Winter Sea Ice Deformation Measured by Autonomous Buoys During the N-ICE2015 Cruise in the Arctic Ocean North of Svalbard

Abstract:

The motion of the sea ice cover in the Arctic Ocean north of Svalbard is characterized by fast sea ice drift (10 to 70 km/day) during the winter season. The Norwegian Young sea ICE cruise (N-ICE2015) took place in that region from January till June 2015. During this period more than 40 buoys in nested arrays at the distance of 5 to 100 km apart from each other were deployed in 2 deployments (in January/February and in April/May). The buoy types include drifters, snow buoys, ice-mass balance buoys, radiation buoys and wave buoys. The buoys were deployed on the first- and second-year ice that was characteristic for the region. The sea ice dynamics measured by these buoy arrays are explored in relation to the changing atmospheric forcing and internal ice stress during the experiment. The deformation rates obtained from the buoy array are on average higher than measured by buoy experiments in other Arctic regions by earlier experiments. Our preliminary results show a strong connection of the deformation events to the atmospheric forcing. The high sea ice drift speed associated to strong winds is connected to high deformation rates, while the low speeds in the calm periods are connected to the low deformation rates. While it is known that the relationship between the deformation rate and the spatial scale over which it is measured can be represented by a power law (Stern and Lindsay, 2009, JGR), we find that the exponent is not constant over time and space during the experiment. For high ice drift speeds, associated with high wind speeds and a more loose ice cover, the exponent becomes more negative than for lower ice drift speeds and a compressed ice cover.

Figure: Locations of buoy deployments and buoy types for all the buoys deployed during the N-ICE2015 cruise.

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