Surface Expression and Apparent Timing of Subglacial Lake Oscillations Controlled by Viscous Ice Flow

Stubblefield, A. G.; Creyts, T. T.; Kingslake, J.; Siegfried, Matthew R.; Spiegelman, Marc

doi:10.1029/2021gl094658

Cited by 8 publications

(8 citation statements)

References 53 publications

(40 reference statements)

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“…We estimate subglacial lake volumes by assuming that the subglacial lake volume changes are directly transferred to the surface topography. While this is an approximation, the study by Stubblefield et al (2021) supports this, demonstrating that at an ice thickness of ∼1 km (500 m -1.2 km at our study sites) and draining time of less than half a year (we find it to be within weeks at study sites), the volume of the lake and the collapse basin will be almost the same. We derive the collapse basin volume by grid point within the outline is summed to provide a total basin volume.…”

Section: Subglacial Lake Volumessupporting

confidence: 64%

“…Active subglacial lakes, may on the other hand be identified by ice surface collapse basins (surface depressions) created when the lake drains, and localised surface uplift as the lake refills. The surface expressions of subglacial lake volume oscillations are controlled by viscous ice flow (Stubblefield et al, 2021). Only four of the known subglacial lakes in Greenland have been identified by ice surface collapse basins, while the rest are identified by the use of RES (Bowling et al, 2019).…”

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confidence: 99%

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Improved Monitoring of Subglacial Lake Activity in Greenland

Sørensen

Bahbah

Simonsen

et al. 2023

Preprint

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Abstract. Subglacial lakes form beneath ice sheets and ice caps if water is available, and if bedrock and surface topography are able to retain the water. On a regional scale, the lakes modulate the timing and rate of freshwater flow through the subglacial system to the ocean by acting as reservoirs. More than one hundred hydrologically active subglacial lakes, that drain and recharge periodically, have been documented under the Antarctic ice sheet, while only a handful of active lakes have been identified in Greenland. The small size of the Greenlandic subglacial lakes puts additional demands on mapping capabilitie aiming to resolve the evolving surface topography in sufficient detail to record their temporal behavior. Here, we explore the potential for combining data from CryoSat-2, TanDEM-X, and ArcticDEM to document the evolution of four active subglacial lake sites in Greenland. The inclusion of the new data sources provides important information on lake activity, documenting that the ice surface collapse basin on Flade Isblink ice cap was 50 % (30 meters) deeper than previously recorded. We also present evidence of a new active subglacial lake in Southwest Greenland, which shows signs of being hydrologically connected to another subglacial lake in that region. These findings show how improving the measurement capabilities of subglacial lakes, improves our current understanding and knowledge of the subglacial water system and its connection to surface hydrology.

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Section: Subglacial Lake Volumessupporting

confidence: 64%

mentioning

confidence: 99%

Improved Monitoring of Subglacial Lake Activity in Greenland

Sørensen

Bahbah

Simonsen

et al. 2023

Preprint

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“…These results also suggest that shear heating must be accounted for as a contribution to subglacial lakes and may be a way to model the volume of water in subglacial lakes. Improving the modelling of the contribution of water to subglacial lakes may be a step towards predicting changes to flow speed due to floods from subglacial lakes [17,20,69]. Finally, the localization of meltwater delivery in shear margins has important implications for the spatial variability of basal shear stress and the patterns of subglacial channels underneath Antarctic ice streams.…”

Section: Discussionmentioning

confidence: 99%

Meltwater generation in ice stream shear margins: case study in Antarctic ice streams

et al. 2023

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Liquid water within glacier ice and at the glacier beds exerts a significant control on ice flow and glacier stability through a number of processes, including altering the rheology of the ice and lubricating the bed. Some of this water is generated as melt from regions of rapid deformation, including shear margins, due to heating by viscous dissipation. However, how much meltwater is generated and drained from shear margins remains unclear. Here, we apply a model that describes the evolution of ice temperature, melting, and water transport within deforming ice to estimate the flux of meltwater from shear margins in glaciers. We estimate the flux of meltwater from temperate ice zones in three Antarctic regions: Bindschadler and MacAyeal Ice Streams, Pine Island Glacier, and Byrd Glacier. We show that the flux of meltwater from shear margins in these regions may be as significant as the meltwater produced by frictional heating at the bed, with average fluxes of ∼ 0.005 – 0.1 m yr − 1 . This contribution of shear heating to meltwater flux at the bed may thus affect both the rheology of the ice as well as sliding at the bed, both key controls on fast ice flow.

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“…Space-borne altimetry has the capability to elucidate the connections between basal water flow, ice sheet stability, and marine mass exchange. It can also detect significant volume fluctuations in Antarctic subglacial lakes over decadal timescales, and it has also been used to investigate the correlations between these lakes [14,38,39]. The seismic method, dating back to the pioneering work of Robin (1958) [40], has been crucial in confirming subglacial lake presence, resolving uncertainties, and assessing subglacial water salinity.…”

Section: Subglacial Water Detection Methodsmentioning

confidence: 99%

The Antarctic Subglacial Hydrological Environment and International Drilling Projects: A Review

Zhou,

Cui,

Dai

et al. 2024

Water

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Subglacial lakes and hydrological systems play crucial roles in Antarctic subglacial hydrology, water balance, subglacial geomorphology, and ice dynamics. Satellite altimetry has revealed that some recurrent water exchange occurs in subglacial lakes. They are referred to as ’active lakes’, which prominently influence a majority of subglacial hydrological processes. Our analysis indicates that active subglacial lakes are more likely to be situated in regions with higher surface ice flow velocities. Nevertheless, the origin of subglacial lakes still remains enigmatic and uncertain. They could have potential associations with geothermal heat, ice sheets melting, and ice flow dynamics. Subglacial lake drilling and water sampling have the potential to provide valuable insights into the origin of subglacial lakes and subglacial hydrological processes. Moreover, they could also offer unique opportunities for the exploration of subglacial microbiology, evolution of the Antarctic ice sheets, and various fundamental scientific inquiries. To date, successful drilling and sampling has been accomplished in Lake Vostok, Lake Mercer, and Lake Whillans. However, the use of drilling fluids caused the water sample contamination in Lake Vostok, and the drilling attempt at Lake Ellsworth failed due to technical issues. To explore more of the conditions of the Antarctic subglacial lakes, the Lake Centro de Estudios Científicos (Lake CECs) and Lake Snow Eagle (LSE) drilling projects are upcoming and in preparation. In this study, we aim to address the following: (1) introduce various aspects of Antarctic subglacial lakes, subglacial hydrological elements, subglacial hydrology, and the interactions between ice sheets and the ocean; and (2) provide an overview and outlook of subglacial lakes drilling projects.

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Surface Expression and Apparent Timing of Subglacial Lake Oscillations Controlled by Viscous Ice Flow

Cited by 8 publications

References 53 publications

Improved Monitoring of Subglacial Lake Activity in Greenland

Improved Monitoring of Subglacial Lake Activity in Greenland

Meltwater generation in ice stream shear margins: case study in Antarctic ice streams

The Antarctic Subglacial Hydrological Environment and International Drilling Projects: A Review

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