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  • Comparative Studies. Non-European Languages/Literatures  (17)
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  • Comparative Studies. Non-European Languages/Literatures  (17)
RVK
  • 1
    Online Resource
    Online Resource
    Models for acoustic propagation over a seamount of the Louisville Ridge
    Acoustical Society of America (ASA) ; 1981
    In:  The Journal of the Acoustical Society of America Vol. 69, No. S1 ( 1981-05-01), p. S58-S58
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 69, No. S1 ( 1981-05-01), p. S58-S58
    Abstract: Measurements were made of the propagation loss across a seamount of the Louisville Ridge east of New Zealand in 1978. This seamount rises from a depth of some 5000 m to within 490 m of the surface, considerably above the SOFAR axis depth of 1200 m. The measured values of propagation loss recorded by two mid-water receivers for source depths of 244 and 1220 m are compared with the predictions of models of an increasing order of complexity. The simplest model assumes cylindrical spreading plus attenuation up to the seamount, followed by an extra shadowing loss given by SL = 22.2 + 10 log10 (f/230) where the frequency f is in hertz. This model, which is based on the laboratory experiments of Medwin and Spaulding [J. Acoust. Soc. Am. Suppl. 1 66, S76 (1979)], gives a good description for the 1220-m source depth. The data are also compared with the predictions of (i) a modified normal mode model which also incorporates the Medwin-Spaulding shadowing loss beyond the seamount, and (ii) range-dependent computer models.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.386174
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1981
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Project TASMAN TWO—low-frequency sound propagation measurements in the southern ocean
    Acoustical Society of America (ASA) ; 1975
    In:  The Journal of the Acoustical Society of America Vol. 58, No. S1 ( 1975-11-01), p. S85-S85
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 58, No. S1 ( 1975-11-01), p. S85-S85
    Abstract: The seas to the west and south of New Zealand provide unique conditions for the measurement of low-frequency sound propagation. Due to the dominant influence of the antarctic circumpolar current, a series of water masses are stratified between latitude 40 °S and 60 °S. This allowed the design of an experiment to extend a result of Project KIWI ONE—that sound propagation at frequencies below 200 Hz is significantly affected by variations in the sound velocity profile—by relating sound propagation to the oceanographic properties of water masses. From the receiving hydrophones, aircraft flew along five acoustic propagation paths out to a range of 3000 km. These paths were chosen to sample specific water masses and to cross water mass boundaries, which in one case was a large bathymetric feature. Detailed oceanographic data was obtained along the tracks. The results show that below 100 Hz there is an order of magnitude variation in the rate of attenuation from location to location and this may be related to the measured oceanographic properties. [This project was partially funded by ONR Code 486.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2002358
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1975
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  • 3
    Online Resource
    Online Resource
    Vertical directionality of low frequency ambient noise in the South Fiji Basin
    Acoustical Society of America (ASA) ; 1981
    In:  The Journal of the Acoustical Society of America Vol. 70, No. S1 ( 1981-11-01), p. S66-S66
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 70, No. S1 ( 1981-11-01), p. S66-S66
    Abstract: The vertical directionality of ambient noise has been measured at two sites in the South Fiji Basin for the frequency range 10–200 Hz. The results are compared with the depth dependence of omni-directional data taken previously at the same location. [R. W. Bannister, J. Acoust. Soc. Am. Suppl. 1 60, S20 (1976)]. For frequencies above 100 Hz the measured noise is uniformly distributed throughout the water column and is principally due to local wind generated noise. Below 100 Hz there is an additional broad peak in level centered at the deep sound channel axis. This peak is apparently due to long range noise sources received via SOFAR propagation paths. An analysis of the standard deviation could not determine conclusively whether these distant noise sources were storms or ships.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2018980
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1981
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Measurements of low-frequency wind-generated ambient noise in the deep ocean
