During field operations in the Greenland and Bering Seas in 1978, 1979 and 1983, a number of experiments were carried out in which wave energy was measured along a line of stations running from the open sea deep into an icefield. Wave buoys in the water and accelerometer packages on floes were the instruments employed, with airborne vertical photography to supply information on floe size distribution. It was found that the decay of waves is exponential, with a decay coefficient which generally increases with frequency except for a roll‐over at the highest frequencies. The observations can be fitted reasonably well to a theory of one‐dimensional scattering.

Measurements of surface strain and vertical heave responses to swell were made on a tabular ice island in Kong Oscars Fjord, east Greenland, in September 1978 . At two sites surface strain was measured with a wire strainmeter of 2 m gauge length, and heave was measured with a vertical accelerometer. While the first site was occupied a simultaneous measurement of ambient wave energy was made wit h a wave buoy. The results show that the ice island flexes and heaves in response to the longest component only of the forcing wave field, at periods above 16 s, and wit h a mean strain amplitude of the order of S x 10-7 • The results are compared with theoretical calculations of the response of a thick floating beam. In the light of the theory, t h e flexural behaviour of tabular icebergs and seaice floes is considered and their critical size ranges in relation to sea state are estimated.

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