Deep water acoustic propagation in the northern Philippine Sea: Comparison of observed ray travel times with a non-acoustic state estimate

Abstract

Six transceivers and one distributed vertical line array (DVLA) receiver were moored in the northern Philippine Sea from April 2010 to May 2011 for low-frequency (325 Hz and below), deep water propagation experiments. The shortest range was about 130 km and the longest about 640 km. A 2009 equipment test yielded travel times between a moored source and a more limited DVLA at about 185 km range along one of the 2010–2011 paths. Experimental goals included understanding the impacts of fronts, eddies, and internal tides on acoustic propagation and determining the utility of acoustic measurements for ocean state estimation. This presentation will report on comparisons between ray travel times computed in a state estimate for the Northern Philippine Sea excluding the ray data, and observations from the 2009 and 2010–2011 experiments. The state estimate uses satellite sea surface height and sea surface temperature observations as well as Argo and XBT profiles. Ray arrival times calculated from the state estimate will be compared to observations as a simple estimate of the novel information present in the data.