Giant Iceberg A23a Defies Ocean Currents in Antarctic Waters

Scientists have observed the world's largest iceberg, A23a, which has been spinning in place just north of Antarctica for months, despite being in the path of the powerful Antarctic Circumpolar Current (ACC). This massive iceberg, over twice the size of Greater London, is trapped atop a rotating cylinder of water known as a Taylor Column. A23a broke free from Antarctica in 1986 and remained static for 30 years before starting to drift in 2020. It entered the ACC in April, which was expected to propel it into the South Atlantic. However, it has remained near the South Orkney Islands, rotating anti-clockwise by about 15 degrees a day. This unique behavior delays its decay and eventual melting. Oceanographers explain that the Taylor Column, a phenomenon first described in the 1920s, plays a crucial role in this occurrence. It is formed when an ocean current encounters an obstruction on the seafloor, leading to the creation of a rotating mass of water. In this case, the obstruction is a 100 km-wide bump on the ocean floor known as Pirie Bank. This situation highlights the ocean's dynamic nature and the unexpected behaviors of icebergs. The continued observation of A23a offers valuable insights into oceanic processes and the impact of climate change on polar regions.

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