Browsing Articles by Author "Korneliussen, Rolf"
Now showing items 1-9 of 9
-
A deep scattering layer under the North Pole pack ice
Snoeijs-Leijonmalm, Pauline; Gjøsæter, Harald; Ingvaldsen, Randi Brunvær; Knutsen, Tor; Korneliussen, Rolf; Ona, Egil; Skjoldal, Hein Rune; Stranne, Christian; Mayer, Larry; Jakobsson, Martin; Gårdfeldt, Katarina (Peer reviewed; Journal article, 2021)The 3.3 million km2 marine ecosystem around the North Pole, defined as the Central Arctic Ocean (CAO), is a blind spot on the map of the world’s fish stocks. The CAO essentially comprises the permanently ice-covered deep ... -
Evaluation of echosounder data preparation strategies for modern machine learning models
Ordonez, Alba; Utseth, Ingrid; Brautaset, Olav; Korneliussen, Rolf; Handegard, Nils Olav (Peer reviewed; Journal article, 2022)Fish stock assessment and management requires accurate estimates of fish abundance, which are typically derived from echosounder observations using acoustic target classification (ATC). Skilled operators are regularly ... -
Finite-amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation
Pedersen, Audun Oppedal; Lunde, Per; Tichy, Frank; Korneliussen, Rolf (Peer reviewed; Journal article, 2022)Abstract – Scientific advice for governmental management of marine resources relies on acoustical observation methods. Quantification and identification of fish and plankton species are often achieved using multi-frequency ... -
Mesopelagic fish gas bladder elongation, as estimated from wideband acoustic backscattering measurements
Khodabandeloo, Babak; Ona, Egil; Pedersen, Geir; Korneliussen, Rolf; Melle, Webjørn Raunsgård; Klevjer, Thor Aleksander (Peer reviewed; Journal article, 2022)Backscattered acoustic energy from a target varies with frequency and carries information about its material properties, size, shape, and orientation. Gas-bearing organisms are strong reflectors of acoustic energy at the ... -
Micronekton biomass distribution, improved estimates across four north Atlantic basins
Klevjer, Thor A.; Melle, Webjørn Raunsgård; Knutsen, Tor; Strand, Espen; Korneliussen, Rolf; Dupont, Nicolas; Salvanes, Anne Gro Vea; Wiebe, Peter H. (Peer reviewed; Journal article, 2019)Distribution of micronekton was investigated during early summer of 2013, using data from a cruise covering the central parts of four north Atlantic basins, the Norwegian Sea (NS), Iceland Sea (ICS), Irminger Sea (IRS), ... -
Nonlinear crosstalk in broadband multi-channel echosounders
Khodabandeloo, Babak; Ona, Egil; Macaulay, Gavin; Korneliussen, Rolf (Peer reviewed; Journal article, 2021)Distortion of acoustic wave caused by nonlinear propagation transfers acoustic energy into higher harmonics of the transmitted signal. When operating several broadband echosounders with non-overlapping frequency bands to ... -
Power budget equations and calibration factors for fish abundance estimation using scientific echo sounders and sonar systems
Lunde, Per; Korneliussen, Rolf (Journal article; Peer reviewed, 2016-07-09)Acoustic methods used in fish abundance estimation constitute a key part of the analytic assessment that makes the basis for abundance estimation of marine resources. The methods rely on power-budget equations and calibrated ... -
Quantitative processing of broadband data as implemented in a scientific split-beam echosounder
Andersen, Lars Nonboe; Chu, Dezhang; Handegard, Nils Olav; Heimvoll, Harald; Korneliussen, Rolf; Macaulay, Gavin; Ona, Egil; Patel, Ruben; Pedersen, Geir (Peer reviewed; Journal article, 2023)The use of quantitative broadband echosounders for biological studies and surveys can offer considerable advantages over narrowband echosounders. These include improved spectral-based target identification and significantly ... -
Structure and functioning of four North Atlantic ecosystems - A comparative study
Melle, Webjørn Raunsgård; Klevjer, Thor A.; Drinkwater, Kenneth F.; Strand, Espen; Naustvoll, Lars Johan; Wiebe, Peter H.; Aksnes, Dag Lorents; Knutsen, Tor; Sundby, Svein; Slotte, Aril; Dupont, Nicolas; Salvanes, Anne Gro Vea; Korneliussen, Rolf; Huse, Geir (Peer reviewed; Journal article, 2020)The epi- and mesopelagic ecosystems of four sub-polar ocean basins, the Labrador, Irminger, Iceland and Norwegian seas, were surveyed during two legs from Bergen, Norway, to Nuuk, Greenland, and back to Bergen. The survey ...