Are North Atlantic Multidecadal SST Anomalies Westward Propagating?

The westward propagation of sea surface temperature (SST) anomalies is one of the main characteristics of one of the theories of the Atlantic Multidecadal Oscillation. Here we use techniques from complex network modeling to investigate the existence of the westward propagation in the North Atlantic SST observations. We construct Climate Networks (CNs) by using a linear Pearson correlation measure (resulting in Pearson Correlation Climate Network (PCCNs)) and a (nonlinear) mutual information measure (resulting in Mutual Information Climate Network (MICNs)) of spatial correlations between SST variations. Analysis of the topological properties of both types of CNs shows that the MICNs are better in capturing the main features of propagating patterns from the noisy SST data than PCCNs and that westward propagation of multidecadal SST anomalies indeed seems to occur in the North Atlantic.