Fig. 2: Simulated and reconstructed estimates for Agulhas leakage (AL) reveal that AL most likely increased between the mid-1960s and mid-1980s, but yield ambiguous results for the evolution of AL since the 1990s and the absolute transport values.
From: Robust estimates for the decadal evolution of Agulhas leakage from the 1960s to the 2010s
a Absolute AL transport estimates. b Annual (thin lines), as well as sub-decadally filtered (thick lines, 11 yr Hamming window) AL anomalies referenced to the 1964–2005 mean (or the long-term mean for all timeseries not covering the full period). c Moving centered 21year linear AL trends (filled circles mark values that are significant according to two-sided student’s t-test and 95% confidence level). AL estimates are (i) inferred via Lagrangian particle tracking using the full 3D velocity fields (ALLA) simulated in INALT20 under JRA55-do forcing (SIMJRA, SIMJRAo) and CORE forcing (SIMCORE), and obtained from the ocean reanalysis BRAN2020 (REABRAN); (ii) reconstructed from sea surface height following Le Bars et al. (2014)18 using the difference of Agulhas Current and Agulhas Return Current strength calculated from geostrophic velocities (ALSSH) along Topex/Poseidon satellite track T122; (iii) newly obtained from 2D Lagrangian particle tracking using geostrophic velocities from AVISO (ALLA-SSH, details in Supplementary Fig. 2); (iv) reconstructed following Biastoch et al.10 from sea surface temperature (ALSST) using HadISST data; and (v) inferred from observed drifter and float trajectories (ALRichardson, ALDaher; the transparent green shading represents the error estimate provided by Daher et al.32).
