1. The Atmosphere Wind Field –Drives upper layer flows of the major gyres Net Heat & Freshwater Exchanges –Drives buoyancy flows (like the conveyor belt) Chapter 2 - Ocean Circulation (we will skip parts)

2. Stupid things that drive Dave crazy... Easterly winds are from the east (to the west) Westward winds are to the west (from the east) Oceanographers say westward winds Meteorologists say easterly winds –I’m right...

4. Major Features of the Global Wind Field Trades to Westerlies to Easterlies (toward poles) Convergence of trades leads to ITCZ –Ascending moist air at equator –Drying & subsidence leads to a high over the subtropical ocean Polar front is another region of convergence

5. Global Wind Field

6. Hadley Cells

8. Major Features of the Global Wind Field Winds blow from high to low pressure BUT Earth rotation turns them to the right (left) in the northern (southern) hemisphere Hence, winds are mostly zonal (along zones of constant latitude)

9. Earth Rotation Earth’s rotation gives rise to a fictitious force called the Coriolis force It accounts for the apparent deflection of motions viewed in our rotating frame Analogies –throwing a ball from a merry-go-round –sending a ball to the sun

10. Earth Rotation

11. Motions in a rotating frame will appear to deflect to the right (NH) Deflection will be to the right in the northern hemisphere and to the left in the southern No apparent deflection right on the equator

13. Real Winds Real winds are not zonal –Land masses mess this up Seasonal changes happen –intensification in high latitudes –monsoons

14. July climatology

15. January climatology

16. Real Winds Location of ITCZ shifts seasonally Seasonal changes in the monsoon –SW in July –NE in January Driven in large degree by greater seasonal heating on the land

17. Cyclones/Anticyclones Mid-latitude storms do most of the atmospheric heat transport Cyclones –low pressure & CCW (NH) rotation Anticyclones –high pressure & CW rotation

18. Cyclones/Anticyclones CycloneAnticyclone

19. Cyclones/Anticyclones Combination of cyclones & anticyclones lead to poleward heat transport

20. Cyclones/Anticyclones

22. Air Sea Interactions We’ve seen this. Warming of ocean leads to high SST High SST leads to warm atmosphere Tropics - High SST corresponds to regions of rising moist air