Using Dynamic Ocean Circulation Models with Ship-Based and Remote Instrumentation to Improve Echo-Sounding Data Analyses

Modern multibeam echo-sounding sonar systems, coupled with sophisticated optimal estimation algorithms, can provide high-resolution bathymetry and confidence intervals over a region. However, the failure to capture the detailed 4-D sound-speed structurewith discrete measurements of sound-speed profiles (SSP) causes the acoustic propagation models that are an integral part of the bathymetric computation to be in error. Moreover, the time devoted to performing SSP measurements can significantly increasethe total time needed to conduct a bathymetric survey. In this proposal, we outline research intended to determine the feasibility and benefit of including a dynamic ocean circulation model as an integral component of bathymetric surveys and computationprocesses. In Phase I, we'll conduct a numerical study by recreating the 4-D sound-speed structure for the time and region of an archived hydrographic survey. We'll then conduct a cursory analysis of the improvements realized in the bathymetrycomputation in using the ocean model output to compute the effects of variable sound-speed on acoustic propagation. Future phases of the proposed research could leverage the ONR sponsored HFX experiment at the Pacific Missile Range facility in March 2003.If successful, the proposed research could greatly improve the accuracy and cost-effectiveness of bathymetric surveys. These improvements would be largely realized by making better use of remote sensors and decreasing the ship-based SSP measurementfrequency. The ultimate result of the proposed research would be a new bathymetric analysis tool that allows real-time visualization of the ocean model output, automated use of the ocean model to drive the integrated acoustic propagation models andimproved understanding of the overall errors associated with ocean variability.