Evolution of Fronts in the Mid-Atlantic Bight: What Exit on the Ocean Highway Off New Jersey?

The New Jersey Shelf Observing System (NJSOS), a regional ocean observatory, is currently deployed in the New York Bight as part of the larger NorthEast Observing System (NEOS). Remote sensing data from an international constellation of satellites and a CODAR-type HF radar surface current array provide continuous synoptic surface maps over the shelf. For 2002 and 2003, full resolution NOAA AVHRR (~1 km) and SeaWiFS (~1.1 km, 4th reprocessing) imagery of the New York Bight region were averaged into time composites from 4 to 90 days. Long-range current maps were similarly averaged to match the scales of the satellite composites. Long-term averages of surface currents in the MAB indicate two transport pathways to the outer shelf. One originates near the mouth of New York Harbor and moves out along the Hudson Canyon. The second, originating upshelf, enters the field from the north and moves slowly toward the south. The flow along the Hudson Canyon is an alternative pathway that is a more direct transport to the shelf/slope region of the MAB. The sea surface temperature over the Hudson Canyon shows similar links to the canyon topography with cold inner shelf water following the 50 m isobath, and warmer water offshore. Similarly there is a lower chlorophyll concentration over the canyon than in the surrounding water. Although the temperature signature in the New York Bight is strongest in the winter, CODAR and surface chlorophyll measurements indicate the Hudson Canyon front occurs year round and can have significant influences on cross-shelf transport of organic material.