Hurricane Bonnie Wind Flow Characterisitcs

Whether convective influences result in localized areas of increased wind speeds and different turbulent structure than expected in a normal high wind situation has been debated for years. The question has been especially active concerning landfalling hurricanes. Given a lack of high-resolution wind speed data from within hurricanes necessary to resolve the debated questions, a field experiment was designed and conducted by Texas Tech University to acquire the necessary data. The Wind Engineering Mobile Instrumented Tower Experiment (WEMITE), the first successful field experiment to place a reinforced, selfpowered, instrumented tower directly in the path of several hurricanes, successfully gathered high-resolution wind speed data from within Hurricane Bonnie as it made landfall near Cape Fear, North Carolina, on 26 August 1998, at 5:00 PM. These data are used to inspect the variations in turbulent characteristics of the wind during the passage of the storm. Specifically, turbulence intensities, integral scales, gust factors, and spectrograms are evaluated with respect to the surrounding meteorological events, such as the passage of rainbands. Comparisons are drawn between turbulence intensity and integral scale values present in Hurricane Bonnie, and those employed in the determination of the gust effect factor in ASCE 7-98. Wavelet analysis was also used to examine the incoherent model assumption employed in wind engineering.