Current meters for measurement of low-speed velocities in ice-covered lakes

Abstract

Two current meters for measurement of low-speed currents in ice-covered lakes, a 'drag-wire' current meter (DWCM) and an acoustic current meter (ACM), are presented. The recording range is 0.1-20 mm s-1 for the DWCM and 0.2-70 mm s-1 for the ACM. The accuracy, obtained from laboratory calibration, is ±30% of the velocity reading and ±10°for direction for the DWCM and ±40% of the velocity reading and ±10°for direction for the ACM. Comparison of the two devices in the field and between simultaneous DWCM recordings and drogue observations, performed in a wind-protected hole in the ice, showed reasonable agreement.