Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia’s retreat in SW Greenland

Roman J. Motyka, Ryan Cassotto, Martin Truffer, Kristian Kjellerup Kjeldsen, Dirk van As, Niels J. Korsgaard, Mark Fahnestock, Ian Howat, Peter L. Langen, John Mortensen, Kunuk Lennert, Søren Rysgaard

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We assess ice loss and velocity changes between 1985 and 2014 of three tidewater and fivelandterminating glaciers in Godthåbsfjord (Nuup Kangerlua), Greenland. Glacier thinning accounted for43.8 ± 0.2 km3 of ice loss, equivalent to 0.10 mm eustatic sea-level rise. An additional 3.5 ± 0.3 km3 waslost to the calving retreats of Kangiata Nunaata Sermia (KNS) and Narsap Sermia (NS), two tidewaterglaciers that exhibited asynchronous behavior over the study period. KNS has retreated 22 km fromits Little Ice Age (LIA) maximum (1761 AD), of which 0.8 km since 1985. KNS has stabilized inshallow water, but seasonally advects a 2 km long floating tongue. In contrast, NS began retreatingfrom its LIA moraine in 2004–06 (0.6 km), re-stabilized, then retreated 3.3 km during 2010–14 intoan over-deepened basin. Velocities at KNS ranged 5–6 km a−1, while at NS they increased from 1.5 to5.5 km a−1 between 2004 and 2014. We present comprehensive analyses of glacier thinning, runoff,surface mass balance, ocean conditions, submarine melting, bed topography, ice mélange and concludethat the 2010–14 NS retreat was triggered by a combination of factors but primarily by an increase insubmarine melting.
Original languageEnglish
JournalJournal of Glaciology
Volume63
Pages (from-to)288-308
ISSN0022-1430
DOIs
Publication statusPublished - 2017
Externally publishedYes

Bibliographical note

© The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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