Labrador Sea Water
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Labrador Sea Water is an intermediate water mass in the Labrador Sea. It is characterized by cold water, relatively low salinity compared to other intermediate water masses,[1] and high concentrations of both oxygen and anthropogenic tracers.[2] It is formed by convective processes [3] located between Greenland and the northeast coast of the Labrador Peninsula. Deep convection in the Labrador Sea allows colder water to sink forming this water mass, which is a contributor to the upper layer of North Atlantic Deep Water. North Atlantic Deep Water flowing southward is integral to the Atlantic Meridional Overturning Circulation.[4] The Labrador Sea experiences a net heat loss to the atmosphere annually.
Convection in the Labrador Sea is the result of cyclonic circulation of the sea currents and cyclonic atmospheric forcing. At the southern tip of Greenland, water enters the West Greenland Current from the East Greenland Current, continues to flow northwest around Baffin Bay, and then southeast into the Baffin Island Current, continuing in the same direction in the Labrador Current. Sea ice in the winter months inhibits surface flow into Baffin Bay. The Labrador Current and the Western Greenland Current flow in opposite directions, creating a cyclonic eddy. During winter months low pressure dominates in this region,[5] and in years with a positive North Atlantic Oscillation deeper convection is observed.[6]
Spreading
Labrador Sea Water spreads through the North Atlantic Ocean by three routes: northeast directly into Irminger Sea, into the eastern North Atlantic by means of the deep North Atlantic current, and meridionally via the Deep Western Boundary Current.[2] A 2002 study presented data that suggest that the Labrador Sea is not the only formation site for Labrador Sea Water. They observed similar convective processes in Irminger Sea and noted that transit times for Labrador Sea Water into Irminger Sea were unusually fast, suggesting that Irminger Sea as another source.