Filtering by Subject: Glaciology
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]
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 [...]