Broadband acoustic backscattering measurements from the James River

During sampling the a towbody (WASP) and R/V Tidewater were used to measure high-frequency acoustic backscattering throughout the water column in the vicinity of the tidal intrusion front. The echosounders pinged continuously to acquire high-resolution measurements. Transducers (70 kHz to 333 kHz) installed on R/V Tidewater were pole-mounted and downward looking while those installed on the WASP (200 kHz and 333 kHz) were upward looking. The raw data was processed to created calibration echograms containing volume backscattering coefficients [dB re 1/m]. Supporting variables include depth (or range) vectors, distance along the transect, geographic coordinates, and timestamps such that the observations can be aligned with other measurements from the campaign. The instruments were calibrated following standard sphere calibration techniques.