1. Oceans & El Nino Ocean-atmosphere coupling matters

2. Key Points u Climate & ocean-atmosphere coupling –Seasonal heating stored in upper layers of ocean –Evaporation of water to atmosphere increases with temperature u The Ocean Circulation u El Niño, La Niña u Other Fluctuations

3. Evaporation u Increases with temperature

4. Schematic Layers in the Ocean Temperature 3700 m 100 m Mixed layer Deep ocean 0 m Horel and Geisler: Figure 4.5 u Deep water is cold and dense u Surface warmed by sunlight and mixed by wind

5. The Principal Links for Climate u Sea Surface Temperature 9/24/98 u Winds – Courtesy WGBH

6. Sea Surface Temperature u From Geostationary Satellite January, 1999

7. Key Points u Climate & ocean-atmosphere coupling u The Ocean Circulation –Ocean basins 4 - 5 km deep –Filled with cold dense water from polar regions –Warmed from above in tropics and mid latitudes –Surface layers mixed by wind and seasonal cooling –Deep ocean overturns slowly ( ~ 2000 yr) u El Niño, La Niña u Other Fluctuations

8. Schematic Ocean Circulation Horel and Geisler: Figure 4.6 Ocean surface Ocean bottom Low latitudesHigh latitudes Mixed layer UpwellingDownwelling u residence time 2000 years

9. Conveyor Belt u A schematic view of the global ocean circulation Horel & Geissler after Broecker

10. Key Points u Climate & ocean-atmosphere coupling u The Ocean Circulation u El Niño, La Niña –Fluctuations every few years in equatorial Pacific –Feedback: ocean surface temperature ->atmospheric convection -> winds ->ocean currents -> temperature –Causes droughts and floods world wide u Other Fluctuations

11. Equatorial Pacific Sea SurfaceTemperature u El Nino u Normal u La Nina Dec 97 Dec 90 Dec 88 u NOAA/PMEL

12. El Nino Years

13. El Nino or La Nina? u El Nino : – Eastern and Central Pacific WARM – Indonesian rain area moves EAST – Coastal Andes: F Ocean: NO UPWELLING F Land: F LOODS u La Nina : – Eastern and Central Pacific COLD – Indonesian rain area NORMAL – Coastal Andes: F Ocean: UPWELLING F Land: VERY DRY

14. The El Nino Feedback u u Ocean-atmosphere coupling u u Slackening trade winds cause surge in upper ocean water along equator u u Ocean temperature anomalies persist for many months u u SST anomalies change atmospheric circulation and trade winds

15. Ocean Atmosphere - Normal – Courtesy NOOAA/PMEL

16. Ocean Atmosphere - El Nino – Courtesy NOOAA/PMEL

17. Associations of El Nino - 1

18. Associations of El Nino - 2

19. Consequences u Warm/cold winters u Floods u Droughts

20. Vegetation Stress u El Nino (top) u La Nina (bottom)

21. A TAO Buoy u Pacific Marine Environmental Laboratory

22. Current Status 10/11/00 u In between. Neither El Niño nor La Niña u TAO Array TAO Array

23. Current Status 2/13/00 u La Nina persists National Oceanic and Atmospheric Administration

24. A historical perspective u Sea Surface Temp- erature u Strength of trade winds PMEL

25. Key Points u Climate & ocean-atmosphere coupling u The Ocean Circulation u El Niño, La Niña u Other Fluctuations –Pacific Decadal Oscillation F Salmon catches, Alaska - California –North Atlantic Oscillation F Rainfall in Sahel F Drought in N.E. Brazil

26. Pacific Decadal Oscillation u Warm u u Cool Mantua et al

27. Selected Pacific Salmon Catches u Mantua et al Mantua et al u Black Warm PDO u Grey Cool PDO

28. Key Points u Climate & ocean-atmosphere coupling u The Ocean Circulation u El Niño, La Niña u Other Fluctuations

29. Sources of Information u Horel & Geisler Chapter 3, 4 u http://www.pmel.noaa.gov/toga-tao/el-nino u http://www.sacbee.com/news/projects/gatheri ng_storm/day1.html u http://www.check6.com u http://www.iphc.washington.edu:80/PAGES/I PHC/Staff/hare/html/papers/pdo/PDO.html