Collaborative Research: Ice Shelf Rifting, Calving, and the Drift of Large icebergs

Project Description
CRAC-ICE will be a coordinated investigation into calving processes on three major Antarctic ice shelves, and a (long-term) monitoring of icebergs in the Southern Ocean, including the study of the physical processes related to iceberg drift and decay. The processes leading to a calving event include the initiation and propagation of through-cutting rifts. Iceberg calving can result in a significant loss of mass from the Antarctic ice sheet, and represents ~ 65% of the total ice sheet ablation. Therefore, it is critical to understand the processes which precede and lead up to a major calving event in order to realistically assess how future climate changes might affect the Antarctic Ice Sheet. Post-calving, iceberg drift is influenced by the shape of the coastline, bottom topography, and a combination of tides, currents, wind, and sea ice. Monitoring the evolution of icebergs as they drift into warmer waters provides a valuable experiment in how rapid climate change influences ice shelves – especially such components as firn compaction, the impact of surface meltwater, ponding, and iceberg break-up. Grounded icebergs cause a severe devastation of the sea floor, forcing benthic communities to re-colonise. Iceberg melting and decay represents a significant source of freshwater (and mineral dust) primarily into the upper layers of the Southern Ocean's northern fringe. A stabilisation of the weakly stratified water column has important and poorly understood consequences for sea ice and water masses involved in deep and bottom water formation, and the biology of the euphotic zone.