Long-term evaluation of scientific-echosounder performance
Abstract Knudsen, H. P. 2009. Long-term evaluation of scientific-echosounder performance. – ICES Journal of Marine Science, 66: 1335–1340. When scientific acoustic instruments are utilized for quantitative measurements of underwater biological resources, it is extremely important to know their overa...
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsp025 http://academic.oup.com/icesjms/article-pdf/66/6/1335/29134314/fsp025.pdf |
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croxfordunivpr:10.1093/icesjms/fsp025 2024-09-09T19:26:08+00:00 Long-term evaluation of scientific-echosounder performance Knudsen, Hans Petter 2009 http://dx.doi.org/10.1093/icesjms/fsp025 http://academic.oup.com/icesjms/article-pdf/66/6/1335/29134314/fsp025.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 66, issue 6, page 1335-1340 ISSN 1095-9289 1054-3139 journal-article 2009 croxfordunivpr https://doi.org/10.1093/icesjms/fsp025 2024-08-12T04:25:00Z Abstract Knudsen, H. P. 2009. Long-term evaluation of scientific-echosounder performance. – ICES Journal of Marine Science, 66: 1335–1340. When scientific acoustic instruments are utilized for quantitative measurements of underwater biological resources, it is extremely important to know their overall performance, and it is imperative to measure their stability over time. Echosounders mounted on research vessels are therefore routinely calibrated several times annually, often immediately before, during, and after important resource-assessment surveys. In recent years, multifrequency systems for acoustic surveys requiring species identification and categorization based on the frequency response of targets have been introduced, further emphasizing the importance of monitoring instrument performance. In the 1970s, hydrophones and steel spheres were used as alternative references for calibrations. Substantial variations of system performance were observed, however, and gradually it was accepted that the use of hydrophones was inappropriate, because their performance varied more than that of the instruments being calibrated. Not until optimized reference targets were introduced in ca. 1980, was it possible to monitor the stability of acoustic-survey equipment with an acceptable degree of confidence. For the first time, the true, long-term stability of transducers, including ageing effects, could be accurately measured. This paper gives examples of calibration time-series for several Norwegian research vessels operating in various regions from Arctic to tropical waters. Article in Journal/Newspaper Arctic Oxford University Press Arctic Knudsen ENVELOPE(16.057,16.057,67.137,67.137) ICES Journal of Marine Science 66 6 1335 1340 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
description |
Abstract Knudsen, H. P. 2009. Long-term evaluation of scientific-echosounder performance. – ICES Journal of Marine Science, 66: 1335–1340. When scientific acoustic instruments are utilized for quantitative measurements of underwater biological resources, it is extremely important to know their overall performance, and it is imperative to measure their stability over time. Echosounders mounted on research vessels are therefore routinely calibrated several times annually, often immediately before, during, and after important resource-assessment surveys. In recent years, multifrequency systems for acoustic surveys requiring species identification and categorization based on the frequency response of targets have been introduced, further emphasizing the importance of monitoring instrument performance. In the 1970s, hydrophones and steel spheres were used as alternative references for calibrations. Substantial variations of system performance were observed, however, and gradually it was accepted that the use of hydrophones was inappropriate, because their performance varied more than that of the instruments being calibrated. Not until optimized reference targets were introduced in ca. 1980, was it possible to monitor the stability of acoustic-survey equipment with an acceptable degree of confidence. For the first time, the true, long-term stability of transducers, including ageing effects, could be accurately measured. This paper gives examples of calibration time-series for several Norwegian research vessels operating in various regions from Arctic to tropical waters. |
format |
Article in Journal/Newspaper |
author |
Knudsen, Hans Petter |
spellingShingle |
Knudsen, Hans Petter Long-term evaluation of scientific-echosounder performance |
author_facet |
Knudsen, Hans Petter |
author_sort |
Knudsen, Hans Petter |
title |
Long-term evaluation of scientific-echosounder performance |
title_short |
Long-term evaluation of scientific-echosounder performance |
title_full |
Long-term evaluation of scientific-echosounder performance |
title_fullStr |
Long-term evaluation of scientific-echosounder performance |
title_full_unstemmed |
Long-term evaluation of scientific-echosounder performance |
title_sort |
long-term evaluation of scientific-echosounder performance |
publisher |
Oxford University Press (OUP) |
publishDate |
2009 |
url |
http://dx.doi.org/10.1093/icesjms/fsp025 http://academic.oup.com/icesjms/article-pdf/66/6/1335/29134314/fsp025.pdf |
long_lat |
ENVELOPE(16.057,16.057,67.137,67.137) |
geographic |
Arctic Knudsen |
geographic_facet |
Arctic Knudsen |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
ICES Journal of Marine Science volume 66, issue 6, page 1335-1340 ISSN 1095-9289 1054-3139 |
op_doi |
https://doi.org/10.1093/icesjms/fsp025 |
container_title |
ICES Journal of Marine Science |
container_volume |
66 |
container_issue |
6 |
container_start_page |
1335 |
op_container_end_page |
1340 |
_version_ |
1809895807270256640 |