Seasonal variations in underwater acoustic properties of sea ice, from year-long measurements at Cambridge Bay, Canada

Philippe Blondel; Finn Bichan; Liam Lewry; Hazel Hallett; George McCarthy

Abstract

The Arctic environments are fragile and undergoing rapid changes. Passive Acoustic Monitoring (PAM) measures their acoustic signatures. Autonomous recorders and ocean observatories now provide extremely large time-series, from seconds to years and ultimately decades. Their analyses inform management of the different Arctic regions, working toward compliance with UN Sustainable Development Goal SDG-14. A key component of Arctic environments is sea ice, whose extent decreased by 30%, with predictions of an ice-free Arctic summer within the next decade(s). This study focuses on Cambridge Bay (Canada), and data from the seafloor observatory of Ocean Networks Canada (ONC), consisting in shallow-water ambient sound, ice draft, air temperature and salinity. Ice cover/type are provided by satellite charts from the Government of Canada Ice Archive, using the WMO Egg Code. The period of analysis spans August 2018 to May 2019, including free-water and ice-covered seasons. PAMGuide (Merchant et al., 2015) provided broadband Sound Pressure Levels (SPLs), Third-Octave band Levels (TOLs), Power Spectral Densities (PSDs) and percentile contributions up to 32 kHz. Acoustic events are identified using their broadband SPL relative to the background noise and their respective durations. Frequency analyses show bimodal peaks in the 200 and 800 Hz bands in the winter months, with monthly averaged levels 20 dB above background. Based on comparison with previous studies of ice noise, these are associated with thermal ice cracking. Daily broadband noise increases as temperature increases, confirming quieter periods during ice cover. The number of transient ice events correlates with colder temperatures and increased daily temperature variation. PAM measurements from long-term stations are an essential tool to monitor sea ice evolution with climate change, within the broader context of human impacts and changes in the marine ecosystems.

Original language	English
Pages	viii
Number of pages	1
Publication status	Published - 11 Apr 2022
Event	UK Arctic Science Conference 2022 - Durham University, Durham, UK United Kingdom Duration: 11 Apr 2022 → 13 Apr 2022 https://www.durham.ac.uk/departments/academic/biosciences/research/conferences/

Conference

Conference	UK Arctic Science Conference 2022
Country/Territory	UK United Kingdom
City	Durham
Period	11/04/22 → 13/04/22
Internet address	https://www.durham.ac.uk/departments/academic/biosciences/research/conferences/

Keywords

Underwater Acoustics
ambient sound
polar environments
sea ice

ASJC Scopus subject areas

Acoustics and Ultrasonics

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Cite this

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title = "Seasonal variations in underwater acoustic properties of sea ice, from year-long measurements at Cambridge Bay, Canada",

abstract = "The Arctic environments are fragile and undergoing rapid changes. Passive Acoustic Monitoring (PAM) measures their acoustic signatures. Autonomous recorders and ocean observatories now provide extremely large time-series, from seconds to years and ultimately decades. Their analyses inform management of the different Arctic regions, working toward compliance with UN Sustainable Development Goal SDG-14. A key component of Arctic environments is sea ice, whose extent decreased by 30%, with predictions of an ice-free Arctic summer within the next decade(s). This study focuses on Cambridge Bay (Canada), and data from the seafloor observatory of Ocean Networks Canada (ONC), consisting in shallow-water ambient sound, ice draft, air temperature and salinity. Ice cover/type are provided by satellite charts from the Government of Canada Ice Archive, using the WMO Egg Code. The period of analysis spans August 2018 to May 2019, including free-water and ice-covered seasons. PAMGuide (Merchant et al., 2015) provided broadband Sound Pressure Levels (SPLs), Third-Octave band Levels (TOLs), Power Spectral Densities (PSDs) and percentile contributions up to 32 kHz. Acoustic events are identified using their broadband SPL relative to the background noise and their respective durations. Frequency analyses show bimodal peaks in the 200 and 800 Hz bands in the winter months, with monthly averaged levels 20 dB above background. Based on comparison with previous studies of ice noise, these are associated with thermal ice cracking. Daily broadband noise increases as temperature increases, confirming quieter periods during ice cover. The number of transient ice events correlates with colder temperatures and increased daily temperature variation. PAM measurements from long-term stations are an essential tool to monitor sea ice evolution with climate change, within the broader context of human impacts and changes in the marine ecosystems.",

keywords = "Underwater Acoustics, ambient sound, polar environments, sea ice",

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TY - CONF

T1 - Seasonal variations in underwater acoustic properties of sea ice, from year-long measurements at Cambridge Bay, Canada

