Model‐data comparisons of deep water ambient noise.

Abstract

During the North Pacific Laboratory (NPAL) Philippine Sea 2009 experiment, a distributed vertical line array (DVLA) was deployed for several weeks in the northern Philippine Sea. The array, described in detail in a previous talk, consisted of two 1000‐m sections, one spanning the sound channel axis and the other covering the deep ocean, extending from above the surface conjugate depth down to within roughly 100 m of the bottom. In this paper, a hybrid propagation model for handling low‐frequency ocean noise will be presented. The model uses analytic solutions (rays) for ranges to 5 km, the parabolic equation for ranges from 5 to 100 km, and normal modes for ranges beyond that. The model predicts ambient noise levels vs depth. The fall off of the ambient noise with depth below the surface conjugate has been reported. The level of the fall off and its frequency dependence are sensitive to the local geo‐acoustics. A geo‐acoustic inversion will be performed using a range‐independent version of the acoustic mo...