Underwater acoustics: prediction of underwater noise caused by ocean interface processes and anthropogenic activities

Project Leader: Alexander Babanin
Staff: Alexander Babanin
Collaborators: Valeri Lenchine
Sponsors: GHD
Primary Contact: Alexander Babanin (a.babanin@unimelb.edu.au)
Keywords: Oceanography
Disciplines: Infrastructure Engineering
Domains:

Knowledge and understanding of the underwater noise impacts become more important in line with current trends of accelerated development of ports, offshore wind farms and other marine infrastructure. Multiple research works attempt to analyse the underwater background acoustic environment and influences of weather parameters on the background underwater noise levels. Furthermore, impacts from the anthropogenic noise sources may interfere with natural environments and disturb flora and fauna in the affected areas.

Reliable algorithms of background noise prediction can eliminate necessity of underground noise measurements in some cases or reduce requirements to the number of monitoring points and duration of the background monitoring programs. Moreover, accurate predictions of underwater noise propagation will allow us to suggest mitigation measures if necessary.

The proposed research will cover two major themes.

1. Background underwater noise prediction

Scope of this theme should include:

• Literature review of available information on background underwater noise
• Choice of weather parameters that may be better correlated with background noise (ie, wind and waves properties)
• Choice of models to predict underwater background noise based on the environmental factors
• Acquisition of underwater background noise under different environmental conditions
• Background noise data post-processing, analysis of accuracy of predictions made by means of the available models
• Improved, advanced or new models to predict the underwater background noise
• Verification of the improved models versus available or newly obtained data sets
• Recommendations on utilization of the improved model.

2. Verification of underwater noise prediction algorithms

There is a number of standard algorithms and tools that are used for predicting the noise generated by vessels, underwater construction, dredging, offshore wind farms and other human activities. Available software, like dBSea, AcTUP and other tools have been developed in order to predict the underwater noise propagation. Aceppeted guidelines and standards for the prediction of underwater noise, however, are yet to be developed.

Typically, developers of the software do not detail how underwater noise prediction algorithms have been implemented. Besides,, information about accuracy of the underwater noise prediction is sparse and not readily available. This information also may differ, depending on acoustic descriptors used for the underwater modelling tasks.

Scope of this theme should include:

• Initial review of available standards and guidelines for assessment of underwater noise generated by vessels and construction activities
• Review of available underwater noise prediction software
• Design of a case study that involve reference noise sources or construction activities
• Performing underwater measurements for the designed case study
• Comparing the results of measurements with results of modelling obtained from different acoustic algorithms and modelling tools, for a range of acoustic descriptors
• Conclusions and recommendations on the use of different underwater prediction tools and algorithms for construction activities and vessels noise.

Outcomes of this theme are expected to form basis for providing recommendations on prediction of the underwater noise for different noise sources and use of different modelling tools.

Results of the research should allow us prediction of background and anthropogenic underwater noise with reasonable accuracy, and help in identifying zones of high acoustic impact on marine environments, ranging from natural Metocean influences to huma activities.