CN115422746B - Internal solitary wave parameter extraction algorithm based on underwater glider - Google Patents
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Abstract
An internal solitary wave parameter extraction algorithm based on an underwater glider belongs to the technical field of marine internal solitary wave observation, and adopts a glider matrix to observe, and comprises the following steps: step 1, extracting space-time data observed by an underwater glider, and analyzing the space-time data by adopting a hierarchical clustering analysis method; step 2, carrying out equal-depth interval interpolation on the data in the simultaneous empty data set, calculating Euclidean distance, and judging; step 3, extracting suspicious sequences with equal-close surfaces with maximum depth difference larger than 25m and depth where the maximum depth difference is larger than 20m, and carrying out data and calculation on the machine number, the section number and the average density of the suspicious sequences to obtain ocean layering conditions, floating frequency and internal solitary wave amplitude; and 4, selecting a proper internal solitary wave theory to invert the influence of the internal solitary wave on the equal-density surface according to the optimal application range of the internal solitary wave theory, and outputting a density profile containing the information of the internal solitary wave. The invention can obviously improve the accuracy of the inversion result of the internal solitary wave.
Description
Technical Field
The invention belongs to the technical field of ocean solitary wave observation, and particularly relates to an internal solitary wave parameter extraction algorithm based on an underwater glider.
Background
The traditional method for observing the internal solitary wave mainly comprises the steps of submerged buoy laying, shipborne instrument observation, argo buoy and the like, precious first hand data can be obtained through field observation, sea phenomena can be reflected most truly, and the defects are obvious: such as huge instrument input cost, high labor and time costs for sailing observation, difficulty in realizing large-area observation, and the like. Meanwhile, the method can also be used for observing based on satellite remote sensing, and the method can accurately obtain the information such as the space position, the propagation direction and the like of the internal solitary wave, but cannot obtain the amplitude of the internal solitary wave and the influence of the amplitude of the internal solitary wave on the sea temperature salt and the density jump layer.
As unmanned observation platforms mature gradually, underwater gliders show significant advantages, particularly in: the instrument is simple to collect and release, the data time is continuous, the position area is flexible, and the labor cost is reduced. Meanwhile, the use efficiency of the glider in observing data can be effectively improved by utilizing the research of the underwater glider on the internal wave characteristic parameters and the three-dimensional warm salt. The glider is utilized to carry out ocean observation, the internal wave characteristics are extracted, and the sea area temperature salt fine structure is analyzed and researched, so that the method is beneficial to calculating an underwater sound field, and the implementation of underwater engineering or military operation is ensured.
Since the motion of the underwater glider in the sea is mainly driven by gravity and buoyancy, it is easily affected by the change of the flow field generated by the ocean phenomenon. By utilizing this characteristic of the glider, some students reverse the internal wave characteristic parameters encountered by the glider through the motion condition of the underwater glider. Seven glider observation experiments were performed on the igneous strait by Rudnick et al (2013) from april 2007 to july 2008, and the occurrence of high-frequency internal waves was observed with a period smaller than the acquisition period (3-6 hours) of the glider for the sea water profile information. They estimate the vertical flow rate caused by the internal wave by the pressure measured by the glider and the posture of the glider, and propose an algorithm for calculating the vertical flow rate by the motion equation of the glider and estimating the vertical flow rate by the high-pass filter. During this time, they observed a maximum vertical flow rate exceeding 0.2m/s, and a maximum vertical amplitude of thermocline approaching 200m. Palm et al (2015) have conducted research into marine microstructure in keltersea in 2012 in summer using underwater gliders. They found that the motion inside sea water is mainly dependent on widely distributed ocean internal waves, and that the maximum internal wave amplitude observed exceeds 50m, corresponding to 1/3 of the total water depth. The density jump mixing caused by the internal wave is the main reason for the density reduction of the bottom layer of the seawater, which means that the movement of the density jump is an important mechanism for regulating the seawater exchange in continental shelf areas and deep sea areas. The occurrence of internal solitary waves was observed in south China sea using underwater gliders in August 2017, ma et al (2018). In combination with the mesoscale resolution satellite ocean images, it was demonstrated that the motion of the south sea thermocline is largely dependent on the effects of internal waves. They estimated the period and amplitude of the isolated wave in addition to the inter-range by the vertical velocity and motion characteristics of the glider, 24 minutes and 127 meters respectively.
However, the current research is in the starting stage, the theory and the method in various aspects are still immature, and a great amount of improvement room still exists. In the aspect of observing the internal solitary wave by utilizing the underwater glider, the theoretical basis of the internal solitary wave is lacking, the internal solitary wave parameters are difficult to accurately invert, and the traditional method adopts a single glider to observe, so that the influence of random factors on the motion of the glider is difficult to overcome, thereby affecting the observation precision and being incapable of accurately determining the information such as the amplitude of the internal solitary wave.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention discloses an internal solitary wave parameter extraction algorithm based on an underwater glider, which aims to solve the problems of poor maneuverability, high observation cost and low data precision of the traditional observation means by performing data analysis by combining a space-time analysis method of ocean data, an ocean vertical speed model and an internal solitary wave theoretical model and extracting internal solitary wave characteristic parameters and reversing the influence of the internal solitary wave on ocean temperature and density through the underwater glider matrix observation.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
an internal solitary wave parameter extraction algorithm based on an underwater glider, wherein the extraction algorithm adopts a glider matrix for observation, and the glider matrix refers to: a plurality of underwater gliders are put in at different places in a space matrix form at the same time, and the underwater gliders are used for simultaneous observation, comprising the following steps:
step 1, extracting space-time data observed by an underwater glider, wherein the space-time data comprises a glider machine number, an observation section number, a measuring point longitude and latitude, an observation time, a temperature, a salinity, a density and a water depth, and analyzing the space-time data by adopting a hierarchical clustering analysis method to obtain a simultaneous space-time data set;
and 4, selecting a proper internal solitary wave theory to invert the influence of the internal solitary wave on the isopipe surface according to the ocean layering condition and the internal solitary wave amplitude and the optimal application range of the internal solitary wave theory, combining the internal solitary wave theory with the original profile, and finally outputting a density profile containing the internal solitary wave information.
