Determination of compressional wave and shear wave speed profiles in sea ice by crosshole tomography—Theory and experiment

Rajan, Subramaniam D.; Frisk, George V.; Doutt, James A.; Sellers, Cynthia J.

doi:10.1121/1.405436

Cited by 24 publications

(14 citation statements)

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“…McCammon and McDaniel 18 gathered several measurements on attenuation for the purpose of modeling acoustic propagation in sea-ice. They arrived by linear regression at an attenuation of 0.06 dB/m/kHz, which is the same as the lower estimates by Rajan et al 35 and those chosen by Laible and Rajan. 34 In this regression analysis, the values measured by Clee et al 36 became outliers.…”

Section: Elastic Parameters Of Sea-icementioning

confidence: 53%

“…34 In this regression analysis, the values measured by Clee et al 36 became outliers. The values measured by Rajan et al 35 and computed by McCammon and McDaniel 18 are therefore considered to be the best estimate. The relation to shear wave attenuation is given by a s ¼ 6a p .…”

Section: Elastic Parameters Of Sea-icementioning

confidence: 99%

“…The attenuation measured for the compressional wave by Rajan et al 35 varies from 0.06 to 0.282 dB/m/kHz. These estimates were made for a signal at 30 kHz.…”

Section: Elastic Parameters Of Sea-icementioning

confidence: 99%

“…34 Obtaining measurements of the internal elastic parameters of the sea-ice is not trivial. Using cross-hole tomography of an ice-floe Rajan et al 35 were able to produce a detailed image of the internal sound speeds of one ice-floe in the Beaufort sea. Laible and Rajan 34 used these to produce a background model, which agrees well with previous and historical measurements of sound speed in sea-ice.…”

Section: Elastic Parameters Of Sea-icementioning

confidence: 99%

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Measured and modeled acoustic propagation underneath the rough Arctic sea-ice

Hope¹,

Sagen²,

Storheim³

et al. 2017

The Journal of the Acoustical Society of America

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A characteristic surface duct beneath the sea-ice in the Marginal Ice Zone causes acoustic waves to be trapped and continuously interact with the sea-ice. The reflectivity of the sea-ice depends on the thickness, the elastic properties, and its roughness. This work focuses on the influence of sea-ice roughness on long-range acoustic propagation, and on how well the arrival structure can be predicted by the full wave integration model OASES. In 2013, acoustic signals centered at 900 Hz were transmitted every hour for three days between ice-tethered buoys in a drifting network in the Fram Strait. The experiment was set up to study the signal stability in the surface channel below the sea-ice. Oceanographic profiles were collected during the experiment, while a statistical description of the rough sea-ice was established based on historical ice-draft measurements. This environmental description is used as input to the range independent version of OASES. The model simulations correspond fairly well with the observations, despite that a flat bathymetry is used and the sea-ice roughness cannot be fully approximated by the statistical representation used in OASES. Long-range transmissions around 900 Hz are found to be more sensitive to the sea-ice roughness than the elastic parameters.

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Section: Elastic Parameters Of Sea-icementioning

confidence: 53%

Section: Elastic Parameters Of Sea-icementioning

confidence: 99%

“…The attenuation measured for the compressional wave by Rajan et al 35 varies from 0.06 to 0.282 dB/m/kHz. These estimates were made for a signal at 30 kHz.…”

Section: Elastic Parameters Of Sea-icementioning

confidence: 99%

Section: Elastic Parameters Of Sea-icementioning

confidence: 99%

See 2 more Smart Citations

Measured and modeled acoustic propagation underneath the rough Arctic sea-ice

Hope¹,

Sagen²,

Storheim³

et al. 2017

The Journal of the Acoustical Society of America

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“…Rajan et al [25] Rajan et al [25]. It can be seen by comparing the middle and bottom panels of the figure that effective medium theory can predict regions of high and low porosity using wave speed not found in the middle panel.…”

Section: Effective Medium Theory Vs Tomographic Inversionmentioning

confidence: 95%

Wave scattering from cylindrical fluid inclusions in an elastic medium and determination of effective medium properties

Laible¹

1995

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The goal of this thesis is to be able to predict acoustic wave speeds in sea ice with known concentrations of inhomogeneities. To accomplish this, ice is modeled as a solid in which cylindrical fluid brine channels are embedded. The solution is formulated by deriving the scattering from a single cylindrical fluid-filled inclusion in an attenuating elastic medium. The scattering vs. angle results are shown for a laboratory experiment in which a single water-filled cylindrical inclusion is embedded in polypropylene. Four different radius-towavelength ratios of 1.9, 2.4, 8.8 and 11.0 were measured and proved qualitatively consistent with theory. An extension of the single scattering approximation is used to derive effective moduli for multiple fluid-filled cylinders in an elastic medium. The theory assumes the acoustic wavelength in the medium is long compared to the radius of the cylindrical inclusion so that fluctuations in material properties are effectively averaged over. A separate laboratory experiment was conducted using polypropylene to measure compressional wave speeds for different concentrations of inclusions. The experimental results were within 1% of the wave speeds predicted by effective medium theory. The effective compressional wave speeds predicted by this theory were then compared with wave speeds calculated using empirical relations derived from Arctic ice field data. The maximum error between the two is less than 4%. This effective medium theory is extremely useful for acoustic tomography applications and can be expanded to include other inhomogeneity geometries besides cylinders.

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Ambient Noise in the Canadian Arctic

Cook

Barclay

Richards

2020

Springer Polar Sciences

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Numerous studies of ocean ambient noise and under-ice acoustic propagation and reverberation in the Canadian Arctic have been carried out since the 1960s. These studies, largely led by scientists at the Defence Research Establishment Pacific and Defence Research and Development Canada, have been motivated by the need to improve sonar performance prediction in the Arctic over the wide range of seasonal ice, oceanographic, and meteorological conditions at high latitudes. Aside from the valuable insight into the physics of noise generation by sea ice and sound propagation under sea ice, they provide a historical baseline for Arctic ambient noise against which modern measurements can be compared. In 2017, the Department of Fisheries and Oceans added passive acoustic monitoring to their Barrow Strait Real Time Observatory, reporting power spectral density over the acoustic band of 10

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Determination of compressional wave and shear wave speed profiles in sea ice by crosshole tomography—Theory and experiment

Cited by 24 publications

References 0 publications

Measured and modeled acoustic propagation underneath the rough Arctic sea-ice

Measured and modeled acoustic propagation underneath the rough Arctic sea-ice

Wave scattering from cylindrical fluid inclusions in an elastic medium and determination of effective medium properties

Ambient Noise in the Canadian Arctic

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