Altimetry-drived Antarctic Circumpolar Current fronts
An up-to-date map of the Antarctic Circumpolar Current (ACC) fronts is constructed from the latest version of mean dynamic topography from satellite altimetry (Park et al., 2019, Observations of the Antarctic Circumpolar Current over the Udintsev Fracture Zone, the narrowest choke point in the Southern Ocean, JGR-Oceans, in review). These are derived from the 1/8°-resolution Mean Dynamic Topography (MDT) of Centre National d’Etudes Spatiales-Collect Localisation Satellites 2018 (CNES-CLS18) for the 1993-2012 reference period [Rio et al., The new CNES-CLS18 Mean Dynamic Topography solution, in preparation]. The narrowest ACC width in the Udintsev Fracture Zone (UFZ), with the strongest concentration of the three major ACC fronts within a limited distance as short as 170 km, about 40% narrower than that at Drake Passage. At 144°W, at the entrance of the UFZ, which lies between the Pacific-Antarctic Ridge (PAR) and its eastwardly-offset segment (offset PAR segment), there is a triple confluence of the Subantarctic Front (SAF), Polar Front (PF), and Southern ACC Front. Downstream of this longitude, the SAF progressively meanders northward over the relatively shallow offset PAR segment before channeling through the Eltanin Fracture Zone, thus diverging from the PF which proceeds through the UFZ.
-35N, -75S, 180E, -180W