Filtering by Subject: Glaciology

An interconnected palaeo-subglacial lake system in the central Barents Sea

Mariana Esteves, Denise Christina Rüther, Monica C.W. Winsborrow, et al.

Published: 2022-12-03
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology, Sedimentology

Drainage of meltwater beneath an ice sheet influences ice-flow dynamics. To better predict ice sheet behaviour, it is crucial to understand subglacial hydrological processes. Subglacial lakes are important components of the subglacial hydrological system, with many observed and predicted at the beds of contemporary and palaeo-ice sheets. The technical and logistical challenges of studying [...]

The highly nonlinear viscosity of fast-flowing glacier ice

Meghana Ranganathan, Brent Minchew

Published: 2022-12-01
Subjects: Glaciology

Glacier flow modulates sea level and is governed by the viscous deformation of ice. Multiple molecular-scale mechanisms facilitate viscous deformation, but it remains unclear how each contributes to glacier-scale deformation and how to represent them in ice-flow models. Here, we present a model of ice deformation that unifies existing estimates of the viscous parameters and provides a framework [...]

The effect of uncertainties in creep activation energies on modeling ice flow and deformation

Meghana Ranganathan, Brent Minchew

Published: 2022-11-21
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics

Ice deformation is commonly represented by a power-law constitutive relation, Glen's Flow Law, where deformation (strain) rate equals stress raised to the power n and multiplied by a flow-rate parameter A. Glen's Law represents bulk ice rheology as a single power-law even though multiple mechanisms, each with their own power-law relation and parametric values, act together during viscous [...]

Epitomic Data for Community Land Model Standalone Simulations for Prognostic Analyses of Tropical Mountain Glaciation and Lake Temperature in Pre-Industrial, Last Glacial Maximum, and Extreme Glacial Climates

Nicholas Gray Heavens

Published: 2022-11-15
Subjects: Climate, Fresh Water Studies, Glaciology, Hydrology

Global climate models typically simulate climate at much larger spatial scales than tropical mountain glaciers and many of the world’s lakes. Yet some of the proxy data that can be used to validate models of past climate on land come from and are related to these geographic features. Validating global climate models using these proxies requires some method of downscaling global climate model [...]

Revisiting earlier predictions of glacier retreat: The case of Langfjordjøkelen

Charalampos Charalampidis

Published: 2022-11-09
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

European glaciers constitute a part of the climate system that is bound to greatly change in the course of the 21st century. Recent length-change observations from Langfjordjøkelen in northern Norway confirm the earlier predictions of Charalampidis (2012), who identified the glacier’s disequilibrium with climate and hence extensive committed ice loss in the 21st century. Simulations suggest that, [...]

Remote sensing-derived time series of transient snowline altitudes for High Mountain Asia, 1986–2021

David Loibl, Niklas Richter, Inge Grünberg

Published: 2022-10-24
Subjects: Earth Sciences, Glaciology

This study presents a new dataset of remote sensing-derived Transient Snowline Altitude (TSLA) measurements for glaciers in High Mountain Asia. We use the Google Earth Engine to obtain TSLA data for approx. 28 · 104 glaciers larger than 0.5 km². After filtering and postprocessing, the dataset comprises ca. 9.66 million TSLA measurements with an average of 341 ± 160 measurements per glacier, [...]

The impact of Holocene deglaciation and glacial dynamics on the landscapes and geomorphology of Potter Peninsula, King George Island (Isla 25 Mayo), NW Antarctic Peninsula

Pablo Heredia Barión, Jorge A Strelin, Stephen J Roberts, et al.

Published: 2022-10-19
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology, Physical Sciences and Mathematics, Sedimentology

The timing and impact of deglaciation and Holocene readvances on many ice-free terrestrial continental margins of the Antarctic Peninsula have been long-studied but remain debated. Potter Peninsula on King George Island (Isla 25 de Mayo), South Shetland Islands (SSI), NW Antarctic Peninsula has a detailed assemblage of glacial landforms, geomorphological features and stratigraphic exposures for [...]

Distributed Acoustic Sensing in a Greenlandic Outlet Glacier: Developing Machine Learning Approaches to Benefit Cryoseismic Data Analysis

Adam Booth, Poul Christoffersen, Andrew Pretorius, et al.

Published: 2022-10-08
Subjects: Geophysics and Seismology, Glaciology, Other Computer Sciences

The recognition of Distributed Acoustic Sensing (DAS) as a valuable tool for glaciological seismic applications is growing. However, besides the logistical challenges of installing fibre-optic cable, the volume of DAS data that can be collected in a field campaign poses computational challenges. In this paper, we show the potential of active-source DAS to image and characterise subglacial [...]

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

Ice discharge from Greenland’s marine-terminating glaciers contributes to half of all mass loss from the ice sheet, with numerous mechanisms proposed to explain their retreat. Here, we examine K.I.V Steenstrups Nordre Bræ (‘Steenstrup’) in Southeast Greenland, which, between 2018—2021, retreated ~7 km, thinned ~20%, doubled in discharge, and quadrupled in flow speed. This rate of acceleration is [...]

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) [...]


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