Influence of the Exchanges between the Atlantic and the Arctic on Sea Ice Volume Variations during the Period 1955–97.

In order to investigate the causes of sea ice volume variations, two simulations have been performed using two different sea ice–ocean models driven by NCEP–NCAR reanalysis data over the period 1955–97. In both models, the largest changes in ice thickness occur in the central Arctic. The anomalous exchanges of sea ice, air, and water between the North Atlantic and the Arctic play a large role in explaining ice volume variations. In particular, the anomaly of oceanic heat transport between Iceland and Norway could alone explain a large part of the simulated ice volume changes. The time evolution of the ice volume appears well correlated with the low-frequency variations of the North Atlantic Oscillation (NAO). Nevertheless, the link between NAO and ice volume changes could operate through different mechanisms between the first and second half of the simulation. The influence of the NAO on the meridional heat transport in the North Atlantic and in the Nordic Seas hold during the whole simulation. Besides, the link between NAO and Fram Strait ice export, which is another important source of ice volume variability, is valid only for the second half of the simulation. [ABSTRACT FROM AUTHOR]