Hurricane Sandy and Climate Change AOSS 480 - 4/20/2015 Bukowski, Frey, Loeffler, Slevin .

Hurricane Sandyand Climate Change

AOSS 480 - 4/20/2015Bukowski, Frey, Loeffler, Slevin

http://eoimages.gsfc.nasa.gov/images/imagerecords/79000/79553/sandy_goe_2012302_1745_lrg.jpg

Presentation Outline1)Analysis of

Hurricane Sandy2)Attribution to

Climate Change3)Discussion of

Forecast Models4)Conclusions

From hurricanewarningcenter.com

Analysis ofHurricane Sandy

Tropical wave left Western Africa

Timeline

10/11

2012

10/22

10/24 10/25

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

H

Records and Significance

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

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.jpghttp://darkroom.baltimoresun.com/wp-content/uploads/2012/10/REU-STORM-SANDYHURRICAN-12.jpg

Attribution toClimate Change

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

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)

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

occurhttp://www.southwestclimatechange.org

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

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)

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

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

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

Discussion ofForecast Models

Model Problems

Not this model problem...

Model Problems

...this model problem

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

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

Model Performances

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?

Computing Power

• At the time of Hurricane Sandy, the ECMWF had superior computing power.

• Process a higher resolution, resolve smaller phenomenon

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

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

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.

ECMWF Website (Before Blizzard)

ECMWF Website (After Blizzard)

Why choose GFS?

• Easy to judge after the event

• One model vs another, not overwhelming

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

Questions?

Referenceshttp://www.nhc.noaa.gov/data/tcr/AL182012_Sandy.pdfhttp://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2283http://www.iowastatedaily.com/news/article_e9c808dc-22df-11e2-bed4-0019bb2963f4.htmlhttp://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.pdfhttp://earthzine.org/2011/04/17/changing-the-media-discussion-on-climate-and-extreme-weather/http://www.ametsoc.org/2012extremeeventsclimate.pdfVecchi, 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.