Current and wave measurements using an ADV equipped with automatic velocity range setting

Abstract

Acoustic Doppler Velocimeters (ADV) have been used extensively for wave and current measurements. These pulse-to-pulse coherent systems are most commonly deployed using a pre-set velocity range that determines the maximum measured velocity (dynamic range) and velocity uncertainly (precision). As the velocity field energy can vary significantly (especially during storm events), this limitation requires tradeoffs between the precision and dynamic range of the measurements. We describe the ADV Triton equipped with the auto velocity-range adjustment option that allows the sensor to dynamically select the measurement range based on the environmental state. This ensures that even during the most energetic conditions the velocity measurements are still valid, while still maintaining 1% velocity precision during calm seas. Field tests conducted off of the Scripps Institution of Oceanography Pier demonstrate the Triton's ability to detect the wave-field of up to 0.5 Hz while maintaining 75% or higher coherence between pressure and velocity up to 0.3 Hz. This improved.