Climate Change and the Track and Intensity of Hurricane Sandy

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Tuesday, 4 February 2014: 3:30 PM
Room C102 (The Georgia World Congress Center )
Gary Lackmann, North Carolina State Univ., Raleigh, NC

Hurricane Sandy was associated with historic societal impacts when it made landfall along the New Jersey shore in late October 2012. The event generated vigorous discussions as to whether the severity, or perhaps occurrence, of the event was tied to anthropogenic climate change. Two related questions are (i) whether the frequency of this type of event is altered by anthropogenic climate change, and (ii) if the synoptic pattern accompanying Hurricane Sandy had taken place in 100 years ago (or 100 years in the future), how would the track, intensity, and impacts have differed?

Here, we investigate question (ii) using a simplified approach that is designed to quantify the storm-scale changes attributable to large-scale thermodynamic changes. An ensemble of WRF model simulations, in conjunction with GCM-derived large-scale thermodynamic changes, is used to determine the dynamical changes. One initial hypothesis is that the diabatically driven outflow from Sandy would be lessened in the past, which would reduce the strength of the downstream ridge event, and result in a more easterly track of Sandy. Similarly, we hypothesize that a futuristic version of Sandy would be characterized by stronger condensational heating, even greater diabatic ridging to the north and east, and a more westerly track. However, previous studies document an increase in the strength of the upper westerlies with future warming, which would impart the opposite effect on the storm track. The results of these hypothesis tests will be presented, along with analysis of changes in rainfall, near-surface wind speed, and other impact parameters. The results are not consistent with the first hypothesis: The future simulation produces the most easterly track, but the greatest intensity.