Ground-Level Turbulence Characteristics of Hurricane Wind Measured from Mobile Towers

Surface-level turbulence in the Hurricane Boundary Layer is an important factor in the determination of wind load characteristics for coastal structures. While the necessary data has been collected from fixed stations, very little of it has been collected during an eyewall passage and/or in suburban terrain. Recent field research by the Florida Coastal Monitoring Program using portable mobile towers has enabled us to collect and to analyze the data that could not be obtained previously. This paper analyzes high fidelity wind velocity data collected during Hurricane Ike (2008) to better understand the effect of the terrain conditions in hurricane wind turbulence. Two 10-m instrumented towers were co-located in close proximity to compare suburban and open condition. Their turbulence intensities and power spectra are compared for. In order to deal with the non-stationarity of the data, empirical mode decomposition is employed to de-trend the signal.