HR: 0800h
AN: OS11A-0483    [Abstracts]
TI: Shelf-Slope Exchange in the Mid-Atlantic Bight
AU: * Goodman, P J
EM: paulg@imcs.rutgers.edu
AF: Rutgers University, 71 Dudley Rd, New Brunswick, NJ 08901 United States
AU: Wilkin, J
EM: wilkin@imcs.rutgers.edu
AF: Rutgers University, 71 Dudley Rd, New Brunswick, NJ 08901 United States
AB: A high resolution model (ROMS, the Regional Ocean Modeling System) of U.S. East Coast circulation from Newfoundland to Cuba is used to explore features of alongshelf freshwater transport, residence time, and shelf-sea/deep-ocean exchange. The focus of the analysis is the Mid-Atlantic Bight (MAB) shelf-slope system which, like continental shelves throughout the world, contributes to the oceanic budgets of heat, salt, and fresh water. In addition, the "continental shelf pump" transfers carbon from the atmosphere to the deep ocean through fluxes of dissolved organic carbon and particulate organic carbon off the shelves. Solar radiation, evaporation, rainfall, riverine input, gas exchange with the atmosphere, and biological production all modify the character of shelf waters. In the MAB, the shelf-slope front separates shallow coastal waters from slope waters and the Gulf Stream, extending residence times on the shelf and maintaining coastal salinities at significantly lower levels than those offshore. The southwestward coastal mean flow exchanges weakly with slope waters along most of the MAB, with the strongest offshore flow occurring at Cape Hatteras where much of the flow is entrained into the Gulf Stream front. The shelf circulation is influenced by input from the Hudson and Delaware Rivers and Chesapeake Bay. Along the shelf break, exchange is modulated by warm-core rings from the Gulf Stream and variability of the shelf-break front. Key features of the seasonal circulation such as the MAB "Cold Pool" are captured by the simulation. Measurements suggest that DOC in shelf and shallow slope waters of the MAB include both old marine carbon and a young terrestrial-riverine-estuarine component, and these carbon cycling processes are being studied with a companion primary production, nitogen and carbon cycle model directly coupled to ROMS. Results showing salinity, idealized dye and Lagrangian float tracking results from a ROMS simulation of the MAB shelf circulation are presented. Shelf and slope water freshwater budgets are quantified, including regional variability in onshore/offshore exchange rates, and trhese are compared to observational estimates.
DE: 4546 Nearshore processes
DE: 4558 Sediment transport
DE: 4560 Surface waves and tides (1255)
DE: 3020 Littoral processes
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting