Quantifying Surface Changes on McMurdo Ice Shelf, Antarctica

• Main Author: Hill, Ann M.
• Format: Text
• Language: unknown
• Published: DigitalCommons@UMaine 2021
• Subjects: Earth Sciences; Glaciology; Antarctic; West Antarctica; Ross Island; Ross Ice Shelf; McMurdo Ice Shelf; Hut Point; Hut Point Peninsula; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://digitalcommons.library.umaine.edu/etd/3458; https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=4521&context=etd

The amount of ice stored in Antarctica has the potential to raise sea level by almost 60 meters. Mass is primarily lost through glaciers draining the ice sheet and flowing into and ice shelves. Ice shelves float on the ocean and act as a resisting force to the flow of the glaciers, thereby modulating the flow of tributary glaciers, and consequently glacier contribution to global sea level rise. McMurdo Ice Shelf (MIS) buttresses four tributary glaciers, three of which will be discussed in this thesis, as well as the northwest corner of the faster flowing Ross Ice Shelf, which has tributary glaciers flowing from both East and West Antarctica. McMurdo Ice Shelf also serves as a runway for planes traveling to research bases on Ross Island. Therefore, if MIS were to thin, become unstable, or collapse, the results would not only impact the rate of sea level rise, but also Antarctic science logistics. This thesis quantifies changes in surface elevation and surface velocity to better understand the relationship between MIS and its tributary glaciers. I isolated the surface elevation change resulting from accumulation and ablation, and tracked ice shelf retreat across the study region. I differenced high resolution digital elevation models (DEMs, 2011 – 2015) in the Hut Point region of Ross Island, first correcting for errors introduced in DEM processing, and then removing the tidal and atmospheric pressures across the ice shelf region. These results revealed variable elevation change across the ice shelf (± 2 m) and across the ice on Hut Point Peninsula (± 5 m) as well as ice shelf front retreat (up to 1 km). While both the ice shelf thinning and the frontal retreat contribute to the instability of MIS, the retreat is immediately concerning as it threatens to cut off Ross Island from the runways via Pegasus Road, thereby necessitating that a relocation of the road be considered. To further explore this system, I focused on evaluating velocity changes, and deriving strain rates across the glacier-ice shelf system on ...