Figure 4: A 145-year-long historic time series of Agulhas leakage.
From: Atlantic multi-decadal oscillation covaries with Agulhas leakage
Annual (grey) and decadally filtered (black) Agulhas leakage (AL) regressed from HadISST and from OISST (purple) using the INALT01 relation (shading shows the 95% confidence interval from the regression, Fig. 3); decadally filtered SAM indices from reanalysis22 (blue solid, correlation with AL (both detrended), r=0.89*) and historic analysis23 (blue dashed, r=0.59**). Agulhas leakage and AMO index (red, HadISST anomaly, averaged between 0°–60° N and 75°–7.5° W) are lag-correlated (r=0.74**) by 15 years (significant at *99%, **95% confidence interval, data detrended. Note that the correlation also holds if the global mean temperature is removed instead of detrending the AMO time series). The AMO uncertainty was estimated using the square mean difference between HadISST and an independent data set (ERSSTv3b (ref. 45)).
