Hydrography and Circulation of Ice-Marginal Lakes at Bering Glacier, Alaska, U.S.A

Josberger, Edward G.; Shuchman, Robert A.; Meadows, Guy; Savage, Sean; Payne, John

doi:10.1657/1523-0430(2006)38[547:hacoil]2.0.co;2

Cited by 11 publications

(14 citation statements)

References 23 publications

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“…Early observations of a surge in 1938-1940 go back to R. M. Krimmel (USGS). Bering Glacier surged again in 1957-1967(Molnia & Post, 2010Post, 1972-1997(Fatland & Lingle, 1998, 2002Fleischer et al, 2010;Herzfeld, 1998;Herzfeld & Mayer, 1997;Josberger et al, 2010;Lingle et al, 1993;Mayer & Herzfeld, 2000;Molnia, 2008;Molnia & Post, 1995Molnia & Williams, 2001;Roush et al, 2003;.…”

Section: 1029/2017jf004341mentioning

confidence: 99%

Crevasses as Indicators of Surge Dynamics in the Bering Bagley Glacier System, Alaska: Numerical Experiments and Comparison to Image Data Analysis

Trantow

Herzfeld

2018

JGR Earth Surface

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One of the largest sources of uncertainty in sea level rise prediction is glacial acceleration, of which the surge phenomenon is the least understood type. The surge of the Bering Bagley Glacier System (BBGS), Alaska, in 2011–2013 has provided a rare opportunity to study the surge phenomenon in a large and complex glacier system. A surge results in widespread crevassing throughout the glacier system complicating many traditional techniques used to study glacier dynamics. In this paper, we utilize crevassing as a means to investigate the recent BBGS surge through numerical modeling and geostatistical data analysis. Following the principles of structural glaciology, image‐based crevasse characterizations are obtained through geostatistical methods applied to Landsat‐7 data, supplemented by airborne field observations. On the modeling side, a 3‐D full‐Stokes finite element model of the BBGS is developed and applied to investigate ice dynamics and surface structures during the recent surge. A von Mises criterion is adopted to simulate crevassing at the glacier surface, oriented along the axes of maximum principal tensile stress. To facilitate evaluation of model‐ and data‐derived crevasse characteristics, three different comparison methods are introduced. General agreement in the model‐data comparisons indicates that the model has the ability to represent the BBGS system during peak acceleration. The crevasse‐based approach is also employed to optimize the basal sliding parameter and the von Mises stress threshold in the model. Results further indicate that bed topography is an important constraint in modeling the surge process.

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Section: 1029/2017jf004341mentioning

confidence: 99%

Crevasses as Indicators of Surge Dynamics in the Bering Bagley Glacier System, Alaska: Numerical Experiments and Comparison to Image Data Analysis

Trantow

Herzfeld

2018

JGR Earth Surface

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“…The water temperature of lakes in contact with a glacier front has been reported in several regions, including Alaska [ Josberger et al ., ; Boyce et al ., ; Trüssel et al ., ], New Zealand [ Hochstein et al ., , ; Warren and Kirkbride , ], Himalaya [ Chikita , ; Chikita et al ., ], and Patagonia [ Haresign and Warren , ]. Most of the study results agree that proglacial lakes are filled with cold water, often colder than 1°C [ Truffer and Motyka , ].…”

Section: Introductionmentioning

confidence: 99%

“…Most of the study results agree that proglacial lakes are filled with cold water, often colder than 1°C [ Truffer and Motyka , ]. In Alaska, the temperature of the lakes was colder than 3°C in front of Mendenhall [ Boyce et al ., ], Yakutat [ Trüssel et al ., ], and Bering Glaciers [ Josberger et al ., ], except for near‐surface shallow layers. These temperatures are significantly lower than that of sea water in front of tidewater glaciers in the same region [ Truffer and Motyka , ].…”

