institute.nsta/web_seminars.asp

1. LIVE INTERACTIVE LEARNING @ YOUR DESKTOP NOAA/NSTA Web Seminar: The Ocean’s Role in Weather and Climate http://institute.nsta.org/web_seminars.asp

2. The influence of the Atlantic ocean on climate, from Atlantic hurricanes to African droughtThomas L. DelworthGeophysical Fluid Dynamics Laboratory/NOAAPrinceton, NJ • Outline: • Basics of the Atlantic Ocean • Multidecadal changes in the Atlantic: impact on climate • African drought • Conditions for tropical storms • Hemispheric temperature • 3. Global warming and the Atlantic

3. Schematic of Atlantic Ocean Circulation Sinking water at high latitudes Ocean moves heat poleward 1.3*1015 Watts from “Earth's Climate Past and Future”, Ruddiman.

7. Question: The rate of heat (energy) transported by the Atlantic ocean is ~1.3 *1015 Watts. The amount of energy moved poleward by the Atlantic Ocean each year is the equivalent to approximately how many years of total U.S. electricity generation:

8. Observed Atlantic Sea Surface Temperature Temperature (Deg C) (60oW-20oW,6oN-18oN) Tropical North Atlantic

9. Outline: • Basics of the Atlantic Ocean • Multidecadal changes in the Atlantic: impact on climate • African drought • Conditions for tropical storms • Hemispheric temperature • 3. Global warming and the Atlantic

10. Atlantic Ocean Temperature (80oW-0oW,0oN-60oN)

11. Observed change in Sea Surface Temperature (Deg C) 1996-2005 minus 1970-1990 Where did the largest warming take place? Data from Aug-Oct

12. Tree ring records show that AMO-like fluctuations have existed for centuries. Gray et al., 2004, Geophysical Research Letters

13. How can we better understand (and predict) the impact of the North Atlantic ocean on climate? • Diagnostic analyses of observational data • Use computer models of the climate system to better understand how the climate system works (cause and effect) and to predict its future evolution Computer climate model is a “Virtual Earth”, in which we can perform many experiments to better understand the system.

14. In models, the earth’s land, ocean and atmosphere are chopped into 5 million grid cells. Horizontal Grid (Latitude-Longitude) Vertical Grid (Height or Pressure) Climate models use world’s fastest supercomputers … but need computers that are 1000 times faster (at least!).

15. Where is climate modeling done?

16. Where is climate modeling done? ENGLAND JAPAN CANADA GERMANY USA Princeton, NJ New York, NY Boulder, Colorado AUSTRALIA

17. Observed Precipitation (mm/month) 100 mm/month is about 50 inches per year Data from Univ. of East Anglia, Climatic Research Unit (CRU) January Sahel Seasonal migration of Intertropical Convergence Zone (ITCZ) July

18. 1950-2000 trends in observed and simulated precipitation (JAS) Simulated Observed (Atmosphere model forced with observed SSTs 1950-2000)

19. Simulated rainfall changes Modeled AMO Index Observed AMO Index Observed rainfall changes

20. Let’s do a poll question! The rainy season in the Sahel region of Africa is:

21. Simulated Summer Rainfall Changes Associated with Warm North Atlantic Blue means more rainfall when the North Atlantic is warm Units: cm/day

22. Simulated multidecadal JJAS surface air temperature difference (K) (1931-1960) – (1961-1990)

23. Question: The Sahel region of Africa is particularly prone to drought because:

24. NOAA National Hurricane Center 2005 Outlook

25. Reduction in Wind Shear when North Atlantic Warms relative to South Atlantic Observations Model (GFDL CM2.1) Zhang and Delworth, 2006 Red means less shear, and therefore more favorable conditions for hurricanes. CONCLUSION: Models demonstrate that a warming North Atlantic (relative to the South Atlantic) CAUSES atmospheric circulation changes that are favorable for tropical activity.

26. Outline: • Basics of the Atlantic Ocean • Multidecadal changes in the Atlantic: impact on climate • African drought • Conditions for tropical storms • Hemispheric temperature • 3. Global warming and the Atlantic

28. Let’s do a poll question! If all emissions of carbon dioxide were stopped tomorrow, how long would the ocean continue to warm?

29. What the Climate Models Predict: You are here (now)

30. Observed and Modeled Tropical North Atlantic SST Modeled (GFDL CM2.1) Observed Key uncertainty: Role of aerosols In late 20th century Steady or slightly cooling temps Rapid Warming

31. Looking at 21st Century SimulationsProjected Atlantic SST Change (relative to 1991-2004 mean) Areal average 70oW-0oW 0oN-60oN Results from GFDL CM2.1 Global Climate Model (SRES A1B) Observed Trend from 1950-2004

32. Summary/Discussion • - Atlantic Ocean plays a crucial role in climate through • transporting large amounts of heat from the Tropics to • higher latitudes. • - Multidecadal fluctuations in ocean circulation have • strong influence on climate, including African and Indian • monsoon rainfall, Atlantic hurricane activity, and North • American temperature. • - Increasing greenhouse gases are significantly warming • the Atlantic, and will continue to do so in the future.

33. National Science Teachers Association Gerry Wheeler, Executive Director Frank Owens, Associate Executive Director Conferences and Programs Al Byers, Assistant Executive Director e-Learning NSTA Web Seminars Flavio Mendez, Program Manager Jeff Layman, Technical Coordinator Judith Lopes, Administrative Assistant Susan Hurstcalderone, Volunteer Chat Moderator LIVE INTERACTIVE LEARNING @ YOUR DESKTOP