Weifeng Gordon Zhang
Waters on the Mid-Atlantic Bight continental shelf are distinctively different from the waters offshore. The water exchange across the shelf edge takes different forms. In this talk, I will show a direct intrusion of Gulf Stream warm-core ring water onto the shelf representing a previously unknown exchange process at the shelf edge. Impingement of warm-core rings at the shelf edge generates along-isobath intrusions of the ring water that grow like Pinocchio’s nose, extending hundreds of kilometers to the southwest. Analysis of the satellite and Ocean Observatory Initiative Pioneer Array data and numerical simulations reveals that the intrusion results from topographically induced vorticity variation of the ring water. This disproves the common notion that the intrusion is a result of the surface entrainment of the ring water by the shelfbreak frontal jet. This intrusion of the Gulf Stream ring water has important biogeochemical implications. It could facilitate migration of marine species across the shelf edge barrier and transport low-nutrient surface Gulf Stream ring water to the otherwise productive shelf edge region.