HR: 16:00h
AN: OS24A-01    [Abstracts]
TI: The Bed State Storm Cycle
AU: * Hay, A E
EM: alex.hay@dal.ca
AF: Dalhousie University, Department of Oceanography, Halifax, NS B3H 4J1 Canada
AB: Results are presented from 70+ days of nearly continuous {\it in situ} acoustic imagery of the nearshore sandy seabed in about 3-m mean water depth. Five principal bed states were observed: irregular ripples, cross ripples, linear transition ripples, lunate megaripples, and flat bed. The linear transition and flat bed states were the most frequent, together accounting for 68% of the total time. Bed state occurrence was a strong function of incident wave energy, each bed state occurring within a relatively narrow range of incident wave energies. The bed response during the 12 major storm events spanned by the record was characterized by a repeatable bed state cycle, involving 4 of the 5 principal states (lunate megaripples did not appear repeatably, and thus may be a special case), and with no obvious dependence on prior bed state, or on 3rd-moment measures of wave non-linearity.
DE: 4546 Nearshore processes
DE: 4558 Sediment transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting