Bathymetric controls on calving processes at Pine Island Glacier

• Published in: The Cryosphere
• Main Authors: J. E. Arndt, R. D. Larter, P. Friedl, K. Gohl, K. Höppner, the Science Team of Expedition PS104
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2018
• Subjects: geo; envir; Antarctic; Pine Island Glacier; Antarc*; Ice Shelf; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-12-2039-2018; https://www.the-cryosphere.net/12/2039/2018/tc-12-2039-2018.pdf; https://doaj.org/article/681723af0d884291bc7ac7577d540ec4

Pine Island Glacier is the largest current Antarctic contributor to sea-level rise. Its ice loss has substantially increased over the last 25 years through thinning, acceleration and grounding line retreat. However, the calving line positions of the stabilising ice shelf did not show any trend within the observational record (last 70 years) until calving in 2015 led to unprecedented retreat and changed the alignment of the calving front. Bathymetric surveying revealed a ridge below the former ice shelf and two shallower highs to the north. Satellite imagery shows that ice contact on the ridge was likely lost in 2006 but was followed by intermittent contact resulting in back stress fluctuations on the ice shelf. Continuing ice-shelf flow also led to occasional ice-shelf contact with the northern bathymetric highs, which initiated rift formation that led to calving. The observations show that bathymetry is an important factor in initiating calving events.