Filtering by Subject: Glaciology

Seasonal flow types of glaciers in Sermilik Fjord, Greenland, over 2016–2021

Kristin Poinar

Published: 2022-09-08
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Greenland glaciers have three primary seasonal ice flow patterns, or “types”: terminus driven, runoff driven, and runoff adapting. To date, glacier types have been identified by analyzing flow at a single location near the terminus; information at all other locations is discarded. Here, we use principal component (PC) / empirical orthogonal function (EOF) analysis to decompose multi-year time [...]

Variational inference of ice shelf rheology with physics-informed machine learning

Bryan Riel, Brent Minchew

Published: 2022-09-06
Subjects: Earth Sciences, Glaciology, Other Mathematics, Other Statistics and Probability, Physical Sciences and Mathematics

Floating ice shelves that fringe the coast of Antarctica resist the flow of grounded ice into the ocean. One of the key factors governing the amount of flow-resistance provided by an ice shelf is the rigidity of the ice that constitutes it. Ice rigidity is highly heterogeneous and must be calibrated from spatially-continuous surface observations assimilated into an ice flow model. Moreover, [...]

Ocean Surface Gravity Wave Excitation of Flexural Gravity and Extensional Lamb Waves in Ice Shelves

Lauren S Abrahams, Jose E. Mierzejewski, Eric M Dunham

Published: 2022-08-30
Subjects: Earth Sciences, Glaciology, Numerical Analysis and Scientific Computing

Flexure and extension of ice shelves in response to incident ocean surface gravity waves have been linked to iceberg calving, rift growth, and even disintegration of ice shelves. Most modeling studies utilize a plate bending model for the ice, focusing exclusively on flexural gravity waves. Ross Ice shelf seismic data shows not only flexural gravity waves, with dominantly vertical displacements, [...]

Atlantic Water intrusion triggers rapid retreat and regime change at previously stable Greenland glacier

Thomas R Chudley, Ian M Howat, Michalea D King, et al.

Published: 2022-08-04
Subjects: Earth Sciences, Glaciology

Discharge from Greenland’s marine-terminating glaciers contribute to half of all mass loss from the ice sheet, but the factors forcing their retreat are complex and contested. Here, we examine K.I.V Steenstrups Nordre Bræ (‘Steenstrup’), which, between 2018—2021, retreated ~7 km, thinned by ~20%, doubled in ice discharge, and quadrupled in flow speed. This rate of acceleration is unprecedented [...]

Ascent rates of 3D fractures driven by a finite batch of buoyant fluid

Timothy Davis, Eleonora Rivalta, Delphine Smittarello, et al.

Published: 2022-06-20
Subjects: Fluid Dynamics, Geology, Glaciology, Mechanics of Materials, Volcanology

Propagation of fluid-filled fractures by fluid buoyancy is important in a variety of settings, from magmatic dykes and veins to water-filled crevasses in glaciers. Industrial hydro-fracturing utilises fluid-driven fractures to increase the permeability of rock formations; the effect of buoyancy on fracture pathways in this context is typically neglected. Analytical approximations for the buoyant [...]

Surging vs. streaming: the dual fast ice flow response to variations in efficiency of the subglacial drainage landsystem

Ravier Edouard, Thomas Lelandais, Jean Vérité, et al.

Published: 2022-05-24
Subjects: Geomorphology, Glaciology

Observation and modelling have long contributed to associate surging and streaming of glaciers with glacier thermal regime, variations in meltwater availability and pressure and mechanical coupling at their beds. Using experimental modelling and palaeoglaciological mapping, we explore how the development of subglacial drainage landsystems controls variations in drainage efficiency and ice flow [...]

Complex motion of Greenland Ice Sheet outlet glaciers with basal temperate ice

Robert Law, Poul Christoffersen, Emma MacKie, et al.

Published: 2022-05-19
Subjects: Glaciology

Uncertainty associated with ice motion plagues sea-level rise predictions. Much of this uncertainty arises from imperfect representations of physical processes including basal slip and internal ice deformation, with ice-sheet models largely incapable of reproducing borehole-based observations. To investigate further, we model isolated 3D domains from fast-moving (Sermeq Kujalleq or Store Glacier) [...]

The CREp 36Cl exposure age calculator: development version “dev”

Irene Schimmelpfennig, Pierre-Henri BLARD, Jim Tesson, et al.

