CN-121994343-A - Soliton internal wave velocity inversion method based on vector acoustic field energy fluctuation frequency

CN121994343ACN 121994343 ACN121994343 ACN 121994343ACN-121994343-A

Abstract

The invention discloses an island internal wave velocity inversion method based on vector sound field energy fluctuation frequency characteristics, which comprises the steps of arranging a sound source and a vector hydrophone on an expected sound propagation path of island internal waves in a set sea area, transmitting single-frequency sound signals by the sound source, receiving sound pressure and horizontal vibration velocity signals by the vector hydrophone vertical array, calculating sound pressure-horizontal vibration velocity cross-spectrum, obtaining vector sound field fluctuation frequency spectrums of all depths through Fourier transformation, obtaining average energy fluctuation frequency spectrums through average processing, extracting spectral peaks, constructing fluctuation frequencies corresponding to all spectral peaks into actual sound field energy fluctuation frequency vectors, calculating horizontal wave number difference values among different number simple waves of a sound field according to sea environment parameters without island internal waves, combining preset island internal wave velocity ranges, constructing theoretical fluctuation frequency vectors corresponding to each velocity value, calculating similarity of the actual sound field energy fluctuation frequency vectors and the theoretical fluctuation frequency vectors, and taking velocity values corresponding to maximum values, thereby realizing inversion.

Inventors

WU QINGTIAN
JI GUIHUA
WANG GANG
LIANG HENG
ZHANG ZHENZHOU
GAN WEIMING
ZHANG CHUN

Assignees

中国科学院声学研究所南海研究站

Dates

Publication Date: 20260508
Application Date: 20260226

Claims (10)

1. An isolated wavelet velocity inversion method based on vector acoustic field energy fluctuation frequency characteristics comprises the following steps: step S1, arranging a sound source and a vector hydrophone vertical array on an expected sound propagation path of wave in a set sea area soliton, wherein the vector hydrophone vertical array comprises a plurality of array elements; S2, transmitting a single-frequency sound signal by a sound source, and receiving a sound pressure signal and a horizontal vibration speed signal by a vector hydrophone vertical array; S3, calculating sound pressure-horizontal vibration velocity cross spectrum at each array element, and obtaining vector sound field fluctuation spectrum at each depth through Fourier transformation; S4, carrying out average treatment on the vector sound field fluctuation spectrum at each depth to obtain an average energy fluctuation spectrum; S5, extracting spectral peaks in the average energy fluctuation spectrum, and constructing fluctuation frequencies corresponding to the spectral peaks into real-measurement sound field energy fluctuation frequency vectors; Step S6, calculating the horizontal wave number difference value between different numbers of simple waves of the sound field according to marine environment parameters without the soliton internal wave, and constructing a theoretical fluctuation frequency vector corresponding to each preset speed value by combining the preset soliton internal wave speed range; and S7, calculating the similarity between the energy fluctuation frequency vector of the real acoustic field and the theoretical fluctuation frequency vector, taking a preset speed value corresponding to the maximum value of the similarity, and determining the speed value as the speed estimated value of the soliton internal wave in the acoustic propagation path direction, thereby realizing inversion.
2. The method for inverting the velocity of the soliton internal wave based on the energy fluctuation frequency characteristic of the vector acoustic field according to claim 1, wherein the vector hydrophone vertical array in the step S1 is a multichannel receiving array and is used for synchronously acquiring sound pressure signals and horizontal vibration velocity signals at different depths.
3. The method for inversion of soliton internal wave velocity based on vector acoustic field energy fluctuation frequency characteristics according to claim 1, wherein said sound pressure-level vibration velocity cross spectrum of step S3 The method comprises the following steps: Wherein, the For the sound pressure spectrum, The distance, depth and soliton internal wave propagation time respectively, Is the horizontal velocity spectrum, "×" is the conjugate operator.
4. The method for inverting the velocity of soliton internal waves based on the energy fluctuation frequency characteristics of the vector sound field according to claim 1, wherein the abscissa axis unit of the fluctuation spectrum of the vector sound field obtained in the step S3 is a period/hour.
5. The method for inverting the velocity of soliton internal waves based on the energy fluctuation frequency characteristics of the vector sound field according to claim 1, wherein the actual measured sound field energy fluctuation frequency vector constructed in the step S5 is Wherein N is the number of the fluctuation frequency values, The n-th extracted relief frequency value is indicated.
6. The method for inverting the velocity of the soliton internal wave based on the characteristic of the energy fluctuation frequency of the vector acoustic field according to claim 1, wherein the marine environment parameters of the soliton internal wave in the step S6 without the internal wave at least comprise the sea water depth, the sea water sound velocity profile, the sea bottom sound velocity, the density and the absorption coefficient.
7. The method for inverting the velocity of soliton internal waves based on the energy fluctuation frequency characteristics of the vector acoustic field according to claim 5, wherein in the step S6, the method for constructing the theoretical fluctuation frequency vector is as follows: for a certain speed value in a preset soliton internal wave speed range Calculating sound field fluctuation frequency values caused by different number of simple wave coupling according to the following formula : Wherein, the 、 The horizontal wave numbers of the mth and nth simple waves are respectively represented, Representing a real part calculation; Sequencing the fluctuation frequency values caused by different numbers of simple wave coupling from small to large to construct a theoretical fluctuation frequency vector Wherein Q is the number of the fluctuation frequency values, Representing the q-th frequency value after sorting.
8. The method for inverting the velocity of the soliton internal wave based on the characteristic of the energy fluctuation frequency of the vector acoustic field according to claim 7, wherein the method for calculating the similarity in the step S7 is as follows: for real acoustic field energy heave frequency vector Elements of (a) In the theoretical undulating frequency vector Finding the theoretical frequency value with the smallest absolute difference Is marked as Vector of the sum of the values All elements of (3) Corresponding target frequency values Constructing a target frequency vector : Calculating the apparent sound field energy fluctuation frequency vector And a target frequency vector Euclidean distance of overall difference And mapping Euclidean distance of two vectors into normalized similarity : 。
9. The method for velocity inversion of soliton internal waves based on energy fluctuation frequency characteristics of vector acoustic field according to claim 8, wherein in said step S7, velocity estimation values of soliton internal waves in the acoustic propagation path direction are obtained The method comprises the following steps: , wherein, the Respectively representing the minimum value and the maximum value of the preset soliton internal wave velocity range.
10. The method for inverting the velocity of soliton internal waves based on the characteristics of the energy fluctuation frequency of a vector acoustic field according to claim 1, wherein said method is used for suppressing underwater isotropic noise interference.

