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Reducing bias due to noise and attenuation in open-ocean echo integration data

journal contribution
posted on 2023-05-19, 07:58 authored by Ryan, TE, Downie, RA, Kloser, RJ, Keith, G
Measurements of mean volume backscattering strength (Sv, dB re 1 m-1) at ocean-basin scale were made using 38-kHz hull-mounted echosounders on ships of opportunity as part of Australia's Integrated Marine Observing System. The data were collected on vessels of various designs, none of which were purposely built for collecting high-quality acoustic data. A full range of weather extremes affected the quality of the data and could cause large biases in Sv. To remove first order biases and improve processing efficiency, a sequence of new and existing data processing filters were applied in a semi-Automated procedure. These filters were designed to mitigate the effects of three types of noise: impulsive (less than one ping), transient (multiple pings), and background (hours or longer).A filter was also applied to identify signals that were attenuated by air bubbles beneath the transducer. These filters were applied to data from transits across the Southwest Pacific, Indian, and Southern Oceans to produce quality-controlled Sv data sets that are now available from a publicly accessible repository. These filters may be relevant to other open-ocean acoustic observing endeavours, and one or more could be used to mitigate bias in data from a range of acoustic applications.

History

Publication title

ICES Journal of Marine Science

Volume

72

Issue

8

Pagination

2482-2493

ISSN

1054-3139

Department/School

Institute for Marine and Antarctic Studies

Publisher

Academic Press Ltd Elsevier Science Ltd

Place of publication

24-28 Oval Rd, London, England, Nw1 7Dx

Rights statement

Copyright International Council for the Exploration of the Sea 2015.

Repository Status

  • Restricted

Socio-economic Objectives

Oceanic processes (excl. in the Antarctic and Southern Ocean)

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