Published: 2022-05-04
Subjects: Geochemistry, Geology, Geomorphology, Glaciology, Sedimentology, Tectonics and Structure, Volcanology

Chlorine-36 (36Cl) is currently the only in situ cosmogenic nuclide applicable in carbonates, Ca- and K-rich feldspars and aphyric silicate rocks. Because the production reactions of 36Cl are more numerous and complex than those of other cosmogenic nuclides (e.g. 10Be, 3He), comprehensive and user-friendly calculators are essential for routine application of 36Cl to Earth surface research [...]

Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia

Stephen J Roberts, Robert D McCulloch, Joseph F Emmings, et al.

Published: 2022-03-29
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Glaciology, Hydrology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology

We undertook multiproxy analyses on two sediment cores from Lago Pato, a small lake basin at 51°S topographically separated from Lago del Toro in Torres del Paine (TdP), to provide insights into glacier dynamics and lake level change in the TdP and Última Esperanza region over the last ~30,000 cal a BP (30 ka). Lago Pato is situated in a region overridden by the Southern Patagonian Icefield [...]

Decoupling between strain localisation and the microstructural record: evidence from in-situ strain measurements in polycrystalline ice

Marco Antonio Lopez-Sanchez, Thomas Chauve, Maurine Montagnat, et al.

Published: 2022-03-28
Subjects: Earth Sciences, Glaciology, Tectonics and Structure

We explore the links between strain localization and the evolution of the microstructure in crystalline materials deforming by dislocation creep. Using digital image correlation (DIC), we monitored the evolution of the strain field in two coarse-grained columnar Ih ice samples deformed by creep (uniaxial compression at constant load) at 7º C and 0.5 MPa up to 9.5% bulk shortening. After a brief [...]

Greenland ice sheet vulnerability under diverse climatic warming scenarios

Benjamin Andrew Keisling, Joerg M. Schaefer, Robert DeConto, et al.

Published: 2022-03-26
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Sea-level rise of even one meter will have drastic global impacts. Melting the Greenland Ice Sheet (GIS) would raise sea level by 7.4 meters. There is an urgent need to improve predictions of how quickly the GIS will contribute its first meter of sea-level rise, and from where on the ice sheet that water will come. Estimating the volume of Greenland ice that was lost during past warm periods [...]

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

Meghana Ranganathan, Jack-William Barotta, Colin R. Meyer, et al.

Published: 2022-01-05
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

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 in regions of rapid deformation, including shear margins, due to heating by viscous dissipation. However, how much meltwater is generated and [...]

Streamlined subglacial bedform sensitivity to bed characteristics across the deglaciated Northern Hemisphere

Marion A. McKenzie, Lauren Miller Simkins, Sarah Principato

Published: 2021-11-10
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology

Streamlined subglacial bedforms observed in deglaciated landscapes provide the opportunity to assess the sensitivity of glacier dynamics to bed characteristics across broader spatiotemporal scales than is possible for contemporary glacial systems. While many studies of streamlined subglacial bedforms rely on manual mapping and qualitative (i.e., visual) assessment, we semi-automatically identify [...]

Persistent shallow micro-seismicity at Llaima volcano, Chile, with implications for long-term monitoring

Oliver Lamb, Jonathan M Lees, Luis Franco Marin, et al.

Published: 2021-11-01
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics, Volcanology

Identifying the source mechanisms of low-frequency earthquakes at ice-covered volcanoes can be challenging due to overlapping characteristics of glacially and magmatically derived seismicity. Here we present an analysis of two months of seismic data from Llaima volcano, Chile, recorded by the permanent monitoring network in 2019. We find over 2,000 repeating low-frequency events split across 82 [...]

Reproducibility in subsurface geoscience

Michael J. Steventon, Christopher Aiden-Lee Jackson, Mark Ireland, et al.

Published: 2021-10-26
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Paleobiology, Paleontology, Sedimentology, Soil Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management

Reproducibility, the extent to which consistent results are obtained when an experiment or study is repeated, sits at the foundation of science. The aim of this process is to produce robust findings and knowledge, with reproducibility being the screening tool to benchmark how well we are implementing the scientific method. However, the re-examination of results from many disciplines has caused [...]


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