Shallow-Water Transmission

Marsh, H. W.; Schulkin, M.

doi:10.1121/1.1918212

Cited by 57 publications

(28 citation statements)

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“…Using the input parameters representing typical conditions in the shallow water environment (L =50 m, D = 100 m, values of ␣ t and k L as given in Marsh and Schulkin (1962) for sea state 2 and a sandy seabed, and 200 sources), this model demonstrates that the bottom attenuation completely dominates the loss, such that no change in noise level can be observed for all frequencies due to a reduction in pH from 8.1 to 7.4.…”

Section: Shallow Water Environmentmentioning

confidence: 99%

“…The loss mechanisms in the coastal regions of the ocean were parameterized by Marsh and Schulkin (1962) by terms representing cylindrical spreading, absorption, and empirically derived terms which include an effective shallow-water attenuation coefficient and the so-called near-field anomaly. This expression is based on approximately 100 000 measurements in shallow water in a frequency band of 100 Hz to 10 kHz.…”

Section: Shallow Water Environmentmentioning

confidence: 99%

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Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Reeder

Chiu

2010

The Journal of the Acoustical Society of America

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Ocean acidification has been observed since the beginning of the industrial era and is expected to further reduce ocean pH in the future. A significant increase in ocean noise has been suggested based upon the percentage change in acoustic absorption coefficient at low frequencies. Presented here is an analysis using transmission loss models of all relevant loss mechanisms for three environments experiencing a significant near-surface pH reduction of 8.1–7.4. Results show no observable change in the shallow water and surface duct environments, and a statistically insignificant change of less than 0.5 dB for all frequencies in the deep water environment.

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Section: Shallow Water Environmentmentioning

confidence: 99%

Section: Shallow Water Environmentmentioning

confidence: 99%

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Reeder

Chiu

2010

The Journal of the Acoustical Society of America

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“…The first study to investigate the range of Tursiops whistles estimated an active space of up to 25 km in calm weather (sea state 0) in the Moray Firth, Scotland (Janik, 2000). This estimate was based on measurements of whistle source levels combined with assumptions on shallow water sound propagation (Marsh and Schulkin, 1962) and noise level profiles for deep water (Knudsen et al, 1948). In contrast, Quintana-Rizzo and colleagues (2006) reported much smaller estimates of communication ranges on the order of 500 m in a shallow habitat with high noise levels, but with the potential for long-range (>20 km) signal transmission through sound channels (QuintanaRizzo et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Estimated communication range and energetic cost of bottlenose dolphin whistles in a tropical habitat

Jensen¹,

Beedholm²,

Wahlberg³

et al. 2012

The Journal of the Acoustical Society of America

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Bottlenose dolphins (Tursiops sp.) depend on frequency-modulated whistles for many aspects of their social behavior, including group cohesion and recognition of familiar individuals. Vocalization amplitude and frequency influences communication range and may be shaped by many ecological and physiological factors including energetic costs. Here, a calibrated GPS-synchronized hydrophone array was used to record the whistles of bottlenose dolphins in a tropical shallow-water environment with high ambient noise levels. Acoustic localization techniques were used to estimate the source levels and energy content of individual whistles. Bottlenose dolphins produced whistles with mean source levels of 146.766.2 dB re. 1 lPa(RMS). These were lower than source levels estimated for a population inhabiting the quieter Moray Firth, indicating that dolphins do not necessarily compensate for the high noise levels found in noisy tropical habitats by increasing their source level. Combined with measured transmission loss and noise levels, these source levels provided estimated median communication ranges of 750 m and maximum communication ranges up to 5740 m. Whistles contained less than 17 mJ of acoustic energy, showing that the energetic cost of whistling is small compared to the high metabolic rate of these aquatic mammals, and unlikely to limit the vocal activity of toothed whales.

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“…14,15) When the surface was smooth, the correlation value of the surface-reflected pulse was assumed to be high, and the number of data errors increased. Careful setting of PW was effective in reducing the error data, but this effect was insufficient depending on the conditions.…”

Section: Evaluation Of Measurement Errormentioning

confidence: 99%

Evaluation of Reflection Error Using Ultrasonic Telemetry System

Hasegawa

Uchida

Miyamoto

2017

J. Marine Acoust. Soc. Jpn.

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Abstract:Most ultrasonic transmitters (pingers) used for behavioral surveys of aquatic animals send a variety of information by changing the interval of the pulses. The reflection of a pulse generally occurs at the sea surface and/or the bottom. Reflection is a critical problem in considering the measurement error generated by the arrival-time delay of the reflected pulse. We conducted a field experiment to evaluate the effect of reflection, and discussed ways to prevent the effect. In this paper, we used a tracking-type ultrasonic telemetry system. The pinger of the system measures its depth by changing the interval of two pulses. In order to evaluate the paths of the reflected pulses, we measured the difference in arrival time between a direct pulse that propagated the direct path to the hydrophone and reflected pulses. We observed the variation in arrivaltime difference in field experiments. Results showed that reflected surface pulses easily affected the system. Improvements to the ultrasonic telemetry system helped to prevent the effect of reflection, and we demonstrated the effectiveness of the improved system in an additional field experiment. The improved system could measure the depth data without the effects of reflection. We also discuss a more optimal configuration for preventing the measurement error from the additional experimental data.

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Shallow-Water Transmission

Abstract: Expressions and tables are presented for computing the shallow-water transmission loss as a function of bottom type, sea state, frequency. water depth, and range. A table of probable errors is also presented as a function of frequency and range.

Cited by 57 publications

References 0 publications

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Estimated communication range and energetic cost of bottlenose dolphin whistles in a tropical habitat

Evaluation of Reflection Error Using Ultrasonic Telemetry System

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