Calving glaciers and ice shelves

Abstract

Calving, or the release of icebergs from glaciers and floating ice shelves, is an important process transferring mass into the world's oceans. Calving glaciers and ice sheets make a large contribution to sea-level rise, but large uncertainty remains about future ice sheet response to alternative carbon scenarios. In this review, we summarize recent progress in understanding calving processes and representing them in the models needed to predict future ice sheet evolution and sea-level rise. We focus on two main types of calving models: (1) discrete element models that represent ice as assemblages of particles linked by breakable bonds, which can explicitly simulate fracture and calving processes; and (2) continuum models, in which calving processes are parameterized using simple calving laws. With a series of examples using both synthetic and real-world ice geometries, we show how explicit models are yielding a detailed, process-based understanding of system physics that can be translated into predictive capability via improved calving laws.

Cosmogenic isotope measurements from recently deglaciated bedrock as a new tool to decipher changes in Greenland Ice Sheet size

“…While implementation and treatment of calving in ice sheet models continues to improve (e.g. Benn and Åström, 2018), our results highlight that inclusion of calving is necessary towards fully understanding ice-margin sensitivity to climate change in the KNS region. Yet, it is difficult to properly simulate calving in paleoclimate ice-sheet model setups that use coarse resolution grids, because fjord systems in Greenland are typically <5km and high-resolution grids (1 km) are necessary to capture grounding line migration .…”

Changes in a Giant Iceberg Created from the Collapse of the Larsen C Ice Shelf, Antarctic Peninsula, Derived from Sentinel-1 and CryoSat-2 Data

“…Iceberg A68 had a length of 160 km and width of 50 km when it was released from the ice shelf. The thickness and weight of the iceberg was presumed to be approximately 300 m and 1 trillion tons, respectively [20]. Shortly after A68 separated from the Larsen C Ice Shelf, it split into two major pieces-A68A and A68B.…”

“…In July 2017, a supersized iceberg broken away from the Larsen C Ice Shelf in the Antarctic Peninsula, named A68 by the NIC. The initial area of the A68 was about 5800 km 2 when it calved [20], which accounts for approximately 10% of the Larsen C Ice Shelf [21,22]. Based on the iceberg tracking database operated by the Brigham Young University and NIC, iceberg A68 is currently the largest iceberg in Antarctica and the sixth largest on satellite observation records.…”

Monitoring Greenland ice sheet buoyancy-driven calving discharge using glacial earthquakes

“…Ice front disintegration becomes more likely as the glacier approaches flotation due to thinning/stretching from steepening stress gradients caused by front acceleration. Once the glacier reaches flotation, full-depth fracture penetration is allowed because high water pressures in basal crevasses can offset the stabilizing effect of ice overburden pressure (Van der Veen, 1998; Benn and others, 2007; Murray and others, 2015c; Benn and Åström, 2018). Although smaller calving events may happen and still contribute to the discharge (e.g.…”