Filtering by Subject: Glaciology

The role of thermal notch erosion in forcing localised calving failure and short-term increases in velocity at a lake-terminating glacier in southeast Iceland

Nathaniel Ross Baurley, Jane K Hart

Published: 2023-05-25
Subjects: Glaciology

We utilised repeat high-resolution UAV-SfM surveys, alongside terrestrial photography acquired in-situ, to investigate, for the first time, the role of thermal notch erosion in forcing localised calving failure and subsequent short-term increases in velocity at a lake-terminating glacier. This data was acquired daily (where possible) across one week in July 2019 and two weeks in July 2021 to [...]

Harmonizing GCW Cryosphere Vocabularies with ENVO and SWEET: Towards a General Model for Semantic Harmonization

Ruth Duerr, Pier Luigi Buttigieg, Gary Berg-Cross, et al.

Published: 2023-05-17
Subjects: Databases and Information Systems, Geomorphology, Glaciology, Other Earth Sciences

This paper presents the specific process we, as part of the Earth Science Information Partners (ESIP) Semantic Harmonization Cluster, used to harmonize terms from the Global Cryosphere Watch (GCW) compilation of cryospheric terms with the Semantic Web for Earth and Environmental Terminology (SWEET) and the Environment Ontology (ENVO). In addition, we summarize a number of leading practices which [...]

Different mechanisms of Arctic first-year sea-ice ridge consolidation observed during the MOSAiC expedition

Evgenii Salganik, Benjamin Allen Lange, Polona Itkin, et al.

Published: 2023-05-10
Subjects: Earth Sciences, Glaciology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Sea-ice ridges constitute a large fraction of the ice volume in the Arctic Ocean, yet we know little about the evolution of these ice masses. Here we examine the thermal and morphological evolution of an Arctic first-year sea-ice ridge, from its formation to advanced melt. Initially the mean keel depth was 5.6 m and mean sail height was 0.7 m. The initial rubble macroporosity (fraction of [...]

Ice flow model emulator based on physics-informed deep learning

Guillaume Jouvet, Guillaume Cordonnier

Published: 2023-05-08
Subjects: Glaciology

Convolutional Neural Networks trained from physical high-order ice flow model realizations have proven to be outstanding emulators in terms of computational-to-fidelity performance. However, the dependence on an ensemble of realizations of an instructor model renders this strategy difficult to generalize to the variety of glacier shape and ice flow that can be met in nature. To overcome this [...]

Linear analysis of ice-shelf topography response to basal melting and freezing

Aaron Grey Stubblefield, Colin R. Meyer, Martin Wearing

Published: 2023-04-29
Subjects: Applied Mathematics, Dynamic Systems, Earth Sciences, Fluid Dynamics, Glaciology, Physical Sciences and Mathematics, Physics

Floating ice shelves in Antarctica and Greenland limit land-ice contributions to sea level rise by resisting the flow of grounded ice. Melting at the surface and base of ice shelves can lead to destabilisation by promoting thinning and fracturing. Basal melting often results in channelised features that manifest as surface topography due to buoyancy. The assumption of hydrostatic flotation [...]

Assessing multi-hazard susceptibility to cryospheric hazards: lesson learnt from an Alaskan example

Letizia Elia, Silvia Castellaro, Ashok Dahal, et al.

Published: 2023-04-28
Subjects: Applied Statistics, Geomorphology, Glaciology, Statistical Models

Classifying a given landscape on the basis of its susceptibility to surface processes is a standard procedure in low to mid-latitudes. Conversely, these procedures have hardly been explored in periglacial regions, primarily because of the limited presence of human settlements and, therefore, the little need for risk assessment. However, global warming is radically changing this situation and [...]

Reconstructing subglacial lake activity with an altimetry-based inverse method

Aaron Grey Stubblefield, Colin R. Meyer, Matthew Siegfried, et al.

