 Antarctic Circumpolar Current

The Antarctic Circumpolar Current is the eastward ocean circulation encircling Antarctica and connecting the Atlantic, Indian and Pacific oceans. Its direction differs from the predominantly westward Antarctic Coastal Current closer to the continent. Wind stress, oceanic density gradients and seabed geometry shape the current; it is not a single uniform-speed ring.^[ref][ref]

The current illustrates why ocean dynamics require both forcing and boundaries. Atmospheric winds supply momentum, geostrophic balance relates much of the large-scale flow to horizontal pressure gradients, and underwater ridges redirect its path. Measuring the current therefore involves velocity and water-column structure across a section, rather than tracking one surface parcel and assigning that speed to the entire ocean.