HR: 15:15h
AN: OS23H-06    [Abstracts]
TI: Cross-shelf transport of freshwater in the New Jersey shelf
AU: * Castelao, R M
EM: castelao@marine.rutgers.edu
AF: Rutgers University, Institute of Marine and Coastal Sciences, 71 Dudley Road, New Brunswick, NJ 08901, United States
AU: Glenn, S
EM: glenn@marine.rutgers.edu
AF: Rutgers University, Institute of Marine and Coastal Sciences, 71 Dudley Road, New Brunswick, NJ 08901, United States
AU: Schofield, O
EM: oscar@marine.rutgers.edu
AF: Rutgers University, Institute of Marine and Coastal Sciences, 71 Dudley Road, New Brunswick, NJ 08901, United States
AU: Chant, R
EM: chant@marine.rutgers.edu
AF: Rutgers University, Institute of Marine and Coastal Sciences, 71 Dudley Road, New Brunswick, NJ 08901, United States
AU: Kohut, J
EM: kohut@marine.rutgers.edu
AF: Rutgers University, Institute of Marine and Coastal Sciences, 71 Dudley Road, New Brunswick, NJ 08901, United States
AB: The New Jersey Shelf Observing System, which includes real-time access to the international constellation of ocean satellites, a nested HF CODAR radar network, cabled moorings and a fleet of Webb Sloccum gliders, is used to investigate the freshwater content over the New Jersey shelf. Repeated hydrographic surveys about 100 km south of the Hudson River mouth were conducted using gliders during spring and summer 2006. Observations reveal a strong seasonal cycle in the surface salinity. Buoyant water is restricted to being close to the coast during spring, but spans the entire shelf width during summer. During late July and August, freshwater lenses with large density anomaly are found up to 100 km from the coast. The cross-shelf transport of the freshwater is inconsistent with a model based on Ekman dynamics [Lentz, 2004], suggesting that other processes are responsible for the rapid cross-shelf transport. Surface velocity maps derived from HF radar, satellite imagery and drifter trajectories revealed the existence of a jet directed offshore and to the south, from near the river mouth toward the study region. This provides a direct pathway for transporting freshwater and any biogeochemical material it contains (including phytoplankton, dissolved organic and non-algal particulate matter) across the shelf. The highest frequency of observation of the freshwater lenses offshore occurs when the jet transport is large, and the river discharge is relatively high. The transport in the jet is correlated with upwelling winds on scales of a few days.
DE: 4219 Continental shelf and slope processes (3002)
DE: 4262 Ocean observing systems
DE: 4528 Fronts and jets
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly