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. We use the version 3.6 of the global ocean–sea
ice NEMO-LIM model (Nucleus for European Modelling of the Ocean coupled to
the Louvain-la-Neuve sea Ice Model), satellite, buoy and submarine
observations, as well as reanalysis data over the period from 1979 to 2013 to
study these relationships. Overall, the model agrees well with observations
in terms of sea ice extent, concentration and thickness. The seasonal cycle
of sea ice drift speed is reasonably well reproduced by the model.
NEMO-LIM3.6 is able to capture the relationships between the seasonal cycles
of sea ice drift speed, concentration and thickness, with higher drift speed
for both lower concentration and lower thickness, in agreement with
observations. Model experiments are carried out to test the sensitivity of
Arctic sea ice drift speed, thickness and concentration to changes in sea ice
strength parameter P*. These show that higher values of P* generally
lead to lower sea ice deformation and lower sea ice thickness, and that no
single value of P* is the best option for reproducing the observed drift
speed and thickness. The methodology proposed in this analysis provides a
benchmark for a further model intercomparison related to the relationships
between sea ice drift speed and strength, which is especially relevant in the
context of the upcoming Coupled Model Intercomparison Project 6 (CMIP6).
Citation
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230244
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