Evolution of bedforms on the inner-shelf

Download
Author
Dixon, Damon Beecher
Date
2000-09Advisor
Thornton, Edward B.
Stanton, Timothy P.
Metadata
Show full item recordAbstract
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 on the bed at the Monterey Bay Inner Shelf Observatory in thirteen-meter depth water. The bed consists of fine sand (mean grain size 0. 12 mm). Low to moderate narrow-band swell waves occurred during the observation period. Ripple geometry consisted of orbital and suborbital vortex wave ripples, and relic ripples left after larger wave events. The bedforms generally changed size and shape when the grain roughness Shields parameter exceeded a critical value of 0.04. Ripple migration was offshore at rates of 2-10 cm/day during active sediment transport events. Skewness of velocities (low and high passed) were calculated to explain offshore ripple migration, but showed no preferred direction. Mean currents were weak. Significant positive (offshore) correlation was obtained between the short-wave envelope and infragravity waves indicating wave-group forced bound long waves (surf beat) combined with stirring by the short waves might explain the offshore sediment transport and ripple migration
Collections
Related items
Showing items related by title, author, creator and subject.
-
Estimating the Value of Offshore Wind Along the United States’ Eastern Coast [video]
Mills, Andres (Naval Postgraduate School, Monterey, California, 2018-08-10);Offshore wind power development in the United States is challenged, in part, by an unclear understanding of the value that offshore wind provides within an overall electricity portfolio. We develop a rigorous method to ... -
Oceanic Variability Off the Central California Coast
Breaker, Laurence C.; Mooers, Christopher N.K. (1986);Mesoscale variability off the Central California coast is strongly influenced by coastal upwelling and related processes. Off Point Sur, there is significant space-time variability in oceanic properties over periods of ... -
The impact of synoptic-scale flow on sea breeze front propagation and intensity at Eglin Air Force Base
Weaver, James C. (Monterey California. Naval Postgraduate School, 2006-03);This study investigates the impact of the synoptic-scale flow on the propagation and intensity of the sea breeze front at Eglin Air Force Base. The 925 mb wind direction and speed from the 12 UTC Tallahassee sounding was ...