Preprints
Filtering by Subject: Glaciology
Glacier projections sensitivity to temperature-index model choices and calibration strategies
Published: 2023-03-03
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
Published: 2023-02-23
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
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
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
Published: 2022-12-16
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
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
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
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
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
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
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
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 the terrestrial continental margins of the Antarctic Peninsula have been well-studied but are still 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 and stratigraphic exposures for constraining deglacial landscape [...]
Distributed Acoustic Sensing in a Greenlandic Outlet Glacier: Developing Machine Learning Approaches to Benefit Cryoseismic Data Analysis
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
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
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, [...]