Observing the disintegration of the A68A iceberg from space
Anne Braakmann-Folgmann, Andrew Shepherd, Laura Gerrish, Jamie Izzard, A. Ridout
Abstract
Icebergs impact the physical and biological properties of the ocean where they drift, depending on the degree of melting. We use satellite imagery and altimetry to quantify the area, thickness, and volume change of the massive A68A iceberg from its calving off the Larsen-C Ice Shelf in July 2017 until January 2021, when it disintegrated. A68A thinned from 235 ± 9 to 168 ± 10 m, on average, and lost 802 ± 34 Gt of ice in 3.5 years, 254 ± 17 Gt of which was through basal melting (a lower bound for the immediate fresh water input into the ocean). Basal melting peaked at 7.2 ± 2.3 m/month in the Northern Scotia Sea and an estimated 152 ± 61 Gt of freshwater was released off South Georgia, potentially altering the local ocean properties, plankton occurrence and conditions for predators.