Distribution and Transport of Antarctic Winter Water Biogeochemical Properties

Abstract Antarctic Winter Water (WW) forms in the surface mixed layer south of the Antarctic Polar Front and moves subsurface on seasonal timescales. Here, we use biogeochemical‐Argo float data to investigate the circumpolar patterns of the biogeochemical properties of subsurface Winter Water (sWW). Biogeochemical and physical properties of sWW have a seasonal cycle, with sWW persisting on interannual timescales, as well as geographic variability shaped by large‐scale circulation features of the Southern Ocean. Advective processes associated with mesoscale and submesoscale dynamics fueled by the Polar Front influence the equatorward subduction of sWW and its associated biogeochemical properties. This is in contrast to the traditional view that WW evolution is controlled solely by seasonal restratification. WW plays an important role in the climate system because it connects air‐sea fluxes to biogeochemical properties in the interior in the mid‐ and high‐latitudes across the Southern Hemisphere.