises far above the equator (low pressure)

10. Air/Sea • But expanding air cools and cannot retain moisture… • Instead, water vapor condenses to liquid water, clouds form, and rains fall in the tropics. • The now dry air move north or south as strong upper atmospheric winds blow, convecting heat toward the poles

11. Movements in atmosphere • Air (wind) always moves from regions of high pressure to low • Cool dense air, higher surface pressure • Warm less dense air, lower surface pressure Fig. 6.6

12. Movements in air Non-rotating Earth • Air (wind) always moves from regions of high pressure to low • Convection or circulation cell Fig. 6.7

13. Physical properties of atmosphere • Warm air, less dense (rises) • Cool air, more dense (sinks) • Moist air, less dense (rises) • Dry air, more dense (sinks) Fig. 6.5 Rises = Low pressure Sinks = High Pressure

14. Low & High Pressure Systems • Winds: H L Air movement

15. Low & High Pressure Systems Winds: Air movement H L

16. Low & High Pressure Systems Winds: Air movement H L

17. Low & High Pressure Systems Winds: Air movement H L

18. Low & High Pressure Systems Low and high pressure areas “chase” each other around H L Air movement

19. Air movement Air Movement • What happens to warm air as it rises? • Temperature: • Precipitation: • Density: • Movement:

20. Air movement Air Movement • Warm air rises • Heat makes molecules move more • Further-apart molecules = lower density • Less dense air rises above more dense air • Cold air sinks • Colder molecules move less • Become packed more closely together • Denser cool air sinks below less dense air

21. If this is true, how come the earths wind patterns don’t look like this?

22. Movements in air on a rotating Earth • Coriolis effect causes deflection in moving body • Due to Earth’s rotation to east • Most pronounced on objects that move long distances across latitudes • Deflection to right in Northern Hemisphere • Deflection to left in Southern Hemisphere • Maximum Coriolis effect at poles • No Coriolis effect at equator

23. Coriolis Effect

24. Real Life Application: • a famous example is the shelling of Paris during the First World War by the Germans. The Germans built huge rail-mounted cannons, called the "Long Max" cannons, which had a range of 75 miles. Firing from the northwest of Paris, the Germans kept missing Paris and the shells would land west of Paris, because during the long flight of the shell, Paris had moved eastwards. They had to make corrections for the Coriolis Effect before they could hit their targets.

25. Coriolis Effect The Coriolis Effect • In the Northern Hemisphere: • Objects are deflected to the right • Faster-moving objects are deflected more • Deflection is stronger closer to the poles • In the Southern Hemisphere: • Objects are deflected to the left • Faster-moving objects are deflected more • Deflection is stronger closer to the poles

26. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

27. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

28. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

29. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

30. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

31. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

32. N W E S Coriolis Effect Northern Hemisphere Deflection Equator

33. N W E S Coriolis Effect Southern Hemisphere Deflection Equator

34. N W E S Coriolis Effect Southern Hemisphere Deflection Equator

35. Coriolis Effect Examples: • A plane leaves Myrtle Beach for Montreal, but does not correct for the Coriolis Effect. Where does it wind up in relation to its intended destination? • A plane leaves Myrtle Beach for San Diego, but does not correct for the Coriolis Effect. Where does it wind up in relation to its intended destination?

36. Coriolis Effect Montreal San Diego Aerial Image: NASA

37. Coriolis Effect Montreal San Diego Coriolis Effect Not To Scale Aerial Image: NASA

38. Coriolis Effect Montreal San Diego Coriolis Effect Not To Scale Aerial Image: NASA

39. Due to coriolis , unequal solar heating, and convection, air patterns actually look like this …sort of Fig. 6.10

40. Global Wind Patterns

42. Global atmospheric circulation • Circulation cells circulate as air changes density due to: • Changes in air temperature • Changes in water vapor content • Circulation cells • Hadley cells (0o to 30o N and S) • Ferrel cells (30o to 60o N and S) • Polar cells (60o to 90o N and S)

44. Global atmospheric circulation • High pressure zones • Subtropical highs • Polar highs • Clear skies • Low pressure zones • Equatorial low • Subpolar lows • Overcast skies with lots of precipitation

46. Also referred to as the Horse Latitudes! Ask me why

49. Fig. 6.10

50. Global wind belts • Trade winds • Northeast trades in Northern Hemisphere • Southeast trades in Southern Hemisphere • Prevailing westerlies • Polar easterlies • Boundaries between wind belts (dead zones, NO WIND!) • Doldrums or Intertropical Convergence Zone (ITCZ) • Horse latitudes • Polar fronts