ANTARCTICA AND THE SOUTHERN OCEAN

Abstract

Antarctica and the Southern Ocean were dominated by below-average pressure and stronger than average circumpolar westerly winds through much of 2021, resulting in many new low-pressure records set across the continent. The low pressure that gripped the polar cap extended vertically through the troposphere and stratosphere and was accompanied by a persistently strong and stable polar vortex. This helped deliver the coldest winter on record to the South Pole (see Sidebar 6.1) and also helped maintain one of the longest-lived ozone holes on record (second only to the 2020 ozone hole), which did not close until 23 December. Despite the long duration of the ozone hole, its size and the minimum ozone concentrations did not reach exceptional levels, and its slow growth rate in 2021 is consistent with ongoing recovery trends.