Twenty-First Century Calving Retreat of Tasman Glacier, Southern Alps, New Zealand

Dykes, Robert C.; Brook, Martin; Robertson, Clare; Fuller, Ian C.

doi:10.1657/1938-4246-43.1.1

Cited by 39 publications

(34 citation statements)

References 36 publications

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“…A gentle surface slope reduces the gravitational stresses, while narrow valley sidewalls constrict glacier flow by providing substantial lateral drag (Benn et al, 2007a;Koppes et al, 2011), both of which limit flow speeds. Near-terminus flow speeds at Bridge Glacier are 1 to 2 orders of magnitude smaller than those observed at larger tidewater calving glaciers in Patagonia and Alaska (Rivera et al, 2012;Koppes et al, 2011;Meier and Post, 1987;Motyka et al, 2003) and reflect a smaller mass turnover, similar to lake-terminating glaciers Mendenhall and Tasman (Boyce et al, 2007;Dykes et al, 2011).…”

Section: Controls On Calvingmentioning

confidence: 76%

“…Most of the research exploring the dynamics of lake-calving glacier systems has focused on a few major regions: Alaskan glaciers Mendenhall and Yakutat (Motyka et al, 2002;Boyce et al, 2007;Trüssel et al, 2013), Tasman Glacier in the Southern Alps of New Zealand (Warren and Kirkbride, 2003;Dykes and Brook, 2010;Dykes et al, 2011), and several glaciers along the Patagonian Hielo Sur, most notably Perito Moreno, Nef, and Upsala glaciers (Warren et al, 2001;Stuefer et al, 2007;Sakakibara et al, 2013). Here we present new data from Bridge Glacier, a laketerminating outlet glacier of the Lillooet Ice field in the Coast Mountains of British Columbia, Canada.…”

Section: Introductionmentioning

confidence: 92%

“…Dyurgerov and Meier, 2005;Radić and Hock, 2011;Gardner et al, 2013;Zemp et al, 2015). Although this retreat has been irregular, a general trend of 20th century retreat is pervasive and well correlated with an increase in global mean temperatures (Oerlemans, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…This blurring of the climate-glacier signal is due to calving, which can be an important additional source of ablation (Benn et al, 2007a), and makes predictions of future retreat more difficult (Van der Veen, 2002;Motyka et al, 2002). However, the potential for calving glaciers to lose large volumes of ice over single seasons (even during years of positive mass balance) suggests that they can contribute disproportionately to eustatic sea level rise (Meier and Post, 1987;Dyurgerov and Meier, 2005), highlighting their important role in glacier response to climate.…”

Section: Introductionmentioning

confidence: 99%

“…The long-term retreat of calving glaciers has been found to follow a step-like pattern in which periods of stability are followed by a dramatic retreat, often coinciding with terminus flotation (Warren and Kirkbride, 2003;Boyce et al, 2007;Dykes et al, 2011). In many cases, flotation is achieved through thinning near the terminus due to successive years of high melt rates.…”

Section: Introductionmentioning

confidence: 99%

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Ablation from calving and surface melt at lake-terminating Bridge Glacier, British Columbia, 1984–2013

Chernos¹,

Koppes²,

Moore³

2016

The Cryosphere

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Abstract. Bridge Glacier is a lake-calving glacier in the Coast Mountains of British Columbia and has retreated over 3.55 km since 1972. The majority of this retreat has occurred since 1991. This retreat is substantially greater than what has been inferred from regional climate indices, suggesting that it has been driven primarily by calving as the glacier retreated across an overdeepened basin. In order to better understand the primary drivers of ablation, surface melt (below the equilibrium line altitude, ELA) and calving were quantified during the 2013 melt season using a distributed energy balance model (DEBM) and time-lapse imagery. Calving, estimated using areal change, velocity measurements, and assuming flotation were responsible for 23 % of the glacier's ablation below the ELA during the 2013 melt season and were limited by modest flow speeds and a small terminus cross-section. Calving and surface melt estimates from 1984 to 2013 suggest that calving was consistently a smaller contributor of ablation. Although calving was estimated to be responsible for up to 49 % of the glacier's ablation for individual seasons, averaged over multiple summers it accounted between 10 and 25 %. Calving was enhanced primarily by buoyancy and water depths, and fluxes were greatest between 2005 and 2010 as the glacier retreated over the deepest part of Bridge Lake. The recent rapid rate of calving is part of a transient stage in the glacier's retreat and is expected to diminish within 10 years as the terminus recedes into shallower water at the proximal end of the lake. These findings are in line with observations from other lake-calving glacier studies across the globe and suggest a common large-scale pattern in calving-induced retreat in lake-terminating alpine glaciers. Despite enhancing glacial retreat, calving remains a relatively small component of ablation and is expected to decrease in importance in the future. Hence, surface melt remains the primary driver of ablation at Bridge Glacier and thus projections of future retreat should be more closely tied to climate.

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Section: Controls On Calvingmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ablation from calving and surface melt at lake-terminating Bridge Glacier, British Columbia, 1984–2013

Chernos¹,

Koppes²,

Moore³

2016

The Cryosphere

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New Zealand

2016

Recent Climate Change Impacts on Mountain Glaciers

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Streamflow response to the rapid retreat of a lake‐calving glacier

Moyer

Moore

Koppes

2016

Hydrological Processes

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There has been increasing attention over the last decade to the potential effects of glacier retreat on downstream discharge and aquatic habitat. This study focused on streamflow variability downstream of Bridge Glacier in the southern Coast Mountains of BC between 1979 and 2014, prior to and during a period in which the glacier experienced enhanced calving and rapid retreat across a lake‐filled basin. Here we combined empirical trend detection and a conceptual‐parametric hydrological model to address the following hypotheses: (1) streamflow trends in late summer and early autumn should reflect the opposing influences of climatic warming (which would tend to increase unit‐area meltwater production) and the reduction in glacier area (which would tend to reduce the total volume of meltwater generated), and (2) winter streamflow should increase because of displacement of lake water as ice flows past the grounding line and calves into the lake basin. In relation to the first hypothesis, we found no significant trends in monthly discharge during summer. However, applying regression analysis to account for air temperature and precipitation variations, weak but statistically significant negative trends were detected for August and melt season discharge. The HBV‐EC model was applied using time‐varying glacier cover, as derived from Landsat imagery. Relative to simulations based on constant glacier extent, model results indicated that glacier recession caused a decline in mean monthly streamflow of 9% in August and 11% in September. These declines in late‐summer streamflow are consistent with the results from our empirical analysis. The second hypothesis is supported by the finding of positive trends for December, January, and February discharge. Despite the modelled declines in late‐summer mean monthly streamflow, recorded discharge data exhibited neither positive nor negative trends during the melt season, suggesting that Bridge Glacier may currently be at or close to the point of peak water. Further analysis of the impact of lake‐terminating glaciers on downstream discharge is needed to refine the peak water model. Copyright © 2016 John Wiley & Sons, Ltd.

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Twenty-First Century Calving Retreat of Tasman Glacier, Southern Alps, New Zealand

Cited by 39 publications

References 36 publications

Ablation from calving and surface melt at lake-terminating Bridge Glacier, British Columbia, 1984–2013

Ablation from calving and surface melt at lake-terminating Bridge Glacier, British Columbia, 1984–2013

New Zealand

Streamflow response to the rapid retreat of a lake‐calving glacier

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