The history of the Labrador Sea Water: Production, spreading, transformation and loss

Abstract

In winter, cold Arctic outbreaks from Labrador result in intense air-sea heat exchanges transferring large quantities of heat from the ocean to the atmosphere and intermittently exciting convective mixing known to form the most prominent water mass of the subpolar North Atlantic - the Labrador Sea Water (LSW). The outline of this chapter is as follows. First we provide an overview of the Labrador Sea circulation and water masses, and introduce the Labrador Sea Water (LSW) and the important role it plays in the North Atlantic circulation and budgets of freshwater and heat. After describing the data set used in this study we summarize the variations in the LSW properties over time and across the subpolar North Atlantic. We introduce the technique of volumetric analysis to identify and study different classes of LSW, and use the results to describe the formation and decline of two recent classes. Finally we trace the spreading of those classes across the subpolar North Atlantic, showing how their distinguishing features can be consistently traced to the northern limits of the eastern basin despite very great modification of properties en route. © 2008 Springer Netherlands.