Title: Triggers Of Rapid Change In Glacier Dynamics
Program: Doctor of Philosophy in Geophysics
Advisor: Dr. Ellyn Enderlin, Geosciences
Committee Members: Dr. Dylan Mikesell, College of Arts and Sciences; Dr. Hans-Peter Marshall, Geosciences; and Dr. Christine Dow, Geosciences
The dynamics of the glaciers that drain the Greenland and Antarctic ice sheets dominate their present and future ice mass loss, which impacts sea level, global ocean circulation, and inputs to local ecosystems. Global glacier models still do not adequately represent the processes that govern development of instabilities from perturbations at the ice-rock and ice-ocean interfaces (glacier bed and terminus, respectively) due to knowledge gaps that arise, in part, from the difficulty of observing changes at these interfaces directly. For my dissertation, I developed automated methods for processing large remote sensing datasets to observe changes in glacier dynamics (i.e., glacier length, speed, and thickness) at finer spatial and temporal scales. I use satellite image feature-tracking and edge detection algorithms to investigate case studies of glacier terminus retreat and surges (cyclical, order-of-magnitude glacier speedups) in Greenland and Alaska. Analysis of the resulting datasets along with environmental variables reveal additional complexity in the interplay of external (environmental) and internal factors that influence glacier dynamics at sub-seasonal to annual timescales. These findings contribute to our understanding of the formation and progression of ice instabilities that trigger rapid changes in glacier dynamics.