Acoustic tomography for monitoring the Sea of Japan: a pilot experiment

Spindel, Robert C.; Na, Jungyul; Dahl, Peter H.; Oh, Suntaek; Eggen, Christian J.; Kim, Young Gyu; Akulichev, V. A.; Morgunov, Yu. N.

doi:10.1109/joe.2003.811896

Cited by 32 publications

(12 citation statements)

References 2 publications

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“…Our interest to this waveguide is motivated by results of the experiment conducted there in 2006 [27], indicating on high stability of near-axial propagation. Similar behavior was observed in a earlier experiment with a slightly different propagation track [28]. It should be noted that stability of near-axial propagation is atypical for the deep ocean [3,14].…”

Section: Introductionsupporting

confidence: 83%

“…It is recognized that shearless tori can possess extraordinary persistence to chaos [46,[54][55][56][57], therefore, a weakly-divergent beam can survive in the presence of a sound-speed perturbation. Hence, formation of a weaklydivergent beam can be considered as a possible mechanism responsible for unusual stability of near-axial rays, observed in experiments [27,28].…”

Section: Then Introducing New Variablesmentioning

confidence: 99%

“…Weakness of high-number internal-wave modes is a peculiar feature of the Sea of Japan. It is caused by the specific form of the buoyancy frequency profile [28]. In particular, the waveguide for internal waves, determined by the buoyancy frequency profile, is too narrow.…”

Section: Then Introducing New Variablesmentioning

confidence: 99%

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Wave chaos in a randomly inhomogeneous waveguide: Spectral analysis of the finite-range evolution operator

et al. 2013

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The proplem of sound propagation in an oceanic waveguide is considered. Scattering on random inhomogeneity of the waveguide leads to wave chaos. Chaos reveals itself in spectral properties of the finite-range evolution operator (FREO). FREO describes transformation of a wavefield in course of propagation along a finite segment of a waveguide. We study transition to chaos by tracking variations in spectral statistics with increasing length of the segment. Analysis of the FREO is accompanied with ray calculations using the one-step Poincaré map which is the classical counterpart of the FREO. Underwater sound channel in the Sea of Japan is taken for an example. Several methods of spectral analysis are utilized. In particular, we approximate level spacing statistics by means of the Berry-Robnik and Brody distributions, explore the spectrum using the procedure elaborated by A. Relano with coworkers (Relano et al, Phys. Rev. Lett., 2002; Relano, Phys. Rev. Lett., 2008), and analyze modal expansions of the eigenfunctions. We show that the analysis of FREO eigenfunctions is more informative than the analysis of eigenvalue statistics. It is found that near-axial sound propagation in the Sea of Japan preserves stability even over distances of hundreds kilometers. This phenomenon is associated with the presence of a shearless torus in the classical phase space. Increasing of acoustic wavelength degrades scattering, resulting in recovery of localization near periodic orbits of the one-step Poincaré map. Relying upon the formal analogy between wave and quantum chaos, we suggest that the concept of FREO, supported by classical calculations via the one-step Poincaré map, can be efficiently applied for studying chaos-induced decoherence in quantum systems.

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Section: Introductionsupporting

confidence: 83%

Section: Then Introducing New Variablesmentioning

confidence: 99%

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Wave chaos in a randomly inhomogeneous waveguide: Spectral analysis of the finite-range evolution operator

et al. 2013

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“…Распространение звука в мелком море на дальние дистанции (более 100 км) неизбежно сопровождается проявлением многих физических эффектов и процессов [1][2][3][4], которые необходимо учитывать при моделировании акустических полей, оценке их уровней интенсивности и временной структуры сигналов в точках приема. К числу этих эффектов в первую очередь относятся горизонтальная и вертикальная рефракция звуковых волн [5,6], обусловленная влиянием гидрологических условий в районе проведения исследований [7,8], а также рельефом дна на акустической трассе и в ее окрестности [9][10][11].…”

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Результаты Экспериментальных и Теоретических Исследований распространения Импульсных Сигналов в Мелком Море Вдоль Кромки континентального Шельфа

Golov¹,

Morgunov²,

Сорокин³

et al. 2020

Podvodnye Issledovaniia I Robototehnika

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Анализируются результаты натурного эксперимента по распространению импульсных акустических сигналов на шельфе Японского моря в осенне-летний период 2018 года. Цель эксперимента состояла в определении времен прихода и эффективных скоростей распространения сигналов вдоль акустической трассы,ориентированной вдоль кромки шельфа. В ходе теоретического анализа и моделирования распространенияакустических колебаний для условий эксперимента разработана методика прогноза эффективных скоростейраспространения импульсных сигналов на большие расстояния в мелком море. Методика основана на усреднении групповых скоростей первой модальной компоненты сигнала по всей трассе.The purpose of the paper is to present the interpretation of field experiments, dedicated to studying the propagation of impulse acoustic signals on the shelf of the Sea of Japan in the autumn-summer period of 2018. The main goal of the experiments was to determine arrival times and effective sound velocities of the propagation of the pulsed signals in underwater acoustic path trace oriented along the edge of the continental shelf. During theoretical analysis and modeling of sound propagation, the methodology for predicting the effective propagation velocity of pulsed signals over long hauls in the shallow sea was developed. It is based on averaging of the group velocities of the first modal component of the signal over the entire path.

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“…The technical abilities of the receiver provide about a 1 ms resolution for singular pulses. Therefore, with the distance known, we can calculate the velocities of pulse propagation with a high preci sion using acoustic tomography methods and vertical temperature profiles [1,2].…”

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confidence: 99%