A Review of Recent Changes in Major Marine-Terminating Outlet Glaciers in Northern Greenland

Hill, Emily A.; Carr, J. Rachel; Stokes, Chris R.

doi:10.3389/feart.2016.00111

Cited by 69 publications

(96 citation statements)

References 120 publications

(390 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The outlet glaciers of North Greenland drain 40% of the Greenland Ice Sheet (Hill et al, ). At present, discharge from this region is low relative to other sectors due to the slow flow of its marine‐terminating glaciers (Mouginot et al, ; Mankoff et al, ).…”

Section: Introductionmentioning

confidence: 99%

Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

Solgaard

Simonsen

Grinsted

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

We use remotely sensed ice velocities in combination with observations of surface elevation and glacier area change to investigate the dynamics of Hagen Bræ, North Greenland in high detail over the last 35 years. From our data, we can establish for the first time that Hagen Bræ is a surge‐type glacier with characteristics of both Alaskan‐ and Svalbard‐type surging glaciers. We argue that the observed surge was preconditioned by the glacier geometry and triggered by englacially stored meltwater. At present, the glacier is in a transitional state between active and quiescence phases and is not building up to its pre‐surge geometry. We suggest that the glacier is adjusting to the loss of its floating section, general thinning, and changes in fjord conditions that occurred over the study period which are unrelated to the surge behavior. The high temporal resolution of the ice velocity data gives insight to the sub‐annual glacier flow.

show abstract

Section: Introductionmentioning

confidence: 99%

Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

Solgaard

Simonsen

Grinsted

et al. 2020

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…This means that the addition of a subglacial hydrology might have the potential to improve the results considerably. While many glaciers in Greenland have regularly draining supraglacial lakes and run-off driving a seasonality of the flow velocities, little is known about the effect at NEGIS (Hill et al, 2017).…”

mentioning

confidence: 99%

A confined–unconfined aquifer model for subglacial hydrology and its application to the North East Greenland Ice Stream

Beyer¹,

Kleiner²,

Aizinger³

et al. 2017

Preprint

View full text Add to dashboard Cite

Abstract. Subglacial hydrology plays an important role in the ice sheet dynamics as it determines the sliding velocity of ice sheets and also drives freshwater into the ocean. Modeling subglacial water has been a challenge for decades, and only recently new approaches have been developed such as representing subglacial channels and thin water sheets by separate layers of variable permeability. We extend this concept by modeling a confined and unconfined aquifer system (CUAS) in a single layer. The advantage of this formulation is that it prevents unphysical values of pressure at reasonable computational 5 cost. We also performed sensitivity tests to investigate the effect of different model parameters. The strongest influence of model parameters was detected in terms governing the opening and closure of channels. Furthermore, we applied the model to the North East Greenland Ice Stream, where an efficient system independent of seasonal input was identified about 500 km downstream from the ice divide. Using the effective pressure from the hydrology model in the Ice Sheet System Model (ISSM) shows considerable improvements of modeled velocities in the coastal region.

show abstract

“…Variations in basal topography and fjord width have been previously identified as an important control on the dynamic response of glaciers in many regions of the GrIS Howat and Eddy, 2011;McFadden et al, 2011;Thomas et al, 2009;Carr et al, 2017). In this study, the differences between periods of retreat, acceleration, and thinning between floating and grounded-terminus glaciers suggests basal topography may control the time taken for glaciers to return to a point where retreat 5 slows and velocities return to pre-retreat levels.…”

Section: Influence Of Glacier Geometrymentioning

confidence: 58%

“…This region is also characterised by large fjord-terminating outlet glaciers, many of which terminate in kilometres-long floating ice tongues, while several others are potentially surgetype (Hill et al, 2017;Joughin et al, 1996;Reeh et al, 2003;Rignot et al, 2001). However, far fewer studies have focussed on northern Greenland, except for at Petermann and the Northeast Greenland Ice Stream (NEGIS) (e.g.…”

mentioning

confidence: 99%

“…We evaluate the dynamic response of glaciers in the region to observed changes at the terminus, focusing on the influence of the presence or absence of floating ice tongues. Our study region includes 18 major marine-terminating outlet 30 glaciers (Figure 1), which are the main outlets in the region, and together drain approximately 40% of the GrIS by area (Hill et al, 2017;Rignot and Kanagaratnam, 2006). First, we provide a multi-decadal record of annual terminus positions between 1948 and 2015 to assess long-term change.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Dynamic changes in outlet glaciers in northern Greenland from 1948 to 2015

Hill¹,

Carr²,

Stokes³

et al. 2018

Preprint

Self Cite

View full text Add to dashboard Cite

The Greenland Ice Sheet (GrIS) is losing mass in response to recent climatic and oceanic warming. Since the mid-1990s, marine-terminating outlet glaciers across the GrIS have retreated, accelerated and thinned, but recent changes in northern 10Greenland have been comparatively understudied. Consequently, the dynamic response (i.e. changes in surface elevation and velocity) of these outlet glaciers to changes at their termini, particularly calving from floating ice tongues, remains unknown.Here we use satellite imagery and historical maps to produce an unprecedented 68-year record of terminus change across 18 major outlet glaciers and combine this with previously published surface elevation and velocity datasets. Overall, recent (1995Overall, recent ( -2015 retreat rates were higher than at any time in the previous 47 years, but change-point analysis reveals three categories of 15 frontal position change: (i) minimal change followed by steady and continuous retreat, (ii) minimal change followed by a switch to a period of short-lived rapid retreat, (iii) glaciers that underwent cycles of advance and retreat. Furthermore, these categories appear to be linked to the terminus type, with those in category (i) having grounded termini and those in category (ii) characterised by floating ice tongues. We interpret glaciers in category (iii) as surge-type. Glacier geometry (e.g. fjord width and basal topography) is also an important influence on the dynamic re-adjustment of glaciers to changes at their termini. 20Taken together, the loss of several ice tongues and the recent acceleration in the retreat of numerous marine-terminating glaciers suggests northern Greenland is undergoing rapid change and could soon impact on some large catchments that have capacity to contribute an important component to sea level rise.

show abstract

A Review of Recent Changes in Major Marine-Terminating Outlet Glaciers in Northern Greenland

Cited by 69 publications

References 120 publications

Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

A confined–unconfined aquifer model for subglacial hydrology and its application to the North East Greenland Ice Stream

Dynamic changes in outlet glaciers in northern Greenland from 1948 to 2015

Contact Info

Product

Resources

About