Combining hydrographic and shipborne ADCP measurements

Observations with a shipborne Acoustic Doppler Current Profiler (ADCP) were made in the Faeroe Bank Channel. When underway in strong winds and rough seas, spurious currents (>50 cm s⁻¹) were observed which vanished when the ship was hove to. On the station strong tidal/inertial currents were detected (ca 20 cm s⁻¹) at two locations, over periods of 12 and 27 h. Transient current estimates were extracted by a least-squares model fit and the residuals filtered by optimum interpolation. The resulting non-divergent currents were combined with geostrophic shear derived from simultaneous CTD and XBT observations. Transport of, and mixing within, the Norwegian Sea overflow confirm previous determinations. The implication of this research for the conduct of WOCE transoceanic sections is described.