Sack Lunch Seminar (SLS)

In the Middle Atlantic Bight (MAB), a shelfbreak front separates cool, fresh shelf waters from warmer, saltier slope waters; farther offshore, the Gulf Stream carries even warmer and saltier waters. Analysis of upper ocean thermohaline structure over the shelfbreak and continental rise reveals that interleaving of shelf and slope waters across the shelfbreak is the leading source of cross-shelf horizontal variability within at least 100 km of the shelfbreak and contributes to alongshelf horizontal variability within 50 km of the shelfbreak. Horizontal spatial scales increase from O(10 km) near the shelfbreak to O(30 km) over the continental rise. Entrainment of shelf water by anticyclonic Gulf Stream warm core rings is a leading mechanism of exchange across the shelfbreak front. Recent observations in the MAB and laboratory experiments show that larger volumes of shelf water are carried farther offshore as the relative strength of anticyclones increases. In rare cases, the Gulf Stream itself impinges upon the shelfbreak; in the fall of 2011, such an event brought warm, salty Gulf Stream waters onto the outer continental shelf south of Cape Cod.