Seasonal variations of sea ice motion in the Canada Basin and their implications

Abstract

Ice velocities and sea level pressure data from Arctic drifting buoys for 1979-85 are used to examine the seasonal variation of sea ice drift in the Canada Basin. A recurring reversal of the mean anticyclonic gyre is demonstrated in late summer, in response to changes in atmospheric forcing. The identification of this reversal of ice motion is significant for numerical modeling of Arctic atmosphere-ocean-ice interactions. Introduction The drift of sea ice in the Arctic Basin has been extensively investigated since Nansen's famous voyage in the "Fram", 1894-96. The main features of the mean pattern of ice circulation [Fel'zenbaum, 1958; Gordienko, 1958] are a large-scale drift away from the Siberian coastline and across the Pole in the Transpolar Drift Stream, with ice exiting the basin through the Fram Strait between Greenland and Svalbard. In the Canada Basin, the motion of the surface waters and ice is characterized by the clockwise Beaufort Gyre that corresponds roughly to the mean surface anticyclone in the atmosphere [Campbell, 1965; Newton, 1973; Carmack, 1986]. Mean velocities of ice drift in the gyre are about 5-6 km d -•. The AIDJEX program in the southern Beaufort Sea investigated ice behavior on a 100 km space scale and one day time scale [Pritchard, 1980]. Subsequently, basin scale data on ice motion have been provided by a network of Arctic drifting buoys [Thorndike and Colony, 1980]. Recent analysis of submarine sonar measurements of ice draft collected by the USS NAUTILUS in August 1958 and the coincident August 1970 transect of the USS QUEENFISH across the Canada Basin along 155 o W indicates that the ice in the central part of the Beaufort Gyre may be thinner and more open than elsewhere [McLaren, 1986] contrary to the earlier interpretation of the NAUTILUS data by Lyon [1961]. McLaren's analysis provided the impetus for a study of ice motion in the Canada Basin. The long-term mean ocean gyre accounts for up to half of the mean ice motion in the Canada Basin, away from coastal areas, but about 70 percent of the variance of the daily ice velocity is contributed by the geostrophic winds [Thorndike and Colony, 1982]. Felzenbaum [1958, cited in Campbell, 1965] notes that surface currents in the Arctic Basin vary little over intervals of Numerical simulation of northern hemisphere sea ice variability, 1951-1980. 90(C3), 4847-4865, 1985.

Changes in Driftwood Delivery to the Canadian Arctic Archipelago: The Hypothesis of Postglacial Oscillations of the Transpolar Drift

“…Yet another mechanism that could affect both the path and turbulence of the TPD is suggested by the seasonal reversals of the Beaufort Gyre (McLaren et al, 1987;Serreze and Barry, 1988). Longer-term changes in the variability of atmospheric and oceanic circulation could result from changes in the strength, persistence, and positions of the Mackenzie and Siberian highs.…”

“…We have no information on how much mixing occurs today or under what conditions it occurs. It seems probable, however, that the recently discovered, brief, annual reversals of the Beaufort Gyre (McLaren et al, 1987) could induce such mixing. These reversals occur in summer when the normal anticyclonic atmospheric circulation over the Canada Basin is replaced by transient cyclones.…”

Regional variations in provenance and abundance of ice-rafted clasts in Arctic Ocean sediments: implications for the configuration of late Quaternary oceanic and atmospheric circulation in the Arctic

“…1). Wind-driven current reversals of up to 30 days duration of the surficial current flow and sea-ice drift are a common feature of both major current systems during late summer months in historic times (McLaren et al, 1987;Serreze et al, 1989a,b;Barry et al, 1993;Proshutinsky and Johnson, 1997). Even with current reversals in the shallow water layer, the underlying water mass moves in a clockwise direction in the Amerasia basin (Serreze et al, 1989b).…”

Remote Sensing of Atmosphere‐cryosphere Interactions in the Polar Basin

“…This feedback is of considerable interest with respect to the recently reported reversal of the normally anticyclonic circulation in the surface ice field in the Beaufort Sea during August (McLaren et al 1987). This annual feature appears to be associated with the replacement of the mean high by a persistent low pressure system in the region.…”