Impact of the Atlantic Meridional Overturning Circulation on Upper Water Temperature of the North Atlantic and the Atlantic Sector of the Arctic Ocean

Abstract

In this study we investigate the impact of variability of the Atlantic Meridional Overturning Circulation (AMOC) on water temperature of the upper 100-m layer of the North Atlantic and Arctic oceans. We use three data-sets (ARMOR-3D, SODA3.4.2 и ORAS4) with different spatial resolution and covering different time periods. The temperature variability is decomposed into its natural modes using Empirical Orthogonal Functions (EOF). The second EOF, which accounts for 20–27% of dispersion of water temperature in the upper ocean, is associated with a change in the AMOC intensity. The time variability of the principal component of this mode has high correlation with the AMOC (0.6–0.9 depending on the data-set and the AMOC index used). The AMOC has the highest impact on water temperature in the Irminger and Labrador seas. The related amplitude of water temperature fluctuations reaches 1.5–2°С in the central part of the Irminger Sea, which is one of the key deep convection regions. Intensification of the AMOC leads to an increase the upper ocean temperature over most of the North Atlantic and Norwegian Sea and to a decrease of water temperature over most of the Greenland Sea, Barents Sea and in an area north of Spitsbergen.