    Acoustical Society of America (ASA) ; 1981
    In:  The Journal of the Acoustical Society of America Vol. 69, No. S1 ( 1981-05-01), p. S95-S95
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 69, No. S1 ( 1981-05-01), p. S95-S95
    Abstract: Southern Hemisphere oceans provide unique conditions for the measurement of low-frequency wind-generated ambient noise due to their relatively low shipping densities. Results (10–500 Hz) for a single location in the South Fiji Basin [R. W. Bannister, J. Acoust. Soc. Am. 60(S1), S20(A)(1976)] supported the two principal noise generation mechanisms that have been suggested: turbulence, bubbles and spray. For a given local wind speed, higher noise levels were observed than have been reported for the North Atlantic Ocean. This paper is an analysis of wind-generated noise data from additional sites throughout the Tasman Sea—Fiji Basin region. Variation in measured level is compared to wind speed, seastate, and propagation conditions. It appears that local wind-speed is not an absolute indicator of wind generated ambient noise level. [Work supported by NAVSEA.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.385990
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1981
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  • 5
    Online Resource
    Online Resource
    Acoustic propagation characteristics of the South Fiji Basin
    Acoustical Society of America (ASA) ; 1977
    In:  The Journal of the Acoustical Society of America Vol. 61, No. S1 ( 1977-06-01), p. S11-S11
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 61, No. S1 ( 1977-06-01), p. S11-S11
    Abstract: The South Fiji Basin, situated to the north of New Zealand, is a large flat basin with a water depth of 4000 m surrounded almost entirely by ridge systems. A thermal front crosses the northern part of the area. Four propagation loss sections which traversed the basin and margins were made in 1976 using 18-m-depth explosive sources. The data were received on a hydrophone at a depth of 400 m near the center of the basin. Signal enhancement was found near the basin margins, followed by a typically 15 dB signal loss for sources outside the basin. In the vicinity of the thermal front similar signal losses were evident over a range of 50 km. [Work supported by NUSC and DSE.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2015410
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1977
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Resolution of low-frequency attenuation anomalies in the Southern Hemisphere
    Acoustical Society of America (ASA) ; 1987
    In:  The Journal of the Acoustical Society of America Vol. 81, No. S1 ( 1987-05-01), p. S11-S11
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 81, No. S1 ( 1987-05-01), p. S11-S11
    Abstract: During Project KIWI ONE [D. G. Browning et al., Nature 282, 820–822 (1979)] anomalously high values of low-frequency attenuation were observed in the central South Pacific Ocean. Similar results were obtained along a track from New Zealand into the Southern Ocean during Project TASMAN TWO [R. W. Bannister et al., J. Acoust. Soc. Am. 62, 847–859 (1977)] . A recent analysis of oceanographic data by Mellen shows that both regions are included in a relatively high pH contour at the sound channel axis. The corresponding predicted values of attenuation are in reasonable agreement with the measured data.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2024099
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1987
    detail.hit.zdb_id: 1461063-2
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  • 7
    Online Resource
    Online Resource
    Project SPAN 3: Low-frequency ambient sea noise in the South Fiji Basin
    Acoustical Society of America (ASA) ; 1976
    In:  The Journal of the Acoustical Society of America Vol. 60, No. S1 ( 1976-11-01), p. S20-S20
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 60, No. S1 ( 1976-11-01), p. S20-S20
    Abstract: Measurements of low frequency ambient sea noise near the New Zealand coast show relatively low levels due to a generally sparse shipping density in the Southern Hemisphere. [R. W. Bannister et al., J. Acoust. Soc. Am. 55, 418 (1974)] Project SPAN 3 extends these measurements to a deep ocean basin, specifically the South Fiji Basin located to the north of New Zealand. Ambient noise (10–500 Hz) was recorded continuously for one week on five hydrophones which were suspended between 300 and 2300 m depth in 4000 m of water. Supporting propagation loss measurements and ship density surveys were conducted. The results are in agreement with the previously reported data. [Work supported by NUSC and DSE.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2003221
