How the surface and high altiude air moves the way it does, the effect of the spin of the earth and the tri-cellular circulation model and the ever confusing ITCZ

1. Atmospheric circulation

2. Global Heat budget Excess at the equator Deficit at the poles Therefore all air and ocean currents transport heat pole wards

4. If there was no land on earth, we would have two big convection cells, one in each hemisphere

5. Remember, air moves from hot to cold and high to low pressure

7. Coriolis This is the effect of the earth spinning. It affects all large bodies of liquid or gas, ie water and air Remember the earth spins anticlockwise if you were looking down on the North Pole, as in from west to east Therefore along the equator, major currents flow from east to west.

8. Hadley cells The helical circulation patterns of which the Trade Winds form the surface expression; the north–south component of this helical circulation is known as the Hadley circulation; the two ‘Hadley cells’ can be seen on either side of the Equator

9. Global Circulation

12. Air pressure systems

13. The ITCZ This stands for the Inter Tropical Convergence Zone It is the junction near the equator where the two Hadley cells land based currents meet It’s position changes with regards to season

16. changing conditions over continent and ocean in a monsoon climate (a) Northern winter: dry, cooled air subsides over the continent, which is a region of high surface pressure; winds blow off the continent picking up moisture from the much warmer ocean and eventually moist air rises at the Intertropical Convergence Zone, causing abundant rain. (b) Northern summer: land is now much warmer than the ocean, so the region of low surface pressure corresponding to the ITCZ and its zone of rain has moved northwards towards the interior of the continent.

17. Orographic Rainfall

18. The Daisy World Hypothesis http://library.thinkquest.org/C003763/flash/gaia1.htm