Calving of floating ice shelves and icebergs in Antarctica triggered by internal ocean waves driven by marine ice-cliff

Ice calving around Antarctica has a significant impact on glacier dynamics, sea ice, and marine productivity, which in turn affect global sea level and climate.  However, there is limited documented knowledge of the causes of ice calving triggered by internal ocean processes throughout Antarctica, especially during the austral winter.  A total of 3708 iceberg calving events were observed along the circum-Antarctic coastline over a three-month winter period.  These events included the calving of ice cliffs, ice shelves, and icebergs, spanning seven orders of magnitude in spatial scale.  The results suggest that ice cliff calving is primarily driven by internal glacier stresses and is widespread along the Antarctic coast.  The frequency of calving is primarily controlled by glacier ice velocity.  About 70% of the calving in Antarctica occurs on the Antarctic Peninsula.  Internal waves generated by ice cliff calving cascade to small enough scales to induce shear that leads to near-field (~40 km) calving of floating ice shelves and icebergs in regions of high topographic relief.  This study presents a newly discovered mechanism for ice shelf and iceberg calving driven by oceanic forces.  The mechanism has broad applicability and can serve as a catalyst for calving modeling and the study of oceanic internal waves.