Modelling deep seasonal temperature changes in the Labrador Sea

Abstract

An eddy-admitting model of the North Atlantic is applied to study the seasonal variations of temperature at 1000 m in the Labrador Sea. The model successfully reproduces the seasonal cycle of the near-bottom temperature observed from a long-term mooring deployed on the 1000 m isobath on the upper continental slope off Labrador. It also provides an estimate of the spatial distribution of the seasonal temperature variation in the whole Labrador Sea that can be interpreted in terms of the roles played by surface cooling, deep convection, lateral mixing and advection. The model results suggest that mixing along the steeply sloped isopycnal surfaces plays an important role in communicating the cold water formed by surface cooling to deep layers over the Labrador Slope in later winter. Upstream conditions are also communicated to the mooring site along the Slope through advection by the prevailing cyclonic circulation. In particular, the advection of warm water off Greenland contributes to the gradual warming from spring to winter at the mooring site. Copyright 2006 by the American Geophysical Union.