Pre- and Post-Deployment Recommendations for Single-Point Current Meters and Acoustic Doppler Current Profilers

In this paper, we propose pre-and post-deployment guidelines for both single point current-meters and Acoustic Doppler Current Profilers (ADCPs) to improve awareness of the quality, in terms of accuracy, of the data collected by these instruments among their user community. In the realm of oceanographic instrumentation, single-point current meters and ADCPs are considered to be a well understood and mature technology, however, to ensure that the measurements are not affected by biases due to magnetic anomalies or sensor drifts before and after their deployment, it is necessary to have an understanding of how the velocity vectors are derived from the measurements. Tests performed on three ADCP instruments show that heading errors of up to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10^{\circ}$</tex> can be caused by instruments being deployed in the vicinity of the ADCP. In this paper, we will also investigate the consequences of not compensating for these biases in two oceanographic examples, one of them revealing 16 % horizontal velocity errors in the worst case.