Quantification of Marine Acoustic Environments

Dylan C. Wilford
Thesis Defense

M.S. in Oceanogaphy

Friday, Jul. 30, 2021, 10:00am

A methodology for the analysis of soundscapes was developed in an attempt to facilitate efficient and accurate soundscape comparisons across time and space. The methodology consists of a collection of traditional soundscape metrics, statistical measures, and acoustic indices that were selected to quantify several salient properties of marine soundscapes: amplitude, impulsiveness, periodicity, and uniformity. The metrics were calculated over approximately 30 hours of semi-continuous passive acoustic data gathered in seven unique acoustic environments. The resultant metric values were compared to a priori descriptions and cross-examined statistically to determine which combination most effectively captured the characteristics of the representative soundscapes. The best measures of amplitude, impulsiveness, periodicity, and uniformity were determined to be SPLrms and SPLpk for amplitude, kurtosis for impulsiveness, an autocorrelation based metric for periodicity, and the Dissimilarity index for uniformity. The metrics were combined to form the proposed “Soundscape Code,” which allows for rapid multidimensional and direct comparisons of salient soundscape properties across time and space. The proposed soundscape code was then applied to a series of soundscapes that were recorded at several deep ocean environments along the US outer continental shelf and the Great Barrier Reef. The comparison and assessment afforded by the soundscape code showed the soundscapes exhibited unique acoustic properties. Multidimensional soundscape code metrics provided a first assessment and helped to establish baseline acoustic properties for the deep ocean OCS sites. This initial characterization will aid in directing further analyses and guiding subsequent assessments to understand soundscape dynamics.


Dylan Wilford graduated with a bachelor’s degree in Facilities Engineering from Massachusetts Maritime Academy in 2014. He worked for several years as a Design Engineer for Siemens Building Technologies where he designed and installed building automation control systems for hospitals and schools.

Currently Dylan is working towards his master’s degree in oceanography with a focus in passive acoustics. Within passive acoustics, Dylan is interested in how passive acoustic data can be used to look at soundscape ecology, how data can be mined for information, and how deployments can be improved.