Seafloor ripples created by waves from hurricane Ivan on the West Florida Shelf
Bowers, Colleen Marie.
MetadataShow full item record
Recent studies have shown that the presence of sand ripples on the seabed improves sonar detection of buried mines at sub-critical angles. Sidescan sonar data of ripples off on the west Florida shelf were collected as part of ONR's Ripples Departmental Research Initiative (DRI) September 26-29th and November 7-9th, 2004. Hurricane Ivan, the strongest storm of the 2004 hurricane season, passed over the experiment site a week before the first data collection. This study focuses on the ripples created by Ivan. Average relict ripple wavelengths left after the storm were found to increase with water depth (50 cm, 62 cm, and 83 cm in 20, 30, and 50 meter water depths) despite the fact that orbital diameter decreases with water depth. Ripple prediction requires information about surface gravity waves and sediment grain size. The most reliable offshore wave field available was created with Wavewatch III by Naval Postgraduate School scientists. These waves were inputted into Delft3D WAVE, incorporating the nearshore wave model SWAN to predict waves at the locations where ripples were measured. Orbital motions at the seabed and grain size were inputted into a time-dependent ripple model with varying dissipation parameters to estimate sand ripples created by Hurricane Ivan. Ripple wavelength was found to be more strongly dependent on grain size than wave dissipation.
Showing items related by title, author, creator and subject.
Clifford, William Francis; Erman, Reginald Joseph (Monterey, California. Naval Postgraduate School, 1979-03);Large, fresh-water ice blocks (0.5m X 1.25m X 5m) were towed in Monterey Bay at speeds in range from 0.7 to 1.2 knots, The objectives of the experiments included measurement of gross regression rates of ice surfaces, ...
Weltmer, Micah A. (Monterey, California. Naval Postgraduate School, 2003-03);Observations of the temporal evolution of ripples are analyzed in terms of geometry, migration, crest orientation, and their predicted geometry by models using wave orbital velocities. Two weeks of bedform data were obtained ...
Dixon, Damon Beecher (Monterey, California. Naval Postgraduate School, 2000-09);Observations of the temporal evolution of the wave-formed ripples are analyzed in terms of geometric properties. Three weeks of bedform observations were obtained using underwater video of a sheet of laser light projected ...