Evaluating Performance of Acoustic Current Profiler Sensor on Small, Dynamic Surface Buoy

Abstract

A sea surface following buoy equipped with a wave sensor and acoustic Doppler current profiler (ADCP) may be a useful system design option for many different coastal ocean measurement applications. However, previous work has shown that surface buoy-mounted ADCP current profile data can be negatively impacted by buoy motion in dynamic coastal environments. Between 2014 and 2018, a series of three field experiments were conducted at a site in the south Chesapeake Bay to evaluate the performance of acoustic Doppler current profilers installed on small, dynamic surface buoy platforms (< 2 m). The focus of this paper is on results from the third, most recent field experiment conducted during December 2017 – January 2018. This third experiment evaluates potential improvements offered by a new Acoustic Doppler Current Profiler (ADCP) with an integrated Attitude and Heading Reference Sensor (AHRS) and a real-time motion compensation capability. The improved ADCP with ARHS was installed on a small surface buoy in a downward looking configuration. The test buoy system was deployed at the Chesapeake Bay field site alongside a second, nearby ADCP system in a bottom mount serving as a stable reference. Results comparing current profile measurements from buoy and bottom mount sensors indicate significant improvement in the buoy mounted ADCPs performance as compared to the previous two field tests. A summary of the new ADCP instrument employed, measurement methods, field observations, and initial performance evaluation will be presented, along with plans for continuing system development and testing.