Directional Wave Spectra on the Louisiana-Texas Shelf During Hurricane Andrew

During Hurricane Andrew, the Louisiana-Texas Shelf Physical Oceanography Program (LATEX) had wave gauges (three directional, one non-directional) deployed at four sites along the Louisiana-Texas Shelf. We present the directional wave spectra at two sites and wave kinematics at all sites utilizing the measured pressure and horizontal velocity. The effects of Andrew first became evident on the Louisiana-Texas Shelf in the wave spectra with the arrival of waves of about 16 second period at a site 20 km south of Terrebonne Bay, LA; about 14.5 hours later they arrived off South Padre Island, TX. Both arrival times corresponded to a location for Andrew in the far eastern Gulf at 25.7N, 83.1W. Many of the features of the wave propagation across the Gulf of Mexico seem to be explained using linear wave theory. However, the peak significant wave height exceeded 9 meters at the site near Terrebonne Bay, LA as the storm center passed within 30 km. The spectra were distinctly bimodal during the 8 hour period when the eye was closest to the gauge, with energy in the 0.15 to 0.22 Hz band accounting for 37% of the total energy. Some of the high frequency energy may have been locally generated, but a significant portion was probably a result of nonlinear second-order sum-frequency effects.

Directional Wave Spectra on the Louisiana-Texas Shelf During Hurricane Andrew Academic Article