Lloyd's mirror effect in fin whale calls and its use to infer the depth of vocalizing animals

Andreia Pereira, Danielle Harris, Peter Tyack, Luis Matias

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

The ocean acoustic Lloyd's Mirror effect (LME) is produced by interference between the direct-path and the sea surface phase-reversed reflection of a sound as observed at a receiver. It results in a frequencydependent interference pattern that can be observed in a spectrogram. Many studies have found variations of spectral characteristics of the 20 Hz 'regular' fin whale call, which seem to reflect geographic differences. However, variability of spectral measurements may occur due to the LME. Using a bout of regular calls with estimated ranges, our study aimed to: 1) show and analyze differences of call features due to the LME; and 2) estimate the depth of the vocalizing whale. The composite spectrogram showed that different spectral characteristics of the calls could be identified within the same bout. We developed transmission loss models considering the LME for a fin whale call generated close to the surface and recorded at the sea bottom by an instrument. Our results suggested that some differences measured in fin whale calls could be related to the LME. Inference of depths of calling whale was not straightforward and needed to be assessed at a finer temporal scale than the full bout of calls.

Original languageEnglish
Title of host publicationProceedings of Meetings on Acoustics
PublisherAcoustical Society of America (ASA)
Chapter070002
Number of pages15
Volume27
DOIs
Publication statusPublished - 2017
Event4th International Conference on the Effects of Noise on Aquatic Life 2016 - Dublin, Ireland
Duration: 10 Jul 201616 Jul 2016
Conference number: 4
http://www.aquaticnoise2016.org/

Publication series

NameProceedings of Meetings on Acoustics
PublisherAcoustical Society of America
ISSN (Print)1939-800X

Conference

Conference4th International Conference on the Effects of Noise on Aquatic Life 2016
Country/TerritoryIreland
CityDublin
Period10/07/1616/07/16
Internet address

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