HR: 15:55h
AN: OS52E-07    [PDF]
TI: Sediment Dispersal Mechanisms within the Adriatic Sea: Insights from the EuroStrataform Program
AU: * Harris, C K
EM: ckharris@vims.edu
AF: Virginia Institute of Marine Science, P.O. Box 1346, Route 1208 Greate Road, Gloucester Point, VA 23062 United States
AU: Sherwood, C R
AF: US Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543
AU: Signell, R P
AF: NATO/SACLANT Undersea Research Centre, Viale San Bartolomeo 400, La Spezia, Italy
AB: EuroSTRATAFORM aims to relate sediment delivery and water column transport to seabed morphology. Towards this end, data from near-bottom tripods, current meter moorings, and sediment cores were obtained between November, 2002 and May, 2003. Oceanographic conditions and sediment suspension have been monitored near the dominant source of freshwater and sediment to the Adriatic, the Po River, since a major flood during the Fall of 2000. Modeling investigations, such as the one described here, quantify sediment dispersal within the Adriatic, and thereby encompass spatial and temporal scales that can not be addressed by observational efforts alone. Sediment distributions point to the Western Adriatic Coastal Current (WACC) as a dominant dispersal mechanism, because depocenters hug the coastline and appear down-current from sediment sources. Besides transport by oceanographic currents, however, sedimentation is influenced by wave-induced resuspension. It is unclear the degree to which along-coast gradients in the WACC or wave energy account for changes in sediment accumulation rates, textural properties, and the cross-shelf geometry of sediment deposits. To address this, we apply a three-dimensional hydrodynamic model of the Adriatic that includes fluvial delivery, transport, resuspension, and deposition of sediment. Calculations were driven by spatially- and temporally-varying wind fields for the Fall / Winter of 2002 / 2003 and realistic Po and Apennine river discharges. Waves were hindcast with the SWAN model. Dispersion of both resuspended and river-derived sediment was estimated for periods that contained intense Bora and Sirocco winds. Predicted sedimentation and dispersal rates are sensitive to forcing winds, buoyancy, and wave patterns. Sirocco winds weaken the WACC, and because they tend to concentrate over the Eastern Adriatic, often fail to create especially energetic waves in the Western Adriatic. Bora wind conditions, on the other hand, intensify the WACC and can build high wave energies over the northwestern Adriatic. Higher sediment flux was therefore predicted during Bora conditions than during Sirocco conditions.
DE: 4219 Continental shelf processes
DE: 4243 Marginal and semienclosed seas
DE: 4255 Numerical modeling
DE: 4558 Sediment transport
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting