Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals
According to the Protocol on Environmental Protection to the Antarctic Treaty, adopted 1991, seismic surveys in the Southern Ocean south of 60°S are exclusively dedicated to academic research. The seismic surveys conducted by the Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, G...
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ftawi:oai:epic.awi.de:17308 2024-09-15T17:36:48+00:00 Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals Breitzke, Monika Bohlen, T. 2007 https://epic.awi.de/id/eprint/17308/ https://hdl.handle.net/10013/epic.27640 unknown Breitzke, M. and Bohlen, T. (2007) Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals , AGU Fall Meeting, 10-14 December, San Francisco, CA, USA. . hdl:10013/epic.27640 EPIC3AGU Fall Meeting, 10-14 December, San Francisco, CA, USA. Conference notRev 2007 ftawi 2024-06-24T03:59:51Z According to the Protocol on Environmental Protection to the Antarctic Treaty, adopted 1991, seismic surveys in the Southern Ocean south of 60°S are exclusively dedicated to academic research. The seismic surveys conducted by the Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany during the last 20 years focussed on two areas: The Wedell Sea (60°W - 0°W) and the Amundsen/Bellinghausen Sea (120°W - 60°W). Histograms of the Julian days and water depths covered by these surveys indicate that maximum activities occurred in January and February, and most lines were collected either in shallow waters of 400 - 500 m depth or in deep waters of 2500 - 4500 m depth. To assess the potential risk of future seismic research on marine mammal populations an acoustic wave propagation modeling study is conducted for the Wedell and the Amundsen/Bellinghausen Sea. A 2.5D finite-difference code is used. It allows to simulate the spherical amplitude decay of point sources correctly, considers P- and S-wave velocities at the sea floor and provides snapshots of the wavefield at any spatial and temporal resolution. As source signals notional signatures of GI-, G- and Bolt guns, computed by the NUCLEUS software (PGS) are used. Based on CTD measurements, sediment core samplings and sediment echosounder recordings two horizontally-layered, range-independent generic models are established for the Wedell and the Amundsen/Bellinghausen Sea, one for shallow (500 m) and one for deep water (3000 m). They indicate that the vertical structure of the water masses is characterized by a 100 m thick, cold, low sound velocity layer (~1440 - 1450 m/s), centered in 100 m depth. In the austral summer it is overlain by a warmer, 50 m thick surface layer with slightly higher sound velocities (~1447 - 1453 m/s). Beneath the low-velocity layer sound velocities increase rapidly to ~1450 - 1460 m/s in 200 m depth, and smoothly to ~1530 m/s in 4700 m depth. The sea floor is mainly covered with soft fine-grained clayey or silty ... Conference Object Alfred Wegener Institute Antarc* Antarctic Southern Ocean Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
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description |
According to the Protocol on Environmental Protection to the Antarctic Treaty, adopted 1991, seismic surveys in the Southern Ocean south of 60°S are exclusively dedicated to academic research. The seismic surveys conducted by the Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany during the last 20 years focussed on two areas: The Wedell Sea (60°W - 0°W) and the Amundsen/Bellinghausen Sea (120°W - 60°W). Histograms of the Julian days and water depths covered by these surveys indicate that maximum activities occurred in January and February, and most lines were collected either in shallow waters of 400 - 500 m depth or in deep waters of 2500 - 4500 m depth. To assess the potential risk of future seismic research on marine mammal populations an acoustic wave propagation modeling study is conducted for the Wedell and the Amundsen/Bellinghausen Sea. A 2.5D finite-difference code is used. It allows to simulate the spherical amplitude decay of point sources correctly, considers P- and S-wave velocities at the sea floor and provides snapshots of the wavefield at any spatial and temporal resolution. As source signals notional signatures of GI-, G- and Bolt guns, computed by the NUCLEUS software (PGS) are used. Based on CTD measurements, sediment core samplings and sediment echosounder recordings two horizontally-layered, range-independent generic models are established for the Wedell and the Amundsen/Bellinghausen Sea, one for shallow (500 m) and one for deep water (3000 m). They indicate that the vertical structure of the water masses is characterized by a 100 m thick, cold, low sound velocity layer (~1440 - 1450 m/s), centered in 100 m depth. In the austral summer it is overlain by a warmer, 50 m thick surface layer with slightly higher sound velocities (~1447 - 1453 m/s). Beneath the low-velocity layer sound velocities increase rapidly to ~1450 - 1460 m/s in 200 m depth, and smoothly to ~1530 m/s in 4700 m depth. The sea floor is mainly covered with soft fine-grained clayey or silty ... |
format |
Conference Object |
author |
Breitzke, Monika Bohlen, T. |
spellingShingle |
Breitzke, Monika Bohlen, T. Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals |
author_facet |
Breitzke, Monika Bohlen, T. |
author_sort |
Breitzke, Monika |
title |
Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals |
title_short |
Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals |
title_full |
Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals |
title_fullStr |
Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals |
title_full_unstemmed |
Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals |
title_sort |
modeling acoustic wave propagation in the southern ocean to estimate the acoustic impact of seismic surveys on marine mammals |
publishDate |
2007 |
url |
https://epic.awi.de/id/eprint/17308/ https://hdl.handle.net/10013/epic.27640 |
genre |
Alfred Wegener Institute Antarc* Antarctic Southern Ocean |
genre_facet |
Alfred Wegener Institute Antarc* Antarctic Southern Ocean |
op_source |
EPIC3AGU Fall Meeting, 10-14 December, San Francisco, CA, USA. |
op_relation |
Breitzke, M. and Bohlen, T. (2007) Modeling acoustic wave propagation in the Southern Ocean to estimate the acoustic impact of seismic surveys on marine mammals , AGU Fall Meeting, 10-14 December, San Francisco, CA, USA. . hdl:10013/epic.27640 |
_version_ |
1810492222522523648 |