The role of Atlantic-Arctic exchange in North Atlantic multidecadal climate variability

Abstract

It has recently been suggested that multidecadal variability in North Atlantic sea surface temperature occurs with two dominant periods. In this paper we investigate the origin of these two time scales in a 500 year control run of the GFDL CM2.1 model. We focus on the exchange between the Atlantic and Arctic oceans and study spectra of temperature, salinity and meridional overturning circulation and the correlations between these quantities. The analysis shows that (i) the shorter period variability originates in the North Atlantic and (ii) the exchange between the Atlantic and Arctic can explain the longer period of multidecadal variability in the North Atlantic