Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling
According to the Protocol on Environmental Protection to the Antarctic Treaty seismic surveys in the Southern Ocean south of $60\deg$S are exclusively dedicated to academic research. The seismic surveys conducted by the Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany dur...
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ftawi:oai:epic.awi.de:18151 2024-09-15T17:36:48+00:00 Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling Breitzke, Monika 2008 https://epic.awi.de/id/eprint/18151/ https://hdl.handle.net/10013/epic.28688 unknown Breitzke, M. (2008) Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling , 68. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, 3.-6. März, Freiberg. . hdl:10013/epic.28688 EPIC368. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, 3.-6. März, Freiberg. Conference notRev 2008 ftawi 2024-06-24T04:00:13Z According to the Protocol on Environmental Protection to the Antarctic Treaty seismic surveys in the Southern Ocean south of $60\deg$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 and the Amundsen/Bellinghausen Sea. Histograms of the Julian days and water depths covered by these surveys indicate that maximum activities occurred from January to March, and most lines were collected either in shallow waters of 200 to 600 m depth or in deep waters of 3000 to 4000 m depth. To assess the potential risk of future seismic research surveys on marine mammal populations an acoustic wave propagation modeling study is conducted for the Weddell and the Amundsen/Bellinghausen Sea. A viscoelastic 2.5D finite-difference code is used, which allows to simulate the spherical amplitude decay of point sources correctly. A sinusoidal wavelet of 50 Hz dominant frequency serves as source wavelet. Based on CTD measurements, sediment core samplings and sediment echosounder recordings two horizontally-layered, range-independent generic input models are established for the Wedell and the Amundsen/Bellinghausen Sea, one for shallow (400 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 ($\sim$1440 - 1450 m/s), centered in 100 m depth. In the austral summer it is overlain by a warmer, 50 m thick surface layer with slightly higher sound velocities ($\sim$1447 - 1453 m/s). Beneath the low-velocity layer sound velocities increase rapidly to $\sim$1450 - 1460 m/s in 200 m depth, and smoothly to $\sim$1530 m/s in 4700 m depth. The sea floor is mainly covered with soft fine-grained clayey or silty sediments, so that P- and S-wave velocities of 1600 and 200 m/s and a wet bulk density of 1450 kg/m${3}$ are assumed. In a first step the acoustic impact of one ... 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 |
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description |
According to the Protocol on Environmental Protection to the Antarctic Treaty seismic surveys in the Southern Ocean south of $60\deg$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 and the Amundsen/Bellinghausen Sea. Histograms of the Julian days and water depths covered by these surveys indicate that maximum activities occurred from January to March, and most lines were collected either in shallow waters of 200 to 600 m depth or in deep waters of 3000 to 4000 m depth. To assess the potential risk of future seismic research surveys on marine mammal populations an acoustic wave propagation modeling study is conducted for the Weddell and the Amundsen/Bellinghausen Sea. A viscoelastic 2.5D finite-difference code is used, which allows to simulate the spherical amplitude decay of point sources correctly. A sinusoidal wavelet of 50 Hz dominant frequency serves as source wavelet. Based on CTD measurements, sediment core samplings and sediment echosounder recordings two horizontally-layered, range-independent generic input models are established for the Wedell and the Amundsen/Bellinghausen Sea, one for shallow (400 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 ($\sim$1440 - 1450 m/s), centered in 100 m depth. In the austral summer it is overlain by a warmer, 50 m thick surface layer with slightly higher sound velocities ($\sim$1447 - 1453 m/s). Beneath the low-velocity layer sound velocities increase rapidly to $\sim$1450 - 1460 m/s in 200 m depth, and smoothly to $\sim$1530 m/s in 4700 m depth. The sea floor is mainly covered with soft fine-grained clayey or silty sediments, so that P- and S-wave velocities of 1600 and 200 m/s and a wet bulk density of 1450 kg/m${3}$ are assumed. In a first step the acoustic impact of one ... |
format |
Conference Object |
author |
Breitzke, Monika |
spellingShingle |
Breitzke, Monika Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling |
author_facet |
Breitzke, Monika |
author_sort |
Breitzke, Monika |
title |
Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling |
title_short |
Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling |
title_full |
Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling |
title_fullStr |
Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling |
title_full_unstemmed |
Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling |
title_sort |
estimating the acoustic impact of seismic research surveys on marine mammals in the southern ocean using a 2.5d finite-difference code for acoustic wave propagation modeling |
publishDate |
2008 |
url |
https://epic.awi.de/id/eprint/18151/ https://hdl.handle.net/10013/epic.28688 |
genre |
Alfred Wegener Institute Antarc* Antarctic Southern Ocean |
genre_facet |
Alfred Wegener Institute Antarc* Antarctic Southern Ocean |
op_source |
EPIC368. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, 3.-6. März, Freiberg. |
op_relation |
Breitzke, M. (2008) Estimating the acoustic impact of seismic research surveys on marine mammals in the Southern Ocean using a 2.5D finite-difference code for acoustic wave propagation modeling , 68. Jahrestagung der Deutschen Geophysikalischen Gesellschaft, 3.-6. März, Freiberg. . hdl:10013/epic.28688 |
_version_ |
1810492216161861632 |