Detection Rate Improvements Through Understanding and Modeling Ocean Variability -- 18-004

The transmission loss (TL) observed by sonar operators can differ significantly from that predicted by Navy models. The long-term objective of the proposed work is to understand why these differences occur and improve the target detection predictive capability of the models. Our approach in Phase I is to analyze bistatic sonar data collected on Navy assets. We will examine both cases with model/data agreement and cases with disagreement. Leveraging previous research, we will evaluate possible physical causes for the disagreement with emphasis on scenarios where a surface duct is present to trap acoustic energy. We will attempt to improve the TL model predictions by incorporating additional information such as that derived from in situ environmental sensors or ocean models. The findings will then form the basis of a recommendation for the development of concrete solutions in Phase II.