5B.5
The misuse and misinterpretation of the ACE and PDI indices for hurricane energetics
Angela M. Fritz, Georgia Institute of Technology, Atlanta, GA; and J. I. Belanger, J. A. Curry, and G. J. Holland
The Accumulated Cyclone Energy (ACE) index and the Power Dissipation (PDI) Index are widely used as
metrics to quantify seasonal hurricane activity both in the Atlantic basin and worldwide.
It can be shown that both of these indices are based on inaccurate assumptions that lead
to a misuse and misinterpretation of the resulting index. Towards advancing the indices of
hurricane energetics that are associated with potential damage, we develop a new methodology for calculating
an integrated kinetic
energy (IKE) climatology. A simple, observation and dynamical – based radial wind
speed model is used with the Extended Best Track dataset to calculate IKE for North
Atlantic Hurricanes from 1988 to 2008. The method is evaluated against previous
methods of tropical cyclone intensity analysis, and the results are compared to traditionally misinterpreted
indices in terms of characterizing storm energetics and relating it to storm surge. It is
shown that the traditional indices are inaccurate measurements of hurricane energetics,
and the assumptions that they are based on are not valid.
Session 5B, Topics in Applied Climatology II
Tuesday, 19 January 2010, 1:30 PM-3:00 PM, B212
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