Sea Ice Velocity Measurements by Upward-Looking Doppler Current Profilers

Abstract

A novel method for measuring sea ice motion using upward-looking Acoustic Doppler Current Profilers is presented. The method overcomes some of the drawbacks inherent in other methods such as lack of temporal resolution or restriction to nearshore areas. Two ADCP's of different sampling configuration were deployed in areas of differing ice climate in the Gulf of St. Lawrence during the winter of 1987/88. Both units proved that they can successfully measure ice velocities while mounted on the ocean bottom. Acoustically measured ice velocities and those measured by radar compare to within 10% in most cases. The variance of the ?error? in the acoustically measured surface vertical velocity increases by almost three orders of magnitude when the surface reflector changes from an ice surface to a wind wave dominated surface. This enables differentiation between ice and open water conditions.