Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
doi:10.5194/tc-2017-60
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
25 Apr 2017
Review status
This discussion paper is under review for the journal The Cryosphere (TC).
Arctic sea ice drift-strength feedback modelled by NEMO-LIM3.6
David Docquier1, François Massonnet1,2, Neil F. Tandon3, Olivier Lecomte1, and Thierry Fichefet1 1Université catholique de Louvain (UCL), Earth and Life Institute (ELI), Georges Lemaître Centre for Earth and Climate Research (TECLIM), Louvain-la-Neuve, Belgium
2Barcelona Supercomputing Center - Centro Nacional de Supercomputación (BSC-CNS), Earth Sciences Department, Barcelona, Spain
3Environment and Climate Change Canada (ECCC), Climate Research Division, Toronto, Canada
Abstract. Sea ice cover and thickness have substantially decreased in the Arctic Ocean since the beginning of the satellite era. As a result, sea ice strength has been reduced, allowing more deformation and fracturing and leading to increased sea ice drift speed. The resulting increased sea ice export is thought to further lower sea ice concentration and thickness. We use the global ocean-sea ice NEMO-LIM3.6 model (Nucleus for European Modelling of the Ocean coupled to the Louvain-la-Neuve sea Ice Model), satellite and buoy observations, as well as reanalysis data over the period from 1979 to 2013 to study this positive feedback for the first time in such detail. Overall, the model agrees well with observations in terms of sea ice extent, concentration and thickness. Although the seasonal cycle of sea ice drift speed is reasonably well reproduced by the model, the recent positive trend in drift speed is weaker than observations in summer. NEMO-LIM3.6 is able to capture the relationships between sea ice drift speed, concentration and thickness in terms of seasonal cycle, with higher drift speed for both lower concentration and lower thickness, in agreement with observations. Sensitivity experiments are carried out by varying the initial ice strength and show that higher values of ice strength lead to lower sea ice thickness. We demonstrate that higher ice strength results in a more uniform sea ice thickness distribution, leading to lower heat conduction fluxes, which provide lower ice production, and thus lower ice thickness. This shows that the positive feedback between sea ice drift speed and strength is more than just dynamic, more complex than originally thought and that other processes are at play. The methodology proposed in this analysis provides a benchmark for a further model intercomparison related to the interactions between sea ice drift speed and strength.

Citation: Docquier, D., Massonnet, F., Tandon, N. F., Lecomte, O., and Fichefet, T.: Arctic sea ice drift-strength feedback modelled by NEMO-LIM3.6, The Cryosphere Discuss., doi:10.5194/tc-2017-60, in review, 2017.
David Docquier et al.
David Docquier et al.
David Docquier et al.

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