Multidecadal Variability of Hydro-Thermodynamic Characteristics and Heat Fluxes in North Atlantic

Abstract

The article describes a manifestation of Atlantic multidecadal oscillation (AMO) in the variability of hydro-thermodynamic characteristics and ocean surface heat fluxes in North Atlantic. It is shown that multidecadal changes in the upper mixed layer temperature and mixed layer depth, as well as sea surface height (SSH), are statistically significant and show physically consistent changes. Convective mixing of waters at high latitudes is stronger for negative AMO phase with an exception the case of Great Salinity Anomaly. Large-scale fluctuations in SSH are most pronounced in the eastern part of North Atlantic. Multidecadal changes in the net surface heat fluxes and horizontal heat advection are coherent. The increase (decrease) of horizontal heat advection in the negative (positive) AMO phase leads to an increase (decrease) of the ocean heat release to the atmosphere. Multidecadal variability of the horizontal heat advection is due to changes in the dynamics of currents, rather than temperature gradients.