Description

Soliton internal wave velocity inversion method based on vector acoustic field energy fluctuation frequency Technical Field The invention belongs to the fields of underwater sound engineering, sonar technology, ocean engineering and the like, and relates to an soliton internal wave velocity inversion method based on vector sound field energy fluctuation frequency characteristics. Background Soliton internal waves are a physical sea phenomenon typical of shallow sea continental shelf sea areas. The density-stabilized layered seawater is disturbed by tidal flow and undulating terrain to excite internal tide waves, and the internal tide waves are influenced by strong nonlinear factors in the propagation process and then are changed into large-amplitude soliton internal waves. Soliton internal wave is an important component of a marine power system, and the effects of soliton internal wave on mixing, transportation and energy transmission are key for maintaining marine ecological balance and stable temperature-salt structure. The internal wave of the soliton can induce strong shear flow to threaten the safety of an offshore platform and an underwater vehicle, and the internal wave of the soliton can change the space-time distribution of the sound velocity of the sea water and has influence on marine acoustic applications such as marine acoustic detection, underwater communication and the like. The monitoring method of ocean soliton internal wave is divided into an in-situ actual measurement method, a remote sensing observation method, a numerical simulation method, an acoustic inversion method and the like. In-situ measurement is to arrange observation equipment such as a temperature and salt depth meter, a flow velocity meter and the like in an array at a fixed point, and monitor internal waves by measuring parameters such as temperature, salinity, density, flow velocity and the like of seawater, for example, in a document [1] ("design and application of an internal solitary wave monitoring system based on Tiantong communication", published in the 5 th phase of Tropical ocean theory report "in 2024), and the initial page number is 180). The in-situ measurement method has the advantages of small measurement error and perfect data analysis system, and has the defects of being capable of only monitoring local sea areas and being difficult to capture large-scale spatial distribution and propagation paths of internal waves. The remote sensing observation method mainly utilizes a synthetic aperture radar SAR to capture a modulated signal of an soliton internal wave on sea surface characteristics, identifies the internal wave through a remote sensing image and inverts parameters thereof, such as document [2] ("Nankoni sea bench solitary wave research based on whistle first-order SAR imaging", published in 2 nd phase of China university of ocean, the beginning page number is 10) in 2 months of 2025. The remote sensing observation method has the advantages of realizing large-area observation, capturing the generation source, propagation path and space distribution rule of the internal wave, capturing the sea surface representation of the internal wave, being incapable of reflecting the fine structure of the underwater vertical section and being incapable of communicating with the underwater platform in real time. The numerical simulation method takes field observation data as an initial condition, performs numerical simulation based on an internal wave dynamics model, and realizes predictive monitoring and parameter inversion optimization of internal waves through iterative correction of simulation results and observation data. The numerical simulation method has the advantages of realizing the predictive early warning of internal waves and simulating the whole process of generation, propagation and evolution of the internal waves, and has the defects of high dependence on initial data of field observation, great influence on the accuracy of simulation results by terrain and hydrologic boundary conditions, and being used as a supplementary monitoring method only, for example, document [3] ("study on the space-time characteristics and the generation mechanism of solitary waves in the eastern part of the Hainan island", published in the 5 th stage of ocean mapping in 2025 and 9 months, and the initial page number is 52). The acoustic inversion method is to identify internal waves and invert parameters thereof by utilizing sea water sound velocity profile mutation caused by the internal waves of the solitons and by the propagation characteristic change of the underwater sound signals. The acoustic inversion method has the advantages that the acoustic inversion method can capture the mesoscale propagation characteristics of the internal wave under water, can be communicated with an underwater platform in real time, and can provide solitary internal wave parameter information for the underwater platform in time, such as an