Bottom Backscattering Measured in the Adriatic Sea During the Littoral Warfare Advanced Development 00-3 Experiment

Measurements of ocean bottom backscattering were performed at two shallow water sites (Site 2 and Site F) in the Adriatic Sea as part of the Littoral Warfare Advanced Development 00-3 Experiment. Bottom samples revealed a silty clay bottom at Site 2 and a silty sand bottom at Site F. Scattering strengths were obtained at 0.4 to 5 kHz as a function of mean grazing angle. For all measurements, the grazing angle dependence was fit adequately by assuming a dependence of scattering strength (dB) on the sine of the mean grazing angle: mu + 10 log (sin theta). Bottom scattering strengths were low at the two sites. Scattering strengths at Site 2 were well fit using mu = -40 to -45 dB at low frequencies (400 to 1000 Hz), and mu = -35 to -40 dB at mid frequencies (2.5 to 5 kHz). Although expected to be higher, the LF scattering strengths at Site F fell between mu's of -40 and -5O dB.