Estimation of three-dimensional water column sound speed profiles and sediment compressional wave speed and density profiles using a distributed network of buoys

Broadband data acquired during the Modal Mapping Experiment (MOMAX) V experiment are used to invert simultaneously for the three-dimensional (3D) water column sound speed profiles and the compressional wave speed and density profiles of the seabed in shallow waters off the coast of New Jersey. Linear Frequency Modulation sweep signals in the band 50–300 Hz are transmitted from a nearly stationary source at several discrete positions to a set of freely drifting receivers. Mode travel times are estimated from the signals acquired by the drifting buoys, and these are then used as input data in an inversion algorithm that estimates the acoustic properties of the water column and sediments. The resulting 3D compressional wave speed profiles in the seabed are generally consistent with the one-dimensional profile obtained during the narrowband component of MOMAX V, as well as the results from other experiments in the same area. The validity of the inversion results has also been assessed by the ability of the inverted model to predict the fields measured during the narrowband experiments.