Impacts of Ocean Warming on Acoustic Propagation Over Continental Shelf and Slope Regions

Lynch, James F.; Gawarkiewicz, Glen; Lin, Ying‐Tsong; Duda, Timothy F.; Newhall, Arthur E.

doi:10.5670/oceanog.2018.219

Cited by 14 publications

(4 citation statements)

References 26 publications

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“…It has been predicted by acoustic propagation models, e.g., see Fig. 5 from Lynch et al (2018), which shows propagation within the Beaufort Duct at 250 Hz. It has also been numerically and experimentally investigated during the CANAPE experiment.…”

Section: Discussionmentioning

confidence: 72%

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Low-frequency ocean ambient noise on the Chukchi Shelf in the changing Arctic

Bonnel

Kinda

Zitterbart

2021

The Journal of the Acoustical Society of America

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This article presents the study of a passive acoustic dataset recorded on the Chukchi Shelf from October 2016 to July 2017 during the Canada Basin Acoustic Propagation Experiment (CANAPE). The study focuses on the low-frequency (250–350 Hz) ambient noise (after individual transient signals are removed) and its environmental drivers. A specificity of the experimental area is the Beaufort Duct, a persistent warm layer intrusion of variable extent created by climate change, which favors long-range acoustic propagation. The Chukchi Shelf ambient noise shows traditional polar features: it is quieter and wind force influence is reduced when the sea is ice-covered. However, the study reveals two other striking features. First, if the experimental area is covered with ice, the ambient noise drops by up to 10 dB/Hz when the Beaufort Duct disappears. Further, a large part of the noise variability is driven by distant cryogenic events, hundreds of kilometers away from the acoustic receivers. This was quantified using correlations between the CANAPE acoustic data and distant ice-drift magnitude data (National Snow and Ice Data Center).

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Section: Discussionmentioning

confidence: 72%

“…1) and extends at least up to 76 N (Krishfield et al, 2008). Due to the significant impacts of the Beaufort Duct on the acoustic propagation, it has recently received increased attention in the literature Chen et al, 2019;Lynch et al, 2018;Ozanich et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Low-frequency ocean ambient noise on the Chukchi Shelf in the changing Arctic

Bonnel

Kinda

Zitterbart

2021

The Journal of the Acoustical Society of America

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“…At 50 m, a larger intertropical area characterized by increments between 5 and 10 m/s and a visible poleward expansion of the higher values are observed (Arctic Sea, northern Pacific, and the Southern Ocean have differences larger than 10 m/s; Figure S5 in Supporting Information S1). The only area which shows a decrease of the mean annual SS (up to −10 m/s) is the Labrador Sea and the northern Atlantic, which may be related to a shift in the Gulf Stream fronts in this region, potentially changing the sound propagation (Lynch et al., 2018). Major SS variations are found in the northern Pacific Ocean, in the western Arctic (Norwegian and Barents seas), and in the Southern Ocean.…”

Section: Resultsmentioning

confidence: 99%

Ocean Sound Propagation in a Changing Climate: Global Sound Speed Changes and Identification of Acoustic Hotspots

2022

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Climate change is a relevant threat on a global scale, leading to impacts on ecosystems and ocean biodiversity. A considerable fraction of marine life depends on sound. Marine mammals, in particular, exploit sound in all aspects of their life, including feeding and mating. This work explores the impact of climate change in sound propagation by computing the three‐dimensional global field of underwater sound speed. The computation was performed based on present conditions (2006–2016) and a “business‐as‐usual” future climate scenario (Representative Concentration Pathway 8.5), identifying two “acoustic hotspots” where larger sound speed variations are expected. Our results indicate that the identified acoustic hotspots will present substantial climate‐change‐induced sound speed variations toward the end of the century, potentially affecting the vital activities of species in the areas. Evidence is provided of the impact of such variation on underwater sound transmission. As an example of a species impacted by underwater transmission, we considered one marine mammal endangered species, the North Atlantic right whale (Eubalaena glacialis), in the northwestern Atlantic Ocean. To the best of our knowledge, this is the first global‐scale data set of climate‐induced sound speed changes expected under a future scenario. This study provides a starting point for policies oriented research to promote the conservation of marine ecosystems and, in particular, endangered marine mammals.

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“…Sound speed profiles computed from temperature and salinity profiles in the Canada Basin can show a sound speed minimum known as the Beaufort Duct (Duda, 2017) or Beaufort Lens (Lynch et al, 2018), which lies between the PSW and the Atlantic Layer. Sound paths launched horizontally from a source located in this duct are partially shielded from interaction with the ice, experience lower TL, and can be detected at greater distances.…”

Section: B Oceanographic Conditionsmentioning

confidence: 99%

Temporal and spatial dependence of a yearlong record of sound propagation from the Canada Basin to the Chukchi Shelf

Ballard

Sagers

Badiey

et al. 2019

The Journal of the Acoustical Society of America

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During the Canada Basin Acoustic Propagation Experiment (CANAPE), low-frequency signals from five tomographic sources located in the Canada Basin were recorded by an array of hydrophones located on the Chukchi Shelf. The propagation distances ranged from 240 km to 520 km, and the propagation conditions changed from persistently ducted in the basin to seasonally upward refracting on the continental shelf. An analysis of the received level from the tomography sources revealed a spatial dependence in the onset of the seasonal increase in transmission loss, which was correlated with the locations of the sources in the basin. This observation led to the hypothesis that the water advected from Barrow Canyon westward over the continental slope by the Chukchi slope current contributes to the temporal and spatial dependence observed in the acoustic record. The water column properties and ice draft were measured by oceanographic sensors on the basin tomography moorings and by six arrays of oceanographic moorings on the continental shelf to characterize the temporal and spatial variability of the environment. This talk examines the range-dependent measurements and explains the observed variability in the received signals through propagation modeling. [Work sponsored by ONR.]

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Impacts of Ocean Warming on Acoustic Propagation Over Continental Shelf and Slope Regions

Cited by 14 publications

References 26 publications

Low-frequency ocean ambient noise on the Chukchi Shelf in the changing Arctic

Low-frequency ocean ambient noise on the Chukchi Shelf in the changing Arctic

Ocean Sound Propagation in a Changing Climate: Global Sound Speed Changes and Identification of Acoustic Hotspots

Temporal and spatial dependence of a yearlong record of sound propagation from the Canada Basin to the Chukchi Shelf

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