AU - Blondel, Philippe

AU - Bichan, Finn

AU - Lewry, Liam

AU - Hallett, Hazel

AU - McCarthy, George

PY - 2022/4/11

Y1 - 2022/4/11

N2 - The Arctic environments are fragile and undergoing rapid changes. Passive Acoustic Monitoring (PAM) measures their acoustic signatures. Autonomous recorders and ocean observatories now provide extremely large time-series, from seconds to years and ultimately decades. Their analyses inform management of the different Arctic regions, working toward compliance with UN Sustainable Development Goal SDG-14. A key component of Arctic environments is sea ice, whose extent decreased by 30%, with predictions of an ice-free Arctic summer within the next decade(s). This study focuses on Cambridge Bay (Canada), and data from the seafloor observatory of Ocean Networks Canada (ONC), consisting in shallow-water ambient sound, ice draft, air temperature and salinity. Ice cover/type are provided by satellite charts from the Government of Canada Ice Archive, using the WMO Egg Code. The period of analysis spans August 2018 to May 2019, including free-water and ice-covered seasons. PAMGuide (Merchant et al., 2015) provided broadband Sound Pressure Levels (SPLs), Third-Octave band Levels (TOLs), Power Spectral Densities (PSDs) and percentile contributions up to 32 kHz. Acoustic events are identified using their broadband SPL relative to the background noise and their respective durations. Frequency analyses show bimodal peaks in the 200 and 800 Hz bands in the winter months, with monthly averaged levels 20 dB above background. Based on comparison with previous studies of ice noise, these are associated with thermal ice cracking. Daily broadband noise increases as temperature increases, confirming quieter periods during ice cover. The number of transient ice events correlates with colder temperatures and increased daily temperature variation. PAM measurements from long-term stations are an essential tool to monitor sea ice evolution with climate change, within the broader context of human impacts and changes in the marine ecosystems.

AB - The Arctic environments are fragile and undergoing rapid changes. Passive Acoustic Monitoring (PAM) measures their acoustic signatures. Autonomous recorders and ocean observatories now provide extremely large time-series, from seconds to years and ultimately decades. Their analyses inform management of the different Arctic regions, working toward compliance with UN Sustainable Development Goal SDG-14. A key component of Arctic environments is sea ice, whose extent decreased by 30%, with predictions of an ice-free Arctic summer within the next decade(s). This study focuses on Cambridge Bay (Canada), and data from the seafloor observatory of Ocean Networks Canada (ONC), consisting in shallow-water ambient sound, ice draft, air temperature and salinity. Ice cover/type are provided by satellite charts from the Government of Canada Ice Archive, using the WMO Egg Code. The period of analysis spans August 2018 to May 2019, including free-water and ice-covered seasons. PAMGuide (Merchant et al., 2015) provided broadband Sound Pressure Levels (SPLs), Third-Octave band Levels (TOLs), Power Spectral Densities (PSDs) and percentile contributions up to 32 kHz. Acoustic events are identified using their broadband SPL relative to the background noise and their respective durations. Frequency analyses show bimodal peaks in the 200 and 800 Hz bands in the winter months, with monthly averaged levels 20 dB above background. Based on comparison with previous studies of ice noise, these are associated with thermal ice cracking. Daily broadband noise increases as temperature increases, confirming quieter periods during ice cover. The number of transient ice events correlates with colder temperatures and increased daily temperature variation. PAM measurements from long-term stations are an essential tool to monitor sea ice evolution with climate change, within the broader context of human impacts and changes in the marine ecosystems.

KW - Underwater Acoustics

KW - ambient sound

KW - polar environments

KW - sea ice

M3 - Abstract

SP - viii

T2 - UK Arctic Science Conference 2022

Y2 - 11 April 2022 through 13 April 2022

ER -