Antarctic Bottom Water contraction drives abyssal ocean warming along SAMBA-West line (34.5°S) in the Argentine basin
Santos, D. M. C., T. C. Bilo, et al.
We present an updated assessment of abyssal temperature trends in the Argentine Basin using expanded hydrographic and moored observations from the SAMBA-West line. The study addresses two main questions: (1) What is the spatial distribution of the abyssal warming along the SAMBA-West line? (2) What mechanisms drive the observed changes? Using output from a high-resolution numerical simulation, we first characterize how the abyssal flow near 34.5°S relates to the broader basin-scale circulation, providing context for interpreting the observations. Within this framework, we find that SAMBA-West is situated within a dynamically complex junction of deep boundary currents and recirculation pathways in the northwestern portion of the Argentine Basin. A coherent, statistically significant warming trend is found across most of the array and vertically throughout the AABW layer, primarily due to its vertical contraction, likely reflecting reduced formation or export of the AABW.

