Ship-Induced Noise Predictions in the Atlantic and the Pacific: A Comparison of Two Noise Models
Abstract
This report describes differences in the ship-induced, bearing-elevation, noise directionality obtained from different noise models and interprets those differences in terms of the propagation and the environmental components of those models. The two noise models, RANDI and APL, both compute the noise as the incoherent sum of the individual ship contributions; they differ in both their propagation models (ANM and FEPE) and in their environmental models. The directionalities are computed for both the Sargasso Sea and the Gulf of Alaska. The Sargasso Sea results differ significantly with the APL directionality, showing lower levels and a much deeper noise notch. In the Gulf of Alaska, the directionalities are much more similar, with both exhibiting deeper noise notches than in the Sargasso Sea. The disparity in the Sargasso Sea noise notch results primarily because, for the ANM model, the set of modes excited by sources near the continental shelf is disjoint from the modes observed by the array. For the Gulf of Alaska, this "mode-set-disjunction" does not occur, and hence, the ANM more realistically estimates the downslope propagating contributions.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 2006
- Accession Number
- ADA473782
Entities
People
- Iman W. Schurman
- Lisa A. Pflug
- Richard Heitmeyer
- Stephen C. Wales
- Thomas J. Hayward
Organizations
- United States Naval Research Laboratory