Velocity Comparisons from Upward and Downward Acoustic Doppler Current Profilers on the West Florida Shelf

Abstract Current observations are compared from upward- and downward-looking acoustic Doppler current profilers (ADCPs) deployed on the West Florida Shelf (WFS). Despite regional differences, statistical analyses show good agreement between all sets of observations throughout the water column except in the upper few meters where all downward-looking ADCPs exhibit small, but significant, reduction in rms speed values. Evidence suggests that this reduction is mooring related. It is possible that the presence of near-surface bubbles caused by wave activity could bias the near-surface observations. Otherwise, either the upward- or downward-looking mooring systems produce equivalent observations with differences due to spatial variations.