Section: Introductionmentioning

confidence: 99%

Thermal structure of proglacial lakes in Patagonia

et al. 2016

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Calving glaciers are rapidly retreating in many regions under the influence of ice‐water interactions at the glacier front. In contrast to the numerous researches conducted on fjords in front of tidewater glaciers, very few studies have been reported on lakes in which freshwater calving glaciers terminate. To better understand ice‐water interactions at the front of freshwater calving glaciers, we measured lakewater temperature, turbidity, and bathymetry near Glaciar Perito Moreno, Upsala, and Viedma, large calving glaciers of the Southern Patagonia Icefield. The thermal structures of these lakes were significantly different from those reported in glacial fjords. There was no indication of upwelling subglacial meltwater; instead, turbid and cold glacial water discharge filled the region near the lake bottom. This was because water density was controlled by suspended sediment concentrations rather than by water temperature. Near‐surface wind‐driven circulation reaches a depth of ~180 m, forming a relatively warm isothermal layer (mean temperature of ~5–6°C at Perito Moreno, ~3–4°C at Upsala, and ~6–7°C at Viedma), which should convey heat energy to the ice‐water interface. However, the deeper part of the glacier front is in contact with stratified cold water, implying a limited amount of melting there. In the lake in front of Glaciar Viedma, the region deeper than 120 m was filled entirely with turbid and very cold water at pressure melting temperature. Our results revealed a previously unexplored thermal structure of proglacial lakes in Patagonia, suggesting its importance in the subaqueous melting of freshwater calving glaciers.

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“…The terminus of Bering Glacier is partially terrestrial and partially lacustrine. Although Vitus Lake contains brackish water and exhibits tidal influence [ Josberger et al , 2006], the glacier does not calve icebergs into the sea.…”

Section: Introductionmentioning

confidence: 99%

Iceberg calving as a primary source of regional‐scale glacier‐generated seismicity in the St. Elias Mountains, Alaska

et al. 2010

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[1] Since the installation of the Alaska Regional Seismic Network in the 1970s, data analysts have noted nontectonic seismic events thought to be related to glacier dynamics. While loose associations with the glaciers of the St. Elias Mountains have been made, no detailed study of the source locations has been undertaken. We performed a two-step investigation surrounding these events, beginning with manual locations that guided an automated detection and event sifting routine. Results from the manual investigation highlight characteristics of the seismic waveforms including single-peaked (narrowband) spectra, emergent onsets, lack of distinct phase arrivals, and a predominant cluster of locations near the calving termini of several neighboring tidewater glaciers. Through these locations, comparison with previous work, analyses of waveform characteristics, frequency-magnitude statistics and temporal patterns in seismicity, we suggest calving as a source for the seismicity. Statistical properties and time series analysis of the event catalog suggest a scale-invariant process that has no single or simple forcing. These results support the idea that calving is often a response to short-lived or localized stress perturbations. Our results demonstrate the utility of passive seismic instrumentation to monitor relative changes in the rate and magnitude of iceberg calving at tidewater glaciers that may be volatile or susceptible to ensuing rapid retreat, especially when existing seismic infrastructure can be used.Citation: O'Neel, S., C. F. Larsen, N. Rupert, and R. Hansen (2010), Iceberg calving as a primary source of regional-scale glacier-generated seismicity in the St. Elias Mountains, Alaska,

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Hydrography and Circulation of Ice-Marginal Lakes at Bering Glacier, Alaska, U.S.A

Cited by 11 publications

References 23 publications

Crevasses as Indicators of Surge Dynamics in the Bering Bagley Glacier System, Alaska: Numerical Experiments and Comparison to Image Data Analysis

Crevasses as Indicators of Surge Dynamics in the Bering Bagley Glacier System, Alaska: Numerical Experiments and Comparison to Image Data Analysis

Thermal structure of proglacial lakes in Patagonia

Iceberg calving as a primary source of regional‐scale glacier‐generated seismicity in the St. Elias Mountains, Alaska

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