APL-UW Deep Water Propagation 2015-2017: Philippine Sea Data Analysis
University of Washington Applied Physics Laboratory Seattle United States
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This is the final report for Award N00014-15-1-2233. Analysis of low-frequency long-range acoustic signals acquired during the Philippine Sea 2010 experiment Philsea10 was concluded. The pulse spreads for the 200 Hz and 300 Hz signals were found to be negligible.This was supported by time-independent Monte Carlo parabolic equation simulations. The autospectrum of normalized intensity had an excellent match to that of a time-dependent Monte Carlo simulation, but the timescales of fades and glints could not be replicated. The PhilSea10 datasets had considerably more short fades and glints with timescales less than several minutes. The North Pacific ambient noise collection program terminated, and trends for the final seven systems were estimated. Trends for all systems were compared for the 19-year duration of the experiment. Systems in the northeast Pacific demonstrated a decrease in ambient noise systems along the Aleutian chain have either no significant trendor a slight increasing trend systems in the central Pacific Ocean provided contradictory characterizations, having both increasing and decreasing trends. The DOS computer at Kauai died, and was replaced by a Linux system. At the end of the grant, it was determined that the Kauai cable had suffered a break in the shallow near-shore region. Additional contractual authority for some of this research was provided by Award Numbers N00014-14-P-1098 and N00014-17-P-7015.