An Evaluation Of A Bottom-Mounted Doppler Acoustic Profiling Current Meter

Abstract

A bottom-mounted Doppler Acoustic Profiling Current Meter (DAPCM) has been developed and tested in 133 m of water on the northern California continental shelf during the Coastal Ocean Dynamics Experiment (CODE). The prototype DAPCM is a self-contained, battery-powered instrument consisting of an acoustic Doppler profiler and a microprocessor-controlled data logger. The instrument measures vertical profiles of ocean currents with an acoustic range of approximately 150 m and vertical resolution which can be varied from 1 to 32 m. Results of a 90-day comparision between the DAPCM and 8 mechanical current meters (VMCM and VACM) show striking agreement between the two measurement techniques. Mean differences between corresponding acoustic and conventional current measurements were generally less than 0.5 cm/sec and rms differences were approximately 2 cm/sec. Vector correlation coefficients exceeded 0.97 except within 10 m of the sea surface.