Published: 2023-04-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Subglacial lake water-volume changes produce ice-elevation anomalies that provide clues about water flow beneath glaciers and ice sheets. Significant challenges remain in the quantitative interpretation of these elevation-change anomalies because the surface expression of subglacial lake activity depends on basal conditions, rate of water-volume change, and ice rheology. To address these [...]

A shallow approximation for ice streams sliding over strong beds

Katarzyna L P Warburton, Duncan Hewitt, Colin R. Meyer, et al.

Published: 2023-03-29
Subjects: Glaciology, Partial Differential Equations

Ice streams are regions of rapid ice sheet flow characterised by a high degree of sliding over a deforming bed. The Shallow Shelf Approximation (SSA) provides a convenient way to obtain closed-form approximations of the velocity and flux in a rapidly-sliding ice stream when the basal drag is much less than the driving stress. However, the validity of the SSA approximation breaks down when the [...]

A method for the measurement of seismic attenuation in polar firn

Ronan Samuel Agnew, Roger Clark, Adam Booth, et al.

Published: 2023-03-04
Subjects: Geophysics and Seismology, Glaciology

We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional- and shear-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor (Q) based on analysis of diving waves, which enables us to characterise the attenuative structure of firn in greater detail than has previously [...]

Glacier projections sensitivity to temperature-index model choices and calibration strategies

Lilian Schuster, David Robert Rounce, Fabien Maussion

Published: 2023-03-04
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Glacier models contribute significantly to the uncertainty of glacier change projections. In this study, we focus on temperature-index mass-balance (MB) models and their calibration, exploring the impact of various design choices on projections. Using the Open Global Glacier Model (OGGM), we compare the effects of different surface-type dependent degree-day factors, temporal climate resolutions [...]

Detection and Characterization of Discontinuous Motion on Thompson Glacier, Canadian High Arctic, Using Synthetic Aperture Radar Speckle Tracking and Ice-Flow Modeling

Giovanni Corti, Bernhard Rabus, Gwenn Elizabeth Flowers

Published: 2023-02-24
Subjects: Glaciology

We investigate unusual discontinuous glacier motion on Thompson Glacier, Umingmat Nunaat, Arctic Canada, using synthetic aperture radar (SAR) images and ice-flow modeling. A novel intensity-rescaling scheme is developed to reduce errors in high resolution speckle tracking, resulting in a ~25% improvement in accuracy. Interferometric SAR (InSAR) and speckle tracking using high resolution [...]

Simulating the processes controlling ice-shelf rift paths using damage mechanics

Alex Huth, Ravindra Duddu, Benjamin Smith, et al.

Published: 2023-02-21
Subjects: Glaciology

Rifts are full-thickness fractures that propagate laterally across the ice shelf. They cause ice-shelf weakening and calving of tabular icebergs, and control the initial size of calved icebergs. Here, we present a combined inverse and forward computational modeling framework to capture rifting by combining the vertically integrated momentum balance and anisotropic continuum damage mechanics [...]

Temporal evolution of under-ice meltwater layers and false bottoms and their impact on summer Arctic sea ice mass balance

Evgenii Salganik, Christian Katlein, Benjamin Allen Lange, et al.

Published: 2023-02-16
Subjects: Earth Sciences, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Low-salinity meltwater from Arctic sea ice and its snow cover accumulates and creates under-ice meltwater layers below sea ice. These meltwater layers can result in the formation of new ice layers, or false bottoms, at the interface of this low-salinity meltwater and colder seawater. As part of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC), we used a [...]

Evolution of the seasonal dynamics of the lake-terminating glacier Fjallsjökull, southeast Iceland, inferred using high-resolution repeat UAV imagery

Nathaniel Ross Baurley, Jane K Hart

Published: 2022-12-17
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Proglacial lakes are becoming ubiquitous at the termini of many glaciers worldwide, leading to increased glacier mass loss and terminus retreat, yet an understanding of the key processes forcing their behaviour is lacking. This study utilised high-resolution repeat uncrewed aerial vehicle (UAV)-Structure from Motion (SfM) imagery to provide insights into the changing dynamics of Fjallsjökull, a [...]

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 [...]


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