A century of variation in the dependence of Greenland iceberg calving on ice sheet surface mass balance and regional climate change

Bigg, G .R. and Wei, H. L. and Wilton, D. J. and Zhao, Y. and Billings, S. A. and Hanna, Edward and Kadirkamanathan, V. (2014) A century of variation in the dependence of Greenland iceberg calving on ice sheet surface mass balance and regional climate change. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 470 (2166). ISSN 1364-5021

Full content URL: https://doi.org/10.1098/rspa.2013.0662

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Abstract

Iceberg calving is a major component of the total mass balance of the Greenland ice sheet (GrIS). A century-long record of Greenland icebergs comes from the International Ice Patrol's record of icebergs (I48N) passing latitude 48° N, off Newfoundland. I48N exhibits strong interannual variability, with a significant increase in amplitude over recent decades. In this study, we show, through a combination of nonlinear system identification and coupled ocean-iceberg modelling, that I48N's variability is predominantly caused by fluctuation in GrIS calving discharge rather than open ocean iceberg melting. We also demonstrate that the episodic variation in iceberg discharge is strongly linked to a nonlinear combination of recent changes in the surface mass balance (SMB) of the GrIS and regional atmospheric and oceanic climate variability, on the scale of the previous 1-3 years, with the dominant causal mechanism shifting between glaciological (SMB) and climatic (ocean temperature) over time. We suggest that this is a change in whether glacial run-off or under-ice melting is dominant, respectively. We also suggest that GrIS calving discharge is episodic on at least a regional scale and has recently been increasing significantly, largely as a result of west Greenland sources. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Keywords:Climate change, Glacial geology, Oceanography, Climate variation, Greenland, Greenland Ice Sheet, Interannual variability, Non-linear auto-regressive moving averages, Nonlinear combination, Regional climate changes, Surface mass balance, Sea ice, JCOpen
Subjects:F Physical Sciences > F330 Environmental Physics
Divisions:College of Science > School of Geography
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ID Code:25983
Deposited On:10 Feb 2017 10:48

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