Comparison of acoustic backscatter measurements from a ship-mounted Acoustic Doppler Current Profiler and an EK500 scientific echo-sounder

We compare the calibration of a 150 kHz RD Instruments Acoustic Doppler Current Profiler against the 200 kHz channel of a SIMRAD EK500 scientific echo-sounder. Over a range of mean volume backscattering strength of −88 to −68 dB (relative to a scattering cross-section of 1 m−1), from 10 to 90 m depth, the data from the two instruments were well correlated but with significant slope and offset errors (≈10% and ±3 dB, respectively). After...