Impact of mesoscale eddies on the Gulf Stream and shelf ecosystem in the southeastern United States

Ruoying He (North Carolina State University, United States)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: OSTST Opening Plenary Session

Presentation type: Type Keynote/invited

Impacts of mesoscale eddies on the Gulf Stream (GS) mean flow and its adjacent shelf ecosystem variability off the coast of the southeastern United States are studied using hydrographic measurements, satellite observed ocean height and temperature data, as well as model simulations. Observations have shown that the seaward deflection of the GS by the Charleston Bump has a bimodal (either weakly or strongly deflected) character and that the GS meander field downstream of the bump differs significantly between the two states. In a strongly deflected state, the GS tums sharply eastward at the bump and flows seaward far enough to have its surface temperature front offshore of the 600-m isobaths, and can remain so along the continental slope downstream of the bump for several months. Our analyses reveal that topographically induced instability and reduced upstream transport trigger such a strong deflection. Open-ocean cyclonic eddies act in concert to help maintain this state by a vorticity injection mechanism. In the meantime, the compensating flows at the bottom transport nutrient rich deep-water onshore, supporting larger than usual primary productivity on the shelf.
 

Keynote/invited presentation show times:

RoomStart DateEnd Date
Ballroom Tue, Oct 28 2014,11:40 Tue, Oct 28 2014,12:00
Ruoying He
North Carolina State University
United States
rhe@ncsu.edu