Small glacier changes over the past 60+ years on Axel Heiberg Island, Nunavut, Canada, using Structure from Motion
Abstract
There has been a marked increase in melt season length over the past two decades on glaciers and ice caps within Canada's Queen Elizabeth Islands (QEI). Prior to the year ~2000 (1958-1995) land ice was in a state of slightly negative mass balance (-11.9 ± 11.5 Gt yr-1), but recent GRACE measurements suggest that losses between 2003 and 2015 averaged -33 ± 5 Gt yr-1. This increase in meltwater runoff has made the QEI one of the largest recent contributors to sea level rise outside of the ice sheets, with the capacity to raise sea level by ~109 mm. Despite these losses, there is a paucity of information concerning how a warming climate is affecting small (<1 km2) ice bodies, which are likely sensitive indicators of climate change due to their short response time.
In this study, we describe the use of historical and contemporary aerial photographs, high-resolution optical satellite imagery, and ground penetrating radar (GPR) surveys to determine the area and volume changes of Baby, Trent, and Black Crown glaciers within Expedition Fiord (Axel Heiberg Island) over the past six decades. Historical (1959) and contemporary (2019) digital elevation models (DEMs) were created via aerial photo surveys using Structure from Motion photogrammetry. The DEMs were accurately co-registered by combining direct measurements of camera positions using a dual-frequency GPS system and multiple ground control points situated around the study region. Volume changes derived from DEM differencing were validated using 36 years of in-situ mass balance measurements from Baby Glacier collected intermittently between 1959 and 2019, together with 2014 and 2019 GPR surveys. The results from this study indicate that small ice masses are rapidly declining within the QEI, and support future projections of the life expectancy of these small ice bodies.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C31B1513S
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0762 Mass balance;
- CRYOSPHERE;
- 0776 Glaciology;
- CRYOSPHERE