When, in the foreseeable future, a tabular iceberg nearly seven times the size of Berlin breaks off the Larsen C Ice Shelf in the Antarctic, it will begin a journey, the course of which climate researchers at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) can accurately predict. The researchers have now succeeded in modelling how Antarctic icebergs drift through the Southern Ocean, and in identifying the physical factors behind their movement and their melting.
On the Larsen C Ice Shelf, a massive iceberg has begun to break off from the rest. Further, at ca. 1,300 gigatonnes, the colossus will weigh nearly as much as all of the new icebergs formed in the Antarctic in the course of an average year.
It is virtually impossible to predict exactly when ice masses of this size will calve. Climate researchers at the Alfred Wegener Institute can now better predict how small, medium-sized, and large icebergs will drift through the Southern Ocean once they have broken off from their ice shelf, and which physical factors are responsible for their movements– these factors can vary greatly, depending on their size.
1Winds blow the dwarfs out to the open sea, while the giants remain near the coast
” Icebergs that aren’t longer or wider than two kilometres normally drift away from the ice shelf edge and out of coastal waters within a few months. The wind pushes them out to the open sea, where they ultimately break up into smaller pieces and melt in the course of two to three years,” explains Thomas Rackow, a climate modeller at the Alfred Wegener Institute in Bremerhaven/Germany and first author of the new study.
Instead, the icebergs’ motion is chiefly driven by their own weight, and by the fact that the surface of the Southern Ocean is not flat, but instead leans typically to the north. As Rackow elaborates, “When large icebergs drift, they initially slide down the inclined ocean surface, but not along a straight line; they tend to veer to the.