Analysis of Terminus Position and Large Calving Events on 4 Greenland Tidewater Glaciers from 2001-2017
Abstract
Rising ocean levels are a major concern with respect to long-term climate change as ice sheets melt at record speeds. An important component contributing to mass loss is the calving of icebergs, but this process is poorly understood due to the interplay of several factors in a glacier's system. We observed Rink Isbrae, Kangerlussuaq Glacier, Jakobshavn Isbrae, and Helheim Glacier - the largest and fastest marine-terminating glaciers in Greenland - and examined the relationships between surface fractures, terminus variability, outside forcings, and their influence on large calving events. ASTER images were obtained through Earthdata to study their rapid speed ups in the 2000s, production of several high magnitude icebergs, and a known large tsunami event near Rink Isbrae in 2017. We used QGIS to trace fracture patterns and distribution of other prominent features before, during, and after events when data was available. We mapped the terminus position each year, as well as before and after large calving events, and a MATLAB code was used to output fracture count maps. Fracture maps generally showed that when terminus position was near its maximum forward position within the fjord, the floating portion of the glacier tongue was more heavily fractured. Helheim Glacier and Rink Isbrae fluctuated around a set position year-to-year rather than steadily receding, but all four glaciers exhibited a net retreat from 2001-2017 with major events contributing to the general trend in recession. In particular, a 2017 tsunami event triggered by a massive landslide in Karrat Fjord adjacent to Rink Isbrae is correlated with the rapid disintegration of the floating tongue within ten days of the event through the ejection of a 1.2km2 iceberg (Planet Team 2017; https://api.planet.com). Studying large calving events for these four glacier may ultimately contribute to more accurate predictions of the implications of global warming on the Greenland ice sheet and further sea level rise.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P21E3396W
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHEREDE: 4599 General or miscellaneous;
- OCEANOGRAPHY: PHYSICALDE: 6207 Comparative planetology;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6299 General or miscellaneous;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS