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Articles 1 - 5 of 5
Full-Text Articles in Glaciology
A Non-Deterministic Deep Learning Based Surrogate For Ice Sheet Modeling, Hannah Jordan
A Non-Deterministic Deep Learning Based Surrogate For Ice Sheet Modeling, Hannah Jordan
Graduate Student Theses, Dissertations, & Professional Papers
Surrogate modeling is a new and expanding field in the world of deep learning, providing a computationally inexpensive way to approximate results from computationally demanding high-fidelity simulations. Ice sheet modeling is one of these computationally expensive models, the model used in this study currently requires between 10 and 20 minutes to complete one simulation. While this process is adequate for certain applications, the ability to use sampling approaches to perform statistical inference becomes infeasible. This issue can be overcome by using a surrogate model to approximate the ice sheet model, bringing the time to produce output down to a tenth …
Migration Of The Frozen/Melted Basal Boundary Linked To ~100 Kilometers Of Ice Margin Retreat, Western Greenland Ice Sheet, Aidan Ripley Stansberry
Migration Of The Frozen/Melted Basal Boundary Linked To ~100 Kilometers Of Ice Margin Retreat, Western Greenland Ice Sheet, Aidan Ripley Stansberry
Graduate Student Theses, Dissertations, & Professional Papers
The geometry and thermal structure of western Greenland ice sheet have evolved over the last 11 kyr in response to Holocene climate. Evolution of the frozen and melted fractions of the bed associated with the ice sheet retreat over this time frame remains unclear. We address this question using a thermo-mechanically coupled flowline model to simulate a 11 kyr period of ice sheet retreat in west central Greenland. Our transient flow-line modeling includes high order stresses, thermally active bedrock, a well-informed climate that is constrained by an established record of ice margin retreat. We partition the transient heat balance into …
Inference Of Surface Velocities From Oblique Time Lapse Photos And Terrestrial Based Lidar At The Helheim Glacier, Franklyn T. Dunbar Ii
Inference Of Surface Velocities From Oblique Time Lapse Photos And Terrestrial Based Lidar At The Helheim Glacier, Franklyn T. Dunbar Ii
Graduate Student Theses, Dissertations, & Professional Papers
Using time dependent observations derived from terrestrial LiDAR and oblique
time-lapse imagery, we demonstrate that a Bayesian approach to glacial motion es-
timation provides a concise way to incorporate multiple data products into a single
motion estimation procedure effectively producing surface velocity estimates with
an associated uncertainty. This approach brings both improved computational effi-
ciency, and greater scalability across observational time-frames when compared to
existing methods. To gauge efficacy, we apply these methods to a set of observa-
tions from the Helheim Glacier, a critical actor in contemporary mass loss trends
observed in the Greenland Ice Sheet. We find that …
Ice Flow Impacts The Firn Structure Of Greenland's Percolation Zone, Rosemary C. Leone
Ice Flow Impacts The Firn Structure Of Greenland's Percolation Zone, Rosemary C. Leone
Graduate Student Theses, Dissertations, & Professional Papers
One dimensional simulations of firn evolution neglect horizontal transport as the firn column moves down slope during burial. This approach is justifiable near Greenland's ice divide, where ice flow is near vertical, but fidelity is lost in the percolation zone where horizontal ice flow advects the firn column through climate gradients. We simulate firn evolution processes under advection conditions using a transient, thermo-mechanically coupled model for firn densification and heat transfer with various schemes for meltwater penetration and refreezing. The simulations isolate processes in synthetic runs and investigate an ice core site and four transects of Greenland’s percolation zone. The …
Temporal Evolution Of Basal Water Pressure And Ice Velocity Along A 50 Km Flow Line Transect Of Western Greenland, Patrick Wright
Temporal Evolution Of Basal Water Pressure And Ice Velocity Along A 50 Km Flow Line Transect Of Western Greenland, Patrick Wright
Graduate Student Theses, Dissertations, & Professional Papers
The gradient in hydraulic potential at the ice-bedrock interface beneath the Greenland Ice Sheet (GrIS) dictates the routing and energetics of subglacial water, thereby influencing drainage system characteristics and sliding dynamics. In the ablation zone of the GrIS, a high relief bed and gradients in water pressure in an active subglacial drainage system potentially play a complex role in dictating the hydraulic potential field. Here we present a suite of water pressure measurements collected within thirteen boreholes along a 46 km transect on the western GrIS in order to investigate the sensitivity of the potential gradient field to seasonal evolution …