HR: 08:30h
AN: OS11D-03    [Abstracts]
TI: Interactions Between Storms And Dense Water Cascading In The Gulf Of Lion, NW Mediterranean
AU: * Durrieu de Madron, X
EM: demadron@univ-perp.fr
AF: CEFREM CNRS-University of Perpignan, 52 avenue Paul Alduy, Perpignan, 66860 France
AB: The Gulf of Lions is a river-dominated shelf of the northwestern Mediterranean that represents an interesting environment to explore variability of seabed erosional and depositional fluxes. Sediment dynamics is very active in fall and winter when rivers are in flood and southeastern storms impinge the coast. These occasional and brief events inject large amounts of fine sediment on the inner-shelf, which are eventually advected on the outer shelf by a complex shelf circulation. Currents are mainly driven by the continental winds, and usually transport suspended sediment cyclonically along the coast. In late winter and early spring, cascading of cold, dense water reinforces the transport of suspended sediment across the western part of the shelf and towards the slope. From a ten-year time-series of current and flux measurements on the slope, it appears that this mechanism controls the intensity of the export of particulate matter to the continental slope though with a strong internannual variability. Further information on this density underflow was recently gathered and permitted to elucidate its impact on sediment dynamics. A comprehensive field experiment was performed during winter 2004 in the framework of the Eurostrataform program. It comprised several hydrological and ADCP surveys, a monitoring of the storms' impact on the sediment dynamics on the inner shelf, as well as of current, hydrology and particulate fluxes in several canyons that dissect the Gulf of Lions shelf. The data sets offer the opportunity to evidence the downward propagation in the bottom boundary layer of cold and turbid plumes in the canyons, especially those at the southwestern end of the Gulf. It also allows to examine the interactions between the resuspension of fine sediment by two storms that occur during that period and the transport of suspended sediment by dense water cascading.
DE: 4211 Benthic boundary layers
DE: 4219 Continental shelf processes
DE: 4558 Sediment transport
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting