Evolution of North Atlantic Water Masses Inferred from Labrador Sea Salinity Series

Igor Yashayaev,Allyn Clarke

doi:10.5670/oceanog.2008.65

Abstract

The Labrador Sea is the coldest and freshest basin of the North Atlantic. Winter cooling in this sea produces Labrador Sea Water. This intermediate water plays an important role in the exchange of heat, freshwater, and other substances between the atmosphere and the abyssal ocean, affecting the water masses, circulation, and, ultimately, climate of the subpolar North Atlantic basins. The subpolar gyre of the North Atlantic has exhibited large changes in temperature, salinity, and volume over the past six decades, largely in response to changing winter conditions over the Labrador Sea. The signature of these changes can be seen in the lower limb of the Meridional Overturning Circulation down into the North Atlantic tropics.

Highlights

In troduction The subpolar sector of the North Atlantic Ocean is the region where the warm, saline upper-layer waters from the low latitudes meet the cold, less-saline outflows from the high latitudes and interact to mix and exchange their properties
The global ocean conveyor, by transforming poleward flows of warm saline upper waters to deep return flows of cold, less-saline waters, makes a significant contribution to the global distribution of heat, freshwater, and a variety of other substances carried by seawater
Because the net poleward atmospheric moisture flux is largely compensated by the net oceanic freshwater transport, any sustained change in regional salinity would likely reveal an important tendency in the large-scale redistribution of freshwater and sea salt that would provide insight for understanding and predicting possible climate change

Summary

Introduction

In troduction The subpolar sector of the North Atlantic Ocean is the region where the warm, saline upper-layer waters from the low (tropical and subtropical) latitudes meet the cold, less-saline outflows from the high (polar) latitudes and interact to mix and exchange their properties. By the time these waters reach the Labrador Sea to the west or the Greenland Sea and Arctic Ocean to the north, they become dense enough that one more strong winter cooling season will result in deep convectively mixed layers extending to depths of 2 km and greater.

Results

Conclusion