Cross-slope transport of dense water from the East Greenland shelf and the role of barrier winds

The seas around Greenland constitute an important and atmospherically sensitive part of the ocean's thermohaline circulation. A recently identified feature, the East Greenland Spill Jet, is characterized by dense water spilling off Greenland's continental shelf south of Denmark Strait. The spilled water forms a strong gravity current along the continental slope with a southward transport comparable to that of the Denmark Strait Overflow in its upper reaches. Hence the Spill Jet represents a potentially significant contribution to the Atlantic meridional overturning circulation. However, the controlling factors for this spilling process are still poorly understood. Using oceanic data from a mooring deployed on the outer Greenland shelf from September 2007 to October 2008, together with high-resolution meteorological reanalysis fields from the ERA-interim product, the nature and forcing of the East Greenland Spill Jet is investigated. The mooring data reveal that spilling events are frequent and strong, transporting dense water offshore. Different forcing mechanisms are explored, including the role of the strong northerly barrier winds that arise during autumn and winter as a result of synoptic cyclones impinging on the steep, high coastline of Greenland. Both local and non-local wind impacts are considered.