Fidelity of the integrated kinetic energy factor as an indicator of storm surge impacts

Abstract

After the devastating hurricane season of 2005, shortcomings with the Saffir–Simpson Hurricane Scale’s (SSHS) ability to characterize a tropical cyclone’s potential to generate storm surge became widely apparent. As a result, several alternative surge indices were proposed to replace the SSHS, including Powell and Reinhold’s integrated kinetic energy (IKE) factor, Kantha’s Hurricane Surge Index (HSI), and Irish and Resio’s Surge Scale (SS). Of the previous, the IKE factor is the only surge index to date that truly captures a tropical cyclone’s integrated intensity, size, and wind field distribution. However, since the IKE factor was proposed in 2007, an accurate assessment of this surge index has not been performed. This study provides the first quantitative evaluation of the IKEs ability to serve as a predictor of a tropical cyclone’s potential surge impacts as compared to other alternative surge indices. Using the tightly coupled Advanced Circulation and Simulating Waves Nearshore models, the surge and wave responses of Hurricane Ike in 2008 and 78 synthetic tropical cyclones were evaluated against the SSHS, IKE, HSI, and SS. Results along the northwestern Gulf of Mexico coastline demonstrate that the HSI performs best in capturing the peak surge response of a tropical cyclone, while the IKE accounting for winds greater than tropical storm intensity (IKETS) provides the most accurate estimate of a tropical cyclone’s regional surge impacts. These results demonstrate that the appropriate selection of a surge index ultimately depends on what information is of interest to be conveyed to the public and/or scientific community.