Observed and simulated variability of the AMOC at 26°N and 41°N

Timeseries of the observational estimate of the Atlantic meridional overturning circulation (AMOC) have recently become available, but so far no contemporaneous relation has been documented between them. Here, we analyze the variability of the 26°N RAPID and the 41°N ARGO-based AMOC estimates on seasonal timescales, and we compare them to a simulation from a high-resolution NCEP-forced ocean model. In our analysis of the observed timeseries, we find that the seasonal cycles of the non-Ekman component of the AMOC between 26°N and 41°N are 180-degrees out-of-phase. Removing the mean seasonal cycle from each timeseries, the residuals have a non-stationary covariability. Our results demonstrate that the AMOC is meridionally covariable between 26°N and 41°N at seasonal timescales. We find the same covariability in the model, though the phasing differs from the observed phasing. This may offer the possibility of inferring AMOC variations and associated climate anomalies throughout the North Atlantic from discontinuous observations.