Observations of the R-reflector and sediment interface reflection at the Shallow Water 06' Central site

Acoustic bottom-interacting measurements from the Shallow Water '06 experiment experiment (frequency range 1-20 kHz) are presented. These are co-located with coring and stratigraphic studies showing a thin (similar to 20 cm) higher sound speed layer overlaying a thicker (similar to 20 m) lower sound speed layer ending at a high-impedance reflector (R reflector). Reflections from the R reflector and analysis of the bottom reflection coefficient magnitude for the upper two sediment layers confirm both these features. Geoacoustic parameters are estimated, dispersion effects addressed, and forward modeling using the parabolic wave equation undertaken. The reflection coefficient measurements suggest a nonlinear attenuation law for the thin layer of sandy sediments. (C) 2008 Acoustical Society of America.This research was supported by the Office of Naval Research. The mooring No. 54 data used for simulation was made available courtesy of the Woods Hole Oceanographic Institution, Ocean Acoustics Laboratory. UTIG contribution 1989