Environmental correlates of pack ice noise

Makris, Nicholas C.; Dyer, Ira

doi:10.1121/1.393671

Cited by 50 publications

(29 citation statements)

References 7 publications

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“…The median spectral estimate for May 2013 was compared to historical power spectral estimates, one recorded in a nearby region in April 1982 10 and another from an ice-covered region in the Beaufort Sea in April 1975.…”

Section: Discussionmentioning

confidence: 99%

“…12). 10 The peak at 15 Hz appears less prominent at lower frequencies in 2013 than in 1982. In comparison, a spectral estimate recorded in the Beaufort Sea in April 1975 shows comparable ambient noise levels and structure to 2013 but does not extend to lower fre- 8 (see Table II).…”

Section: B Comparison Of Arctic Ambient Noisementioning

confidence: 94%

“…Email: ecreeves@ucsd.edu environmental variables like wind, air pressure, and temperature. 9,10,11,12 Near the Marginal Ice Zone (MIZ), where the ice is subject to increased wave forcing, noise levels have been shown to be as much as 10 dB higher than those further away from the MIZ.…”

Section: Introductionmentioning

confidence: 99%

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Eastern Arctic ambient noise on a drifting vertical array

Ozanich

Gerstoft

Worcester

et al. 2017

The Journal of the Acoustical Society of America

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Ambient noise in the eastern Arctic was studied from April to September 2013 using a 22 element vertical hydrophone array as it drifted from near the North Pole (89° 23′N, 62° 35′W) to north of Fram Strait (83° 45′N, 4° 28′W). The hydrophones recorded for 108 min/day on six days per week with a sampling rate of 1953.125 Hz. After removal of data corrupted by non-acoustic transients, 19 days throughout the transit period were analyzed. Noise contributors identified include broadband and tonal ice noises, bowhead whale calling, seismic airgun surveys, and earthquake T phases. The bowhead whale or whales detected are believed to belong to the endangered Spitsbergen population, and were recorded when the array was as far north as 86° 24′N. Median power spectral estimates and empirical probability density functions along the array transit show a change in the ambient noise levels corresponding to seismic survey airgun occurrence and received level at low frequencies and transient ice noises at high frequencies. Median power for the same periods across the array shows that this change is consistent in depth. The median ambient noise for May 2013 was among the lowest of the sparse reported observations in the eastern Arctic but comparable to the more numerous observations of western Arctic noise levels.

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Section: Discussionmentioning

confidence: 99%

Section: B Comparison Of Arctic Ambient Noisementioning

confidence: 94%

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Eastern Arctic ambient noise on a drifting vertical array

Ozanich

Gerstoft

Worcester

et al. 2017

The Journal of the Acoustical Society of America

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show abstract

“…Denner (1987, 1988) also report noise levels at 10 Hz detected with drifting buoys as high as 102Pa2/Hz during some intervals in the winter. Makris and Dyer (1986) report a broad peak around 15 Hz reaching 10-3 Pa 2 /Hz associated with ice cracking. Typical levels near 10 Hz during quiet intervals have been reported to be near 10 Pa2/Hz (Kutschale, 1969).…”

Section: Basic Seafloor Pressure Measurementsmentioning

confidence: 97%

Beaufort Ambient Seismo-Acoustics Beneath Ice Cover (BASIC)

Schultz¹,

Lewis²,

Webb³

1993

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“…Makris and Dyer [29] showed that long-term variations of low-frequency ambient noise under pack ice of the central Arctic Ocean correlated highly with composite measures of stress applied to the ice by wind, current, and drift. These compos ites were identified as the horizontal ice stress and the stress moment, and were derived from meteorological and oceanographic data observed simultaneously with the noise.…”

Section: Previous Workmentioning

confidence: 99%

Analysis of seismo-acoustic emission from ice fracturing events during SIMI�94

Dudko¹

1999

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In this thesis the analysis of natural ice events is carried out based on direct measure ments of ice-borne seismo-acoustic waves generated by ice fracturing processes. A major reason for studying this phenomenon is that this acoustic emission is a signifi cant contributor to Arctic ocean ambient noise. Also the Arctic contains rich mineral and oil resources and in order to design mining facilities able to withstand the harsh environmental conditions, we need to have a better understanding of the processes of sea ice mechanics. The data analyzed in this thesis were collected during the Sea Ice Mechanics Initiative SIMI'94 experiment which was carried out in the spring of 1994 in the Central Arctic.One of the contributions of this thesis was the determination of the polarization characteristics of elastic waves using multicomponent geophone data. Polarization methods are well known in seismology, but they have never been used for ice event data processing. In this work one of the polarization methods so called Motion Prod uct Detector method has been successfully applied for localization of ice events and determination of polarization characteristics of elastic waves generated by fractur ing events. This application demonstrates the feasibility of the polarization method for ice event data processing because it allows one to identify areas of high stress concentration and "hot spots" in ridge building process.The identification of source mechanisms is based on the radiation patterns of the events. This identification was carried out through the analysis of the seismo-acoustic emission of natural ice events in the ice sheet. Previous work on natural ice event identification was done indirectly by analyzing the acoustic energy radiated into the water through coupling from elastic energy in the ice sheet.After identification of the events, the estimation of the parameters of fault pro cesses in Arctic ice is carried out. Stress drop, seismic moment and the type of ice fracture are determined using direct near-field measurements of seismo-acoustic sig nals generated by ice events. Estimated values of fracture parameters were in good agreement with previous work for marginal ice zone.During data processing the new phenomenon was discovered: "edge waves", which are waves propagating back and forth along a newly opened ice lead. These waves exhibit a quasi-periodic behavior suggesting some kind of stick-slip generation mecha nism somewhere along the length of the lead. The propagation characteristics of these waves were determined using seismic wavenumber estimation techniques. In the low frequency limit the dispersion can be modeled approximately by an interaction at the lead edges of the lowest order, antisymmetric modes of the infinite plate. Without them the data set around which this thesis revolves simply would not exist.

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Environmental correlates of pack ice noise

Cited by 50 publications

References 7 publications

Eastern Arctic ambient noise on a drifting vertical array

Eastern Arctic ambient noise on a drifting vertical array

Beaufort Ambient Seismo-Acoustics Beneath Ice Cover (BASIC)

Analysis of seismo-acoustic emission from ice fracturing events during SIMI�94

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