Amery Ice Shelf

Amery Ice Shelf
Name	Amery Ice Shelf
Caption	Satellite image of the Amery Ice Shelf region
Location	Prydz Bay, Mac. Robertson Land, Antarctica
Coordinates	69°S 71°E
Type	Ice shelf
Area	62,620 km2
Length	150 km
Thickness	~1,000 m (root)

Amery Ice Shelf is a large ice shelf in Prydz Bay along the coast of Mac. Robertson Land in Antarctica. It is one of the largest ice shelves on Earth and forms the seaward extension of several major outlet glaciers draining the East Antarctic Ice Sheet. The ice shelf interacts with regional systems such as the Indian Ocean, Aurora Subglacial Basin, and coastal polynyas, influencing local oceanography and global sea level over decadal to centennial timescales.

Geography and Physical Characteristics

The ice shelf occupies the head of Prydz Bay between the Ronne Ice Shelf-distance scale of Antarctic coastal features and landmarks such as Amundsen Sea and Ross Ice Shelf in continental context. It receives inflow from outlet glaciers including Fisher Glacier, Mackay Glacier, and channels draining the Prince Charles Mountains and the Prince Charles Islands vicinity, abutting regions like Mac. Robertson Land and the Vestfold Hills. Surface features include crevasse fields, flow stripes, grounding zones near the law of isostasy-affected coast, and an ice-front that calves into sea ice and icebergs into Prydz Bay and the adjacent Southern Ocean. Ice thickness reaches approximately 1,000 metres at the grounding line with a floating tongue extending hundreds of kilometres, influenced by bathymetry such as the Mac. Robertson Shelf and sub-ice troughs linking to the Aurora Basin.

Glaciology and Dynamics

Ice dynamics are governed by the interaction of upstream ice streams from the East Antarctic Ice Sheet, basal conditions over the Aurora Subglacial Basin, and ocean-driven melting at the ice–ocean interface influenced by Antarctic Circumpolar Current and modified water masses like Circumpolar Deep Water. The shelf exhibits longitudinal stretching, shear margins bordering ice streams, and stick–slip behavior at pinning points like grounded ridges analogous to features studied at Ross Ice Shelf. Internal deformation, basal sliding, and fracture mechanics produce rift systems comparable to those observed at Larsen Ice Shelf and dynamics modeled in studies referencing PISM and ICESat altimetry. Interaction with seasonal polynyas and katabatic winds from the continental interior modulates sea-ice formation and basal freeze-on processes similar to phenomena recorded near McMurdo Sound and Weddell Sea.

History of Exploration and Research

Discovery and mapping involved expeditions such as the British Australian and New Zealand Antarctic Research Expedition and aerial surveys by the U.S. Operation Highjump and Australian National Antarctic Research Expeditions. Research infrastructure supported by institutions like the Australian Antarctic Division, Commonwealth Scientific and Industrial Research Organisation, and universities from Australia and United States has enabled glaciological, geophysical, and oceanographic studies. Remote-sensing campaigns utilized platforms and missions including Landsat, RADARSAT, ICESat, and CryoSat while field efforts incorporated seismic surveys, hot-water drilling akin to methods used at WAIS Divide, and deep-ice coring informed by programs such as EPICA and Dome C investigations.

Climate Change Impacts and Ice Shelf Stability

Assessments of stability consider forcings from atmospheric warming linked to Intergovernmental Panel on Climate Change scenarios and oceanic heat import via the Antarctic Circumpolar Current. Studies compare vulnerability to that observed at the Larsen B Ice Shelf collapse and evaluate buttressing loss effects documented for Pine Island Glacier and Thwaites Glacier. Numerical projections using coupled ice–ocean models and data assimilation from GRACE gravimetry and satellite altimetry estimate contributions to global sea level under Representative Concentration Pathways used by IPCC. Grounding-line migration observed with radar interferometry relates to processes described in the Marine Ice Sheet Instability hypothesis and potential consequences for the East Antarctic Ice Sheet integrity.

Biology and Ecosystems

The sub-ice and marginal marine environment supports specialized communities comparable to those in polynyas near Maud Rise and Ross Sea ecosystems. Microbial assemblages in basal ice and sub-ice cavities resemble extremophiles documented in Lake Vostok and Lake Untersee, while benthic communities beneath calved ice regions include filter-feeders and deposit-feeders studied in Antarctic benthos surveys. Sea-ice-associated fauna such as Emperor penguin colonies, Adélie penguin populations, and krill-dominated trophic links in the Southern Ocean influence higher predators like Antarctic fur seal and migratory species tracked by satellite tagging programs associated with institutions like the British Antarctic Survey.

Human Activities and Infrastructure

Human activities are limited to scientific operations coordinated through bases such as Casey Station and logistical support from platforms tied to national programs including the Australian Antarctic Division, National Science Foundation (United States), and collaborative projects under the Council of Managers of National Antarctic Programs. Airfields, temporary field camps, and oceanographic vessels like icebreakers used in resupply and research mirror operations at Davis Station and Mawson Station, with environmental management governed by the Antarctic Treaty System and protocols arising from the Convention on the Conservation of Antarctic Marine Living Resources.

Notable Events and Calving Episodes

Significant calving events have produced icebergs tracked by agencies using MODIS and ERS imagery, with notable bergs comparable in study to the B-15 iceberg and calving documented at Pine Island Bay. Observed rift propagation and episodic calving have been monitored with InSAR techniques and GPS campaigns, and events impacting polynya dynamics and sea-ice cover have been the subject of analyses in journals and reports by organizations such as SCAR and IAEA-linked environmental monitoring programs.

Category:Ice shelves of Antarctica Category:Geography of Mac. Robertson Land