An estimate of the eddy-induced circulation in the Labrador Sea

• Published in: Geophysical research letters Vol. 27; no. 15; pp. 2277 - 2280
• Main Authors: Khatiwala, Samar, Visbeck, Martin
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.08.2000; American Geophysical Union
• Subjects: Baroclinic instability; Boundaries; Circulation; Earth, ocean, space; Exact sciences and technology; External geophysics; Geophysics; Labrador; Marine; Mathematical models; Outflow; Physics of the oceans; Thermohaline structure and circulation. Turbulence and diffusion; Transporting; Atlantic Ocean; Labrador Sea; North Atlantic; ANW, Labrador Sea; ANE, Atlantic, Labrador Sea Water; Sea of Labrador; Baroclinic instability; Sea circulation; Numerical simulation; Vortex; Ocean convection; Comparative study; Geostrophic current; Ocean atmosphere interaction
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/1999GL011073

Regions of oceanic deep convection such as the Labrador Sea are prone to baroclinic instability. The resulting geostrophic eddies play a crucial role in the post‐convection adjustment process which involves both rearrangement of mass so as to release available potential energy and exchange of heat and salt with the boundaries. In this study it is proposed that the slumping of isopycnals associated with baroclinic instability drives an eddy‐induced “overturning circulation” consisting of a surface intensified flow transporting low salinity water from the boundary currents into the interior; sinking motion in the interior; and an “outflow” at depth transporting newly ventilated Labrador Sea Water towards the boundaries. Typical eddy‐induced velocities estimated from hydrographic data are roughly 0.5 cm/s for the surface inflow, 1 m/day for the vertical motion, and 0.1 cm/s for the deeper outflow, in close agreement with those calculated in a numerical model.