Antarctic Circumpolar Current (ACC)

The Antarctic Circumpolar Current (ACC) is the world’s largest ocean current and the only one that flows unbroken around the globe, driven eastward by the Southern Hemisphere westerlies through Drake Passage. Transport estimates span the canonical 134 Sverdrups from the ISOS program to 173.3 Sv from the cDrake array, with a time-mean near 157 Sv. The flow concentrates in narrow fronts, the Subantarctic Front and Polar Front, where steep density gradients steer it. The ACC connects the Atlantic, Pacific, and Indian basins, forms the upper limb of Southern Ocean overturning, and sets the climate barrier that thermally isolates Antarctica.