In July 2017, one of the largest icebergs on record calved from the Larsen C ice shelf in Antarctica. However, sea ice to the east and shallow waters to the north kept this giant berg, named A68, hemmed in. So for more than a year it wafted to and fro, but never left its parent ice shelf’s side. Strong winds blowing from Larsen C have finally given it the push it was waiting for. In early September 2018, these winds pushed the southern end of the berg out into the Weddell Gyre. This clockwise drift of ocean waters and sea ice flowing north past the Larsen shelf, which can be seen in the animation as a flow from right to left, has rotated A68 out into the Weddell Sea. Here it is freer to float away and be carried further north into warmer waters.

The animation, generated by Adrian Luckman at Swansea University, uses data from the Copernicus Sentinel-1mission – a two-satellite constellation. Each satellite carries an advanced radar instrument that can image Earth’s surface through cloud and rain and regardless of whether it is day or night. This is essential for monitoring the polar regions, which are shrouded in darkness during the long winter months.