Two Sources of Deep Decadal Variability in the Central Labrador Sea Open‐Ocean Convection Region

Abstract

AbstractThe ventilation of the central Labrador Sea is important for the uptake of ocean tracers and carbon. Using historical ocean observations, we construct a simple multiple linear regression model that successfully reconstructs the decadal variability of the upper ∼2,000 m of the central Labrador Sea water properties based on observed indices that represent two different open‐ocean ventilation mechanisms. The first mechanism is the modification of deep ocean properties through local decadal variability of the Labrador Sea deep convective mixing. The second, more novel, mechanism is the climatological convective vertical redistribution of upper central Labrador Sea temperature and salinity anomalies associated with the nonlocal large‐scale subpolar Atlantic Multidecadal Variability and the Atlantic Meridional Overturning Circulation. The ventilated decadal central Labrador Sea signal subsequently spreads into the western subpolar North Atlantic. The results have important implications for predicting decadal ventilated signals in the Labrador Sea that are associated with the large‐scale climate variability.