Design and Implementation of an Ocean Observing System: WAVCIS (Wave-Current-Surge Information System) and Its Application to the Louisiana Coast

• Main Author: Zhang, Xiongping
• Other Authors: Shih-Ang (S.A.) Hsu
• Format: Others
• Language: en
• Published: LSU 2003
• Subjects: Geography & Anthropology
• Online Access: http://etd.lsu.edu/docs/available/etd-0708103-012004/

WAVCIS (Wave-Current-Surge Information System for Coastal Louisiana) was designed to measure meteorological and hydrodynamic phenomena along the Louisiana coast. The information measured includes waves, currents, water depth, surge, turbidity, salinity and meteorological conditions. WAVCIS collects data and transfers it back to the data processing laboratory at LSU through wireless communication. The data undergo post-processing and archiving. Users can access the real-time or archived information through the World Wide Web. This dissertation utilized the information provided by WAVCIS stations and NDBC buoys during Hurricane Lili and Tropical Storm to examine temporal and spatial variations of storm induced meteorological and oceanographic dynamics. The results show that waves during Hurricane Lili ranged from 1.8 meters in Terrebonne Bay, 6.2 meters offshore at a depth of 20 meters and 12 meters in Central Gulf of Mexico. The track of Hurricane Lili passed over CSI 3 where the peak in significant wave height reached 2.7 meters. The maximum current speeds near sea surface and near bottom generated by Hurricane Lili were 1.8 m/s and 1.1 m/s respectively. During the peak of the storm the water column was dominated by a northwest current. Currents were initially impacted by the storms when they encountered the continental shelf. Within approximately twice the radius of maximum wind (Rw) during Hurricane Lili, the current measured by an ADCP (Acoustic Doppler Current Profiler) exhibited an almost perfect logarithmic profile extending to near the sea surface from the bottom. The range of the estimated shear velocity during the passage of Hurricane Lili was 5-12.5 cm/s. Storm wave energy dumping occurred along the muddy shelf in western Louisiana. Waves generated by Hurricane Lili and Tropical Storm Isidore showed considerable difference in both time and space domains. Wave spectra for Tropical Storm Isidore showed distinct peaks for both swell and wind-driven waves. The wave spectra for Hurricane Lili demonstrated complicated multiple peaks throughout the entire frequency domain. Swells with longer periods tended to survive longer in the space domain and shorter in the time domain. Hurricane Lili generated 1.4 meters of storm surge at CSI 3. The surges appeared lower than modeled estimates.