  Several phenomena are known to attenuate waves in the marginal ice zone, such
as wave scattering due to ice floes, viscous dissipation inside the ice and
energy dissipation caused by ice floe interactions. Our aim of this study is to
investigate colliding ice floes and to quantify the Turbulent Kinetic Energy
(TKE) dissipation in the surrounding water through direct observations. The
field work was carried out in Van Mijen Fjord on Svalbard, where an artificial
3x4 m^2 ice floe was sawed out in the 1 m thick ice. Wave motion was simulated
by pulling the ice floe back and forth in an oscillatory manner with two
electrical winches in a 4x6 m^2 pool. Ice floe motion was measured with a range
meter, and the water turbulence was measured with acoustic velocimeters. TKE
frequency spectra were found to contain an inertial subrange where energy was
cascading at a rate proportional to f^(-5/3). From the spectra estimated at
several vertical positions, the TKE dissipation rate was found to decrease
exponentially with depth. The total TKE dissipation rate was estimated by
assuming that turbulence was induced over an area spanning over the ice floe
width and the pool length. The preliminary energy budget suggests that
approximately 60% of the input power from the winches was dissipated in
turbulence, which experimentally confirms that energy dissipation by induced
turbulent water motion is an important mechanism for colliding ice floe fields.
