The East Greenland Spill Jet*

TLDR

Dense water cascading over the East Greenland shelf edge entrains ambient water, forming the spill jet, while the Irminger Sea boundary current system includes additional components with absolute transports. High‑resolution measurements revealed the East Greenland Spill Jet, a narrow, equatorward‑transporting (~2 Sv) current beneath the Irminger Current, with strong vertical mixing, minimal downstream entrainment, and a sharp potential‑vorticity front driven by cyclonic vorticity and tilting.

Abstract

Abstract High-resolution hydrographic and velocity measurements across the East Greenland shelf break south of Denmark Strait have revealed an intense, narrow current banked against the upper continental slope. This is believed to be the result of dense water cascading over the shelf edge and entraining ambient water. The current has been named the East Greenland Spill Jet. It resides beneath the East Greenland/Irminger Current and transports roughly 2 Sverdrups of water equatorward. Strong vertical mixing occurs during the spilling, although the entrainment farther downstream is minimal. A vorticity analysis reveals that the increase in cyclonic relative vorticity within the jet is partly balanced by tilting vorticity, resulting in a sharp front in potential vorticity reminiscent of the Gulf Stream. The other components of the Irminger Sea boundary current system are described, including a presentation of absolute transports.