CMICE: A near-surface current meter intercomparison experiment

Abstract

A moored Current Meter Intercomparison Experiment called CMICE was conducted 6 km off the southern coast of Long Island, New York near 40°47′N, 72°30′W during February and March 1976. A total of 20 current meters were deployed on six moorings set in a linear array parallel to the local coastline and topography. The seven instrument types used were the Aanderaa RCM-4, the AMF VACM, the Brookhaven National Laboratory spar buoy system with cylindrical and spherical Marsh-McBirney electromagnetic sensors, the EG&G 850 and CT-3, and the Chesapeake Bay Institute modified ENDECO 105. Current meters were grouped at four depth levels (3.5, 7.4, 15.7, and 25.0 m). Water depth was 27.8 m. Wave data were obtained at the site and 10-m wind data were recorded at the coast 7 km north. Intercomparison of 1 h vector-averaged velocities from instruments of the same type at the same level in the array indicated sufficient horizontal flow homogeneity to allow evaluation of instrument-mooring differences. For properly operating meters the general agreement was typically within ±5 cm s −1 in speed and ±5° in direction for wave heights from 0 to 3.5 m and wave periods from 5 to 9 s. Analysis of instrument and mooring performances shows significant differences in response to surface wave and mooring motion.