Using Archived Aerial Photography to Measure Long-term Change in the Surface Elevation of Larsen A Tributary Glaciers from 1957 to 2020

Glacial ice loss is a key indicator of Atmospheric Warming (AW). Ice mass loss from the Antarctic Peninsula (AP) accounted for approximately 17% of the total Antarctic losses between 2009 and 2017 (Rignot et al., 2019). Ice mass loss contributes to increases in local sea levels and since the 1960’s, losses from the AP and surrounding areas have contributed approximately 30% to cryosphere driven Sea Level Rise (SLR) (Hock et al., 2009). Therefore, monitoring ice loss in this region is key to improving our understanding of glaciological behaviour and responses to AW. The rate of AP ice mass loss significantly increased from 8 ± 17 Gt yr-1 in 1992 to 36 ± 10 Gt yr-1 in 2010 (Shepherd et al., 2012). At the start of this period, 87% of outlet glaciers on the AP showed signs of retreat (Ferringo et al., 2008). It is surmised that ice shelf collapse is the dominant process by which ice mass is lost in this region (Royston and Gudmundsson, 2016). Therefore, glaciological behaviour prior to and following ice shelf collapse will inform of the local impact on ice mass. One ice shelf on the AP, the Larsen A (LAIS) collapsed in 1995, resulting in the thinning and acceleration of its tributary glaciers. Ice loss from LAIS tributaries between 2009 and 2017, accounted for approximately 18% of what was lost from the Northern AP (Scambos et al., 2014). Historically, (pre-1990s) changes in the surface elevation of glaciers have been observed but not accurately measured due to lack of pre-satellite altimetry data and reliable Ground Control Points (GCPs). This study presents the results of existing methodology for building geographically accurate DEMs from archived aerial photographs obtained in 1957 and 1995, where in situ GCPs are limited or non-existent. Historic DEMs were used alongside the REMA DEM to measure change in ice elevation, pre and post the collapse of the LAIS. It was determined that glacial response in the decades prior to and following the collapse of the LAIS was not uniform and may be dependent upon their specific topography and resultant glacial morphology. In addition, this study describes a cost-efficient methodology to build DEMs that could be used for initial investigations and to justify further resource investment.

Level dc:type.qualificationlevel

Masters

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2024

Author dc:creator

• Rowe, Evangeline

Advisor dc:contributor.advisor

• Willis, Ian

Licence

• http://purl.org/NET/rdflicense/allrightsreserved

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.115387

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/379224