Shelf-deep ocean exchange at Cape Hatteras from two years of underwater glider observations

Robert E Todd, Woods Hole Oceanographic Institution, Physical Oceanography, Woods Hole, MA, United States
The area around Cape Hatteras, NC is a region of intense exchange between the continental shelf and deep ocean. Convergence of shelf waters from the Middle Atlantic Bight and South Atlantic Bight results in net export of shelf waters, while both the nearby Gulf Stream and variable atmospheric forcing modulate the location and sign of instantaneous flow across the edge of the continental shelf. From April 2017 through April 2019, Spray gliders continuously surveyed along the upper continental slope north of Cape Hatteras as part of the `Processes driving Exchange At Cape Hatteras (PEACH)’ program. Gliders returned more than 100 transects between the northern edge of the Gulf Stream and just south of Norfolk Canyon (a distance of about 140 km), as well as more than 70 transects across the shelfbreak front and outer shelf near Norfolk Canyon. These observations are used to examine the mean and variability of exchange between the shelf and deep ocean through two complete annual cycles.