An Intensive Observation of Calving at Helheim Glacier, East Greenland

Holland, David M.; Voytenko, Denis; Christianson, Knut; Dixon, Timothy H.; Mei, Maofei; Parizek, B. R.; Vaňková, Irena; Walker, R. T.; Walter, J. I.; Nicholls, Keith W.; Holland, Daniel M.

doi:10.5670/oceanog.2016.98

Cited by 19 publications

(20 citation statements)

References 67 publications

(89 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the meantime, the nascent iceberg starts rising upward promoting crevasse enlargement. Nontabular calving has strong implications for glacier dynamic response and stability as such events cause glacier speed-up over 4–5 days (Joughin and others, 2008a; Nettles and others, 2008; Rosenau and others, 2013; Holland and others, 2016).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

View full text Add to dashboard Cite

Since the 2000s, Greenland ice sheet mass loss has been accelerating, followed by increasing numbers of glacial earthquakes (GEs) at near-grounded glaciers. GEs are caused by calving of km-scale icebergs which capsize against the terminus. Seismic record inversion allows a reconstruction of the history of GE sources which captures capsize dynamics through iceberg-to-terminus contact. When compared with a catalog of contact forces from an iceberg capsize model, seismic force history accurately computes calving volumes while the earthquake magnitude fails to uniquely characterize iceberg size, giving errors up to 1 km3. Calving determined from GEs recorded ateight glaciers in 1993–2013 accounts for up to 21% of the associated discharge and 6% of the Greenland mass loss. The proportion of discharge attributed to capsizing calving may be underestimated by at least 10% as numerous events could not be identified by standard seismic detections (Olsen and Nettles, 2018). While calving production tends to stabilize in East Greenland, Western glaciers have released more and larger icebergs since 2010 and have become major contributors to Greenland dynamic discharge. Production of GEs and calving behavior are controlled by glacier geometry with bigger icebergs being produced when the terminus advances in deepening water. We illustrate how GEs can help in partitioning and monitoring Greenland mass loss and characterizing capsize dynamics.

show abstract

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

View full text Add to dashboard Cite

show abstract

“…[30,59,61,68,81,85]). Exciting new opportunities have been created by the advent of remotely controlled or autonomous vehicles [86,87].…”

Section: Conclusion and Priorities For Future Researchmentioning

confidence: 99%

Glacier Calving in Greenland

Benn

Cowton

Todd

et al. 2017

Curr Clim Change Rep

View full text Add to dashboard Cite

In combination, the breakaway of icebergs (calving) and submarine melting at marine-terminating glaciers account for between one third and one half of the mass annually discharged from the Greenland Ice Sheet into the ocean. These ice losses are increasing due to glacier acceleration and retreat, largely in response to increased heat flux from the oceans. Behaviour of Greenland's marine-terminating ('tidewater') glaciers is strongly influenced by fjord bathymetry, particularly the presence of 'pinning points' (narrow or shallow parts of fjords that encourage stability) and overdeepened basins (that encourage rapid retreat). Despite the importance of calving and submarine melting and significant advances in monitoring and understanding key processes, it is not yet possible to predict the tidewater glacier response to climatic and oceanic forcing with any confidence. The simple calving laws required for ice-sheet models do not adequately represent the complexity of calving processes. New detailed process models, however, are increasing our understanding of the key processes and are guiding the design of improved calving laws. There is thus some prospect of reaching the elusive goal of accurately predicting future tidewater glacier behaviour and associated rates of sea-level rise.

show abstract

“…At the 20–30 m threshold, ice blocks are nearly free of basal friction, detach from the front, rotate, and roll away into the ocean. This form of calving produces the largest icebergs in Illulissat, Torssukatak, and other fjords (Holland et al, ; Joughin et al, ). As ice advances past the sill of AVA, the bed elevation drops rapidly, the threshold is easily exceed, and ice blocks calve to maintain a stable calving front.…”

Section: Discussionmentioning

confidence: 99%

A Century of Stability of Avannarleq and Kujalleq Glaciers, West Greenland, Explained Using High‐Resolution Airborne Gravity and Other Data

Rignot

Mouginot

et al. 2018

Geophysical Research Letters

View full text Add to dashboard Cite

The evolution of Greenland glaciers in a warming climate depends on their depth below sea level, flow speed, surface melt, and ocean‐induced undercutting at the calving front. We present an innovative mapping of bed topography in the frontal regions of Sermeq Avannarleq and Kujalleq, two major glaciers flowing into the ice‐choked Torssukatak Fjord, central west Greenland. The mapping combines a mass conservation algorithm inland, multibeam echo sounding data in the fjord, and high‐resolution airborne gravity data at the ice‐ocean transition where other approaches have traditionally failed. We obtain a reliable, precision (±40 m) solution for bed topography across the ice‐ocean boundary. The results reveal a 700 m deep fjord that abruptly ends on a 100–300 m deep sill along the calving fronts. The shallow sills explain the presence of stranded icebergs, the resilience of the glaciers to ocean‐induced undercutting by warm Atlantic water, and their remarkable stability over the past century.

show abstract

An Intensive Observation of Calving at Helheim Glacier, East Greenland

Cited by 19 publications

References 67 publications

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

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

Glacier Calving in Greenland

A Century of Stability of Avannarleq and Kujalleq Glaciers, West Greenland, Explained Using High‐Resolution Airborne Gravity and Other Data

Contact Info

Product

Resources

About