Shipping source level estimation for ambient noise forecasting

• Published in: The Journal of the Acoustical Society of America 2012-09, Vol.132 (3_Supplement), p.2057-2057
• Main Authors: Rogers, Jeffrey S., Means, Steven L., Wales, Stephen C.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4755573

The ability to accurately estimate shipping source levels from ambient noise data is an essential step towards creating a forecast model of the ocean soundscape. Source level estimates can be obtained by solving the system of linear equations, governed by the sonar equation, that relate source level to transmission loss (TL) and beamformer response. In this formulation, beamformer response is known and TL can be modeled from ship positions that are determined by a fusion of automatic identification system (AIS) reports and local radar data. Different levels of environmental realism will be taken into account for the TL model by considering two ocean bottom profiles. In particular, a layered sand-limestone bottom and karst sand-limestone bottom will be used in comparison for both 2D and NX2D TL runs. Source levels must be constrained to be positive and are thus solved for with a non-negative least squares (NNLS) algorithm. Estimation of source levels on data collected during the 2007 shallow water array performance (SWAP) experiment will be presented. Simulated ambient noise forecasts for the different sediment profiles will then be compared to real data from the SWAP experiment. [This work was supported by ONR.]