Ice dynamics in the central Greenland sea

[ 1] Until recently a tongue-shaped sea ice feature formed over the central Greenland Sea each winter. This tongue, known to generations of Norwegian sealers as "Odden,'' sometimes protrudes several hundred kilometres in a northeast direction from the main East Greenland ice edge. Owing to the high wave energy in the Greenland Sea in winter, the formation of sea ice is restricted to locally formed pancake and frazil ice. The Greenland Sea is also a key region for the formation of dense water, and the movement of ice within this tongue will play a crucial role in determining the volume of ice formed over a winter and the subsequent modification to the upper water column through brine drainage. We present results from three drifting "pancake'' buoys released in the Odden in 1997. From the analysis of data from these buoys it was found that the ice predominantly moves in a southwesterly direction, but meanders in any direction are possible, and on timescales above 6 hours the surface wind almost exclusively drives the ice dynamics. Results indicate that pancake ice within the Odden drifts at approximately 4% of the wind speed and at about 40 degrees to the right of the wind.