Seasonal variations in sea ice motion and effects on sea ice concentration in the Canada Basin

Authors

  • Mark C. Serreze,

  • Roger G. Barry,

  • Alfred S. McLaren


Abstract

Drifting buoy data, surface pressure, and geostrophic wind analyses from the Arctic Ocean Buoy Program are used to examine seasonal features of the sea ice motion in the Canada Basin for 1979–1985. Although the 7-year annual mean motion in this region is clockwise, the month-to-month motion is highly variable. In late summer to early autumn, the circulation can become net anticlockwise for periods lasting at least 30 days. Results from a linear model demonstrate that these “reversals” of ice motion in the Beaufort Gyre are a wind-driven response to persistent cyclonic activity that contrasts sharply with the predominantly anticyclonic regimes of spring, late autumn, and winter. Model-predicted ice divergences of 0.5% or more per day which can occur during periods of anticlockwise ice motion are in good agreement with values calculated from optimally interpolated velocity gradient fields. Visible band imagery and passive microwave data confirm associated large areal reductions in ice concentration of approximately 20%. Data from under-ice submarine sonar transects and surface pressure records prior to the study period point to frequent recurrences of these late summer to early autumn ice conditions.

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