4.4.4.2 Changes in Patterns of Sea Ice Motion and Modes of Climate Variability that Affect Sea Ice Motion

Gudkovich (1961) hypothesised the existence of two regimes of arctic ice motion driven by large-scale variations in atmospheric circulation. Using a coupled atmosphere-ocean-ice model, Proshutinsky and Johnson (1997) showed that the regimes proposed by Gudkovich (1961) alternated on five- to seven-year intervals. Similarly, Rigor et al. (2002) showed that the changes in the patterns of sea ice motion from the 1980s to the 1990s are related to the Northern Annular Mode (NAM). There is, however, no indication of a long-term trend in ice motion.

In the Antarctic, ice motion undergoes an annual cycle caused by stronger winds in winter. Interannual oscillations are found in all regions, most regularly in the Ross, Amundsen and Bellingshausen Seas with periods of about three to six years (Venegas et al., 2001). These wind-driven ice drift oscillations account for the ice extent oscillations seen in the Antarctic Circumpolar Wave (see Section 3.6.6.2). As for the Arctic, no trend in ice motion is apparent based on the limited data available.