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1976
    detail.hit.zdb_id: 1461063-2
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  • 8
    Online Resource
    Online Resource
    The effect of seamounts on SOFAR propagation: Louisville Ridge II
    Acoustical Society of America (ASA) ; 1980
    In:  The Journal of the Acoustical Society of America Vol. 68, No. S1 ( 1980-11-01), p. S52-S52
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 68, No. S1 ( 1980-11-01), p. S52-S52
    Abstract: A previous paper [R. Bannister et al., J. Acoust. Soc. Am. 55, 417 (A) (1974)] described SOFAR Propagation across a Seamount in the recently discovered Louisville Ridge to the east of New Zealand. This paper reports a more extensive follow-on experiment across two separate peaks in this chain which are located in a water depth of 5000 m. For one Seamount (490 m from the surface) rising considerably above the sound-channel axis (depth 1200 m), SOFAR Propagation from shots at both axis depth and relatively shallow depth (244 m) suffered a 20-dB drop when crossing the peak. This was independent of frequency for 13 octave bands at 63, 125, and 250 Hz. The second Seamount (1100 m from the surface) rose only marginally above the sound-channel axis. SOFAR propagation from axis-depth shots suffered a 10-dB drop independent of frequency when crossing the peak with a rapid recovery to nearly normal propagation conditions during the next 200 knots. Similar behavior was observed for the relatively shallow shots (244 m) except that the initial drop was 20 dB. Comparison is made with results obtained across the South Tasman Rise and another example where surface decoupling effects are also present.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2004783
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1980
    detail.hit.zdb_id: 1461063-2
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  • 9
    Online Resource
    Online Resource
    The effect of the East Australian Current on sound propagation near New Zealand
    Acoustical Society of America (ASA) ; 1979
    In:  The Journal of the Acoustical Society of America Vol. 65, No. S1 ( 1979-06-01), p. S17-S17
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 65, No. S1 ( 1979-06-01), p. S17-S17
    Abstract: It has recently been determined that the East Australian Current swings away from the Australian coast at 32° south latitude flows east across the Tasman Sea past the northern tip of New Zealand. As a result this large current may have a significant effect on sound propagation conditions near the north island of New Zealand. Sound propagation predictions are obtained using a multi profile modelling program. First, comparison is made between sound crossing the current and sound propagation in a normal subtropical water mass. The relative importance of thermal structure, bottom slope and bottom absorption are then determined for current flow near the continental shelf and bathymetric features such as the Lord Howe Rise and Three Kings Islands. Finally, results are compared to data obtained during Project Span Three.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2017139
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1979
    detail.hit.zdb_id: 1461063-2
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  • 10
    Online Resource
    Online Resource
    SOFAR Propagation in the South Pacific Ocean
    Acoustical Society of America (ASA) ; 1974
    In:  The Journal of the Acoustical Society of America Vol. 55, No. 2_Supplement ( 1974-02-01), p. 417-417
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 55, No. 2_Supplement ( 1974-02-01), p. 417-417
    Abstract: Some sound speed profiles responsible for SOFAR propagation in the South Pacific Ocean are significantly different from the type most commonly found in the Northern Hemisphere. Near New Zealand the profile is characterized by a broad region of minimum speed; as a result the arrival structure for signals received at the sound channel axis may be opposite to the classic SOFAR pattern. The largest contribution associated with rays nearest the axis arrives first, followed by a gradual decay of the envelope. Recent oceanographic data obtained by the Scorpio Expedition and the Hakuho Maru and Tui cruises are used to define regions of different sound speed structure for the South Pacific Ocean. Mode theory predictions of the arrival structure for each region are compared with experimental data from Project Kiwi One. The corresponding values of attenuation are determined by both peak and energy methods of analysis.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3437304
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1974
    detail.hit.zdb_id: 1461063-2
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