The long term goals of our research are to: 1. Understand and model the 3-D propagation effects in shallow water and thereby explain some of the variations in acoustic field produced by the presence of shelf-break fronts and internal waves. 2. Apply our long range tomography inversion technique different locations and using different sources and improve the mode arrival estimation to improve it. 3. Explore the possibility of using underwater gliders as acoustic receive platforms and develop

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... essing techniques for data collected using them. 4. Revisit an earlier study to look into sea surface wave effects on modal travel times. OBJECTIVES ♦ Using the data from the J-15 -tow experiment, collected during the SW-06 experiment, we are exploring any evidence of 3-dimentional propagation effects due to frontal/ internal wave reflections. ♦ Using the data from Combustive Sound Sources (CSS) deployed by ARL-Texas we are doing inversions for sediment parameters. ♦ We are exploring the possibility of using gliders as acoustic recording platforms for shallow water applications. The noise characteristics of glider is being evaluated in collaboration with Rutgers University. ♦ The effects of the two tropical storms which passed through the SW-06 experimental area on the acoustic travel times is being investigated. APPROACH The PIs (James Miller and Gopu Potty) took part in the SW-06 on the R/V Knorr and participated in the CSS deployments and conducted a J-15 source tow experiment investigating the 3-D acoustic effects. The CSS data, collected on the WHOI HLA/VLA, will be used to perform inversions for Same as Report (SAR) 18. NUMBER OF PAGES 9 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18