Abstract

The ocean is in constant motion, with water circulating within and flowing between basins. As the water moves around, it caries heat and nutrients, as well as larger objects like planktonic marine species and litter around the globe.

The most natural way to study the pathways of water and the connections between ocean basins is in a Lagrangian framework, where the ocean circulation is traced out using particle trajectories. The trajectories can come from either numerical integration of virtual floats in high-resolution ocean models, or from the paths of free-flowing observational drifters (surface buoys or Argo floats) in the real ocean.

In this presentation, I will show some examples of Lagrangian-derived pathways in the Southern Ocean. I will show preliminary results on drifting buoy separation in the pacific Sector of the Southern Ocean, as well as discuss how these drifting buoys can be used to create a statistical model of the surface circulation that can be used to study the drift of marine litter.

Finally, I will discuss the pathways of the different varieties of Antarctic Bottom Water (AABW) from their source regions around Antarctica to the abyssal subtropical basins using Lagrangian particles in the SOSE model. In particular, I will show how the mixing ratios of the different source types of AABW are similar once it reaches the three subtropical basins. This is suggestive of an amalgamation of the different source waters in the Southern Ocean, which we show is related to vigorous deep eddy mixing around 50S.