Ice floe collisions and their relation to ice deformation in the Bering Sea during February 1983

During February 1983, we carried out a field study in the Bering Sea on the nature of ice floe collisions and their relation to ice deformation. In the study we deployed on selected ice floes four radar‐tracked buoys, three of which contained triaxial accelerometers. These buoys were initially located in compact ice at a distance of about 100 km from the ice edge, with the separations between pairs of floes ranging from 300 m to 5 km. The buoys then drifted out toward the ice edge at a rate of about 0.5 km h−1, with the acceleration data being telemetered to an adjacent ship. The ice motion divided into two parts: an initial solid body translation with no relative buoy displacement, followed by a rapid transition to a period in which the buoy separations underwent large excursions. Examination of the accelerometer records shows two major collisions which were correlated with the large‐scale ice deformation and hundreds of small collisions which recurred at the ocean swell period. The first major collision occurred at the onset of ice deformation; the second occurred when two floes which had been diverging started to converge. The periodic collisions began following the major collisions; their magnitude depended on the local ice compactness and the size of the ocean swell amplitude.