INVESTIGATING DYNAMIC GLACIER PROCESSES, MASS LOSS, AND COUPLED INTERACTIONS WITH THE SOLID EARTH USING SATELLITE GEODESY

• Main Author: Durkin, William Joseph
• Other Authors: Pritchard, Matthew, Cathles, Lawrence M., Silberstein, Meredith
• Format: Thesis
• Language: English
• Published: 2019
• Subjects: Antarctic; Greenland; Antarc*; glacier; glaciers; Iceland; Tidewater; Alaska
• Online Access: https://hdl.handle.net/1813/70017; http://dissertations.umi.com/cornellgrad:11760; https://doi.org/10.7298/tt6c-hk66

196 pages Glaciers outside of the Greenland and Antarctic ice sheets currently comprise ~1/3 of the cryosphere’s contribution to sea level rise (SLR) and are expected to remain a significant contributor during the 21st century. Glaciers represent vast reservoirs of fresh water, and their melt waters are often an important component of hydropower and agriculture for communities living in glacierized watersheds. In addition to surface melt, glaciers that terminate in the ocean (i.e., marine terminating or tidewater glaciers) can rapidly retreat and discharge large amounts ice from upper regions into the ocean. These processes are largely decoupled from climate and represent a major source of uncertainty in SLR projections. As glaciers redistribute their mass through ice discharge and melting, they evoke a deformational response of the solid Earth that can be used to better understand these processes or, conversely, probe the mechanical properties of the Earth’s interior. In this thesis, I use a variety of geodetic data and numerical models to quantify the changes to the cryosphere and the response of the sold Earth in Alaska and Iceland. I begin by investigating the processes promoting the advance of the marine terminating Yahtse Glacier in southern Alaska. Using the pixel tracking technique with satellite imagery, I construct a time series of the glacier’s velocity spanning the years 1985 – 2016. Rates of ice elevation change during years 2000 – 2014 are estimated from a time series of satellite-derived digital elevation maps (DEMs) by fitting a trend to the elevations on a pixel-by-pixel basis. We find that the development of a submarine shoal stabilizes the glacier’s terminus, causing the terminus to compressively thicken by ~6 m/yr and decelerate by ~45%. A steep (up to 35% slope) icefall prevents these stabilities from reaching the majority of the glacier. The continued influx of ice to an increasingly stable terminus promotes the glacier’s advance and highlights the important role of geometric controls in ...