Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/tc-2018-17
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
09 Feb 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal The Cryosphere (TC).
Dynamic changes in outlet glaciers in northern Greenland from 1948 to 2015
Emily A. Hill1, J. Rachel Carr1, Chris R. Stokes2, and G. Hilmar Gudmundsson3 1School of Geography, Politics, and Sociology, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK
2Department of Geography, Durham University, Durham, DH1 3TQ, UK
3Department of Geography and Environmental Sciences, Northumbria University, Newcastle-upon-Tyne, NE1 8ST, UK
Abstract. The Greenland Ice Sheet (GrIS) is losing mass in response to recent climatic and oceanic warming. Since the mid-1990s, marine-terminating outlet glaciers across the GrIS have retreated, accelerated and thinned, but recent changes in northern Greenland have been comparatively understudied. Consequently, the dynamic response (i.e. changes in surface elevation and velocity) of these outlet glaciers to changes at their termini, particularly calving from floating ice tongues, remains unknown. Here we use satellite imagery and historical maps to produce an unprecedented 68-year record of terminus change across 18 major outlet glaciers and combine this with previously published surface elevation and velocity datasets. Overall, recent (1995–2015) retreat rates were higher than at any time in the previous 47 years, but change-point analysis reveals three categories of frontal position change: (i) minimal change followed by steady and continuous retreat, (ii) minimal change followed by a switch to a period of short-lived rapid retreat, (iii) glaciers that underwent cycles of advance and retreat. Furthermore, these categories appear to be linked to the terminus type, with those in category (i) having grounded termini and those in category (ii) characterised by floating ice tongues. We interpret glaciers in category (iii) as surge-type. Glacier geometry (e.g. fjord width and basal topography) is also an important influence on the dynamic re-adjustment of glaciers to changes at their termini. Taken together, the loss of several ice tongues and the recent acceleration in the retreat of numerous marine-terminating glaciers suggests northern Greenland is undergoing rapid change and could soon impact on some large catchments that have capacity to contribute an important component to sea level rise.

Citation: Hill, E. A., Carr, J. R., Stokes, C. R., and Gudmundsson, G. H.: Dynamic changes in outlet glaciers in northern Greenland from 1948 to 2015, The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-17, in review, 2018.
Emily A. Hill et al.
Emily A. Hill et al.
Emily A. Hill et al.

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