LONG-TERM GOALS

The long-term objective of this work is to develop methods for rapid assessment of seabed variability combined with detailed localized geoacoustic inversions to characterize the bottom for shallow-water environments. Consideration is given to spatial and temporal variability of water column properties common to shallow-water environments and their impact on inversion results. Methods will be developed in recognition of Navy needs for Rapid Environmental Assessment (REA) in littoral regions and corresponding interests in Intelligence, Surveillance, and Reconnaissance (ISR), Anti-Submarine Warfare (ASW), and Mine Warfare (MIW). OBJECTIVES The goals of this project are to develop improved methods for extracting physical seabed parameters in shallow water. Methods will be developed using modal content and dispersion of acoustic fields to determine range dependence in the sediment structure and to construct background models for either linear (perturbative) or non-linear geoacoustic inversion methods such as those based on genetic algorithms (GA) or simulated annealing (SA). APPROACH The approach is based on the analysis of both simulated and measured data representing a variety o