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Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland

Joughin, Ian and Howat, Ian and Alley, Richard B. and Ekstrom, Goran and Fahnestock, Mark and Moon, Twila and Nettles, Meredith and Truffer, Martin and Tsai, Victor C. (2008) Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland. Journal of Geophysical Research F, 113 (F1). Art. No. F01004 . ISSN 0148-0227. doi:10.1029/2007JF000837.

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We used satellite images to examine the calving behavior of Helheim and Kangerdlugssuaq Glaciers, Greenland, from 2001 to 2006, a period in which they retreated and sped up. These data show that many large iceberg-calving episodes coincided with teleseismically detected glacial earthquakes, suggesting that calving-related processes are the source of the seismicity. For each of several events for which we have observations, the ice front calved back to a large, pre-existing rift. These rifts form where the ice has thinned to near flotation as the ice front retreats down the back side of a bathymetric high, which agrees well with earlier theoretical predictions. In addition to the recent retreat in a period of higher temperatures, analysis of several images shows that Helheim retreated in the 20th Century during a warmer period and then re-advanced during a subsequent cooler period. This apparent sensitivity to warming suggests that higher temperatures may promote an initial retreat off a bathymetric high that is then sustained by tidewater dynamics as the ice front retreats into deeper water. The cycle of frontal advance and retreat in less than a century indicates that tidewater glaciers in Greenland can advance rapidly. Greenland's larger reservoir of inland ice and conditions that favor the formation of ice shelves likely contribute to the rapid rates of advance.

Item Type:Article
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Tsai, Victor C.0000-0003-1809-6672
Additional Information:© 2008 by the American Geophysical Union. Received 23 May 2007; accepted 23 October 2007; published 26 January 2008. The National Science Foundation (NSF) supported contributions by I. Joughin, T. Moon, and R. Alley, M. Fahnestock, and M. Truffer through Arctic System Science Grants: ARC0531270, ARC0531211, ARC 0531250 and ARC0531075. The National Aerospace Administration supported I. Howat’s contribution (NNG06GE5SG) and an NSF Graduate Research Fellowship supported V. Tsai. Comments by T. Murray, A. Vieli, and S. O’Neel led to improvements in the final manuscript.
Group:Seismological Laboratory
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:F1
Record Number:CaltechAUTHORS:20140618-143619582
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Official Citation:Joughin, I., I. Howat, R. B. Alley, G. Ekstrom, M. Fahnestock, T. Moon, M. Nettles, M. Truffer, and V. C. Tsai (2008), Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland, J. Geophys. Res., 113, F01004, doi:10.1029/2007JF000837
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46344
Deposited By: Tony Diaz
Deposited On:18 Jun 2014 21:46
Last Modified:10 Nov 2021 17:24

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