1. Hurricane Sandy and Climate Change AOSS 480 - 4/20/2015 Bukowski, Frey, Loeffler, Slevin http://eoimages.gsfc.nasa.gov/images/imagerecords/79000/79553/sandy_goe_2012302_1745_lrg.jpg

2. Presentation Outline 1)Analysis of Hurricane Sandy 2)Attribution to Climate Change 3)Discussion of Forecast Models 4)Conclusions From hurricanewarningcenter.com

3. Analysis of Hurricane Sandy

4. Tropical wave left Western Africa Timeline 10/11 2012 10/22 10/2410/25 10/29 Wave enters Caribbean Sea and begins to strengthen 10/18 ●Storm classified as Tropical Depression 18, south of Jamaica ●6 hours later: Named Tropical Storm Sandy Classified Hurricane Sandy with 85+ mph winds, passed over Jamaica Classified Major Hurricane Sandy with 115+ mph winds, made landfall in Cuba Lost, then regained hurricane status after passing through the Bahamas and winds had doubled in radius ●Began to turn north, reached secondary peak strength of 100 mph ●Reclassified as extratropical ●Center made landfall in New Jersey with 80 mph winds and 945 mb central pressure Center became ill defined over Ohio as storm rapidly weakened 10/31 10/27

5. H

6. Records and Significance

7. Size ●Diameter of Tropical Storm force winds extended 1000 miles near time of landfall in New Jersey ●Due in part to partial transition to extratropical system, then back to tropical, then finally fully extratropical ●Largest Atlantic hurricane since records began in 1988 Winds/Pressure ●Peak winds of 115 mph at landfall in Cuba (Category 3 strength) ●Secondary peak of 100 mph of eastern US coast ●Winds of 80 mph at landfall in New Jersey ●Low pressure of 945 mb made it the strongest storm to strike north of Cape Hatteras, NC since the 1938 New England Hurricane Rainfall ●Maximum of 28 inches of rain in Jamaica ●Maximum US rainfall of 13 inches in Maryland Storm Surge ●Impacted water levels from Florida to Maine ●Battery Park (tip of Manhattan) saw 14 foot storm tide - 4 feet higher than previous record from 1992 NWS Advanced Hydrologic Prediction Service

9. Impacts Damage estimated at $50 billion - second only to Hurricane Katrina (2005) 72 direct deaths in US, most due to storm surge Deadliest non-southern hurricane since Agnes (1972) 87 indirect deaths - most due to extended power outages 650,000 homes damaged, 8.5 million people lost power Nearly 20,000 flights canceled http://blogs.agu.org/geospace/files/2014/10/Hurricane_Sandy_New_Jersey_Pier_cropped.jpg http://darkroom.baltimoresun.com/wp- content/uploads/2012/10/REU-STORM- SANDYHURRICAN-12.jpg

10. Attribution to Climate Change

11. Extreme Events Non-extreme events can have extreme impacts Occurring simultaneously with other events Location Not all extreme events lead to serious impacts Sandy as an extreme event http://en.wikipedia.org/wiki/Hurricane_Sandy

12. Climate Attribution Analyze observations and climate relationships while experimenting with climate models for comparison Separate signal from noise Attribution important for decision making Fingerprinting Joint attribution Event attribution Santer et al., Nature (1996)

13. Extreme Event Attribution Extreme events are rare Probabilistic event attribution Find fraction of risk only from anthropogenic drivers Event could happen naturally by chance Event recurrence interval How often an event will occur http://www.southwestclimatechange.org

14. Tropical Cyclones Tropical cyclone (TC): rotating, organized system of clouds and thunderstorms that originates over tropical waters Historical data on TCs is unreliable, and link to climate change uncertain Low confidence in observed increase in TC activity Incomplete understanding of physical mechanisms linking TCs to climate change http://sos.noaa.gov/Education/forecast.html

15. Tropical Cyclone Attribution Increase in TC damage Difficult to attribute due to quality of data and internal variability Signal has not emerged No individual TC can be directly attributed to climate change Weather and climate are not independent Vecchi and Knutson (2007)

16. Tropical Cyclone Predictions Increase in average intensity Decrease in overall frequency Increase in frequency of most intense storms, max wind speeds, and precipitation rates Storm track will shift Sea level rise will increase storm surge Population increase in risk-prone areas Bender et al. 2010

17. Sandy Impact Attribution 1950 Impact Probability Occurrence: 435 years - New Jersey 2330 years - NYC 2013 Impact Probability Occurrence: 295 years - New Jersey 1570 years - NYC Sea level rise will increase risks Bulletin of the American Meteorological Society - 2013

18. Attribution Summary Not all extreme events have extreme effects, and non- extreme events can have severe impacts Extreme events are a natural part of climate variability Climate change is a contributor to extreme events, not a cause Climate change alters frequency, intensity, extent, and duration of extreme events Use Probabilistic Event Attribution Framework and Event Recurrence Intervals to quantify anthropogenic forcing Treat climate and weather together, not separately

19. Discussion of Forecast Models

20. Model Problems Not this model problem...

21. Model Problems...this model problem

22. Discussion of Forecast Models In this section we will discuss the differences in the GFS and the ECMWF models, as well as each of their performances during Hurricane Sandy

23. GFS and ECMWF Both are global domain, spectral models Different microphysical schemes GFS - Simple Cloud Scheme ECMWF - Predicted cloud liquid and ice, rain, snow, and cloud fraction scheme

24. Model Performances

25. Model Performance The ECMWF forecasted a turn to the coast two days before the GFS Why was it able to do forecast so much better?

26. Computing Power At the time of Hurricane Sandy, the ECMWF had superior computing power. Process a higher resolution, resolve smaller phenomenon

27. GFS Improvements Recently in January 2015, the GFS upgraded their system as a part of the Disaster Relief Appropriations Act of 2013. Authorized $60 billion in disaster relief $300 million to NWS Of $300 million, $23.7 million was portioned to improve the American models

28. GFS Improvements The GFS now has superior computing power for the first time since the early 90s. GFS - 2,600 teraflops ECMWF - 2,217 teraflops

29. Is the GFS Problem Solved? Shortly after the update, the GFS performed better than the ECMWF in forecasting the New England blizzard event. Due to a small sample size and a wide variety of extreme weather events, it is far too early to say that the GFS is now “better” than the ECMWF.

30. ECMWF Website (Before Blizzard)

31. ECMWF Website (After Blizzard)

32. Why choose GFS? Easy to judge after the event One model vs another, not overwhelming

33. Conclusions ● Hurricane Sandy was an extreme event ● Climate change does not cause extreme events but contributes to them ● As sea level rises, so does the chance for Sandy-like damage ● GFS model failed to predict Sandy’s storm track ● Updates to GFS may not be obvious in the near future

34. Questions?

35. References http://www.nhc.noaa.gov/data/tcr/AL182012_Sandy.pdf http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2283 http://www.iowastatedaily.com/news/article_e9c808dc-22df-11e2-bed4-0019bb2963f4.html http://www.usatoday.com/story/todayinthesky/2012/11/01/airline-cancellation-tally/1673823/ http://www.wmo.int/pages/prog/arep/press_releases/2006/pdf/iwtc_summary.pdf http://earthzine.org/2011/04/17/changing-the-media-discussion-on-climate-and-extreme-weather/ http://www.ametsoc.org/2012extremeeventsclimate.pdf Vecchi, G., & Knutson, T. (2007). On Estimates Of Historical North Atlantic Tropical Cyclone Activity. Journal of Climate, 21, 1-1. Knutson, T., et al. (2010). Tropical Cyclones And Climate Change. Nature Geoscience, 3, 157-163. Knutson, T., et al. (2013). Dynamical Downscaling Projections of Twenty-First-Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-Based Scenarios. Journal of Climate, 26, 6591-6617. Larow, T., L. Stefanova, and C. Seitz, (2014). Dynamical Simulations of North Atlantic Tropical Cyclone Activity Using Observed Low- Frequency SST Oscillation Imposed on CMIP5 Model RCP4.5 SST Projections. Journal of Climate, 27, 8055-8069. Hegerl, G., Von Storch, H., Hasselmann, K., Santer, B., Cubasch, U., & Jones, P. (1996). Detecting Greenhouse-Gas-Induced Climate Change With An Optimal Fingerprint Method. Journal of Climate, 2281-2306. Santer, B., et al. (1996). A search for human influences on the thermal structure of the atmosphere. Nature, 382, 39-46. Rosenzweig, C., et al. (2008). Attributing Physical And Biological Impacts To Anthropogenic Climate Change. Nature, 353-357. Bindoff, N.L. et al., (2013) Detection and Attribution of Climate Change from Global to Regional: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Nicholls, N., et al. (2013) Changes in climate extremes and their impacts on the natural physical environment: IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Bender, M., Knutson, T., Tuleya, R., Sirutis, J., Vecchi, G., Garner, S., & Held, I. (2010). Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes. Science, 327, 454-458.