Detecting ship wakes for the study of coastal processes

Rätsep, Margus, Parnell, Kevin E., and Soomere, Tarmo (2020) Detecting ship wakes for the study of coastal processes. Journal of Coastal Research, 95 (sp1). pp. 1258-1262.

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View at Publisher Website: https://doi.org/10.2112/SI95-243.1
 
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Abstract

Wakes from contemporary vessels may affect, and in some places dominate, coastal processes in the vicinity of major shipping lanes. The analysis of the properties and impact of wakes has generally been restricted to wakes that can be visually observed in raw data. In this work, spectral analysis of the time series of single-point measurements of water surface elevation from Tallinn Bay is used to highlight the structure of ship wakes using a Short Time Fourier Transform. This method makes it possible to determine the speed and distance of a vessel from the measurement site. Wakes are detected using an algorithm based on Gabor multipliers. The results are compared with vessel passages retrieved from the Automatic Identification System (AIS) data. The algorithm detects the majority of ship wakes that can be visually recognized in spectrograms and misses only those with low signal to noise ratio or those in close proximity to another vessel wake. The calculated speed and distance are consistent with the AIS data except for high-speed vessels sailing at ≥30 knots. The results indicate that by using these techniques the detection of vessel wakes from a single-point wave record is achievable under favorable weather conditions. The methods provide an option for mitigation of the impact of ship wakes in semi-enclosed water bodies.

Item ID: 71505
Item Type: Article (Research - C1)
ISSN: 1551-5036
Keywords: AIS data, Gabor multipliers, windowed Fourier transform
Copyright Information: © Coastal Education and Research Foundation,
Date Deposited: 03 Feb 2022 21:41
FoR Codes: 37 EARTH SCIENCES > 3709 Physical geography and environmental geoscience > 370999 Physical geography and environmental geoscience not elsewhere classified @ 100%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180299 Coastal and estuarine systems and management not elsewhere classified @ 100%
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