Preferably, in the step 1, a bottom-up (agglomerate) hierarchical clustering method is adopted, when calculating the distance, firstly, the euclidean distance (Euclidean distance) between samples is calculated, and after the cluster is formed, the distance between the classes is calculated; the class-to-class distance calculation method is a shortest distance method (single link) or a longest distance method (complex link), or a class average distance method (average link) or a center distance method (centroid link).
Preferably, in the step 1, all sections observed by all gliders in the same task are extracted first, and machine numbers n corresponding to each observed section are extracted respectively M Cross section number n P Longitude and latitude lon and lat of water inlet point and average time parameter of profileAnd carrying out dimensionless treatment on the time, as shown in formula (1), so that the time meets the space-time clustering analysis order-of-magnitude requirement:
in the formula (1), the components are as follows,is the average value of single profile observation time, and is expressed in seconds, r t Is the cluster analysis spatial threshold c S With time threshold c T Ratio of (r), i.e. r t =c S /c T ;
Then, a three-dimensional matrix of spatio-temporal data is constructed, having:
suppose that a three-dimensional matrix is divided into m disjoint classes C according to a clustering criterion 1 ,C 2 ,...,C m Two of them are C α And C β The distance of (2) is expressed as:
in the formula (3), delta is a distance operator, delta a,b Representing the Euclidean distance from sample a to sample b;representation class C α Longitude and latitude and average time parameters of the ith sample;
in the calculation, the shortest distance method is expressed as:
the longest distance method is expressed as:
the average distance-like method is expressed as:
the center distance method is expressed as:
in the formula (7), the amino acid sequence of the compound,and->Respectively refer to class C α And C β Center of (C) α And C β Average of samples in (a).
Preferably, in the step 1, the shortest distance method is selected to analyze the time data, and when the shortest distance method is used for analyzing, the original time-space data is divided into M groups of data according to the standard that the longitude and latitude and the average time parameter distance are smaller than respective threshold values, wherein each group contains M profile information; when the same group of spatiotemporal data is the spatiotemporal consistent data, the group of glider-in-flight machine spatiotemporal data has similar observation results; after grouping the data, the group number N of the grouping is output G Machine number N M Cross section number N P : as shown in formula (8), formula (8) is the output data of step one and the input data of step two:
Data 1 =[N G ,N M ,N P ] (8)。
preferably, in the step 2, according to the obtained group number, machine number and profile number, the operation time t, depth dp, temperature tp, salinity st and density ds of all the machine numbers and profile numbers in the same group are extracted for analysis; extracting the maximum submerging depth and the minimum floating depth in different profile observations from the same set of data as interpolation depth intervals of the set of data; the following formula is shown:
in the formula (9):a depth interval representing the interpolation of the set of data; dp (dp) down Represents the submerging depth sequence, dp up Representing a floating depth sequence;
then, carrying out equal-depth interpolation on different section data in the same group of data to obtain interpolation results of temperature, salinity and density of each section in the same depth interval, wherein the interpolation results are shown in the following formula:
and then, the temperature and salt density results of the sections with the same depth and different sections are averaged to obtain an average sequence, wherein the average sequence is shown in the following formula:
in the formula (11), j represents the cross-section number in the same group, and i represents the data number in the same cross-section.
Preferably, in the step 3, the euclidean distance between each profile data and the average data is compared in the same depth interval, and the profile with the largest euclidean distance is selected as the suspicious sequence to perform the next analysis, where the following formula is shown:
in the formula (12): d (D) Eucl (A, B) representing Euclidean distance calculation of the sequences A and B, wherein the specific calculation formula is shown on the right side of the equation;the density sequence of the j-th section is calculated by a Newton interpolation method according to the measured density sequence in the formula (10),representing the average density sequence of the group;
the suspicious section is analyzed to find the maximum value diff of the difference diff between the equal close face and the average equal close face max Its corresponding depth dp md Finally, only extracting the profile data with the equal-density surface difference value larger than 25m and the maximum depth difference value larger than 20m to perform the next analysis, and outputting the machine number N of the suspicious sequence M Cross section number N P Equal-surface-to-average equal-surface maximum difference diff max Maximum difference depth dp md Floating frequency N, average depth intervalEqual depth average Density->Upper and lower layer thickness h 1 、h 2 Density ρ of upper and lower layers 1 、ρ 2 ;
Based on the output data of the suspicious sequence, the suspicious sequence is subjected to the next step of analysis: firstly, local water depth data are found according to the space coordinates of suspicious sections, and then the buoyancy frequency is calculated according to the measured density dataFrequency), as shown in the following equation:
in the formula (13): g represents gravitational acceleration, ρ represents sea water density;
finding the depth with the largest buoyancy frequency as the depth d of the density jump layer pyc The maximum diff of the density difference appears in the previous analysis max Corresponding depth d md Substituting formula (14), and estimating the maximum internal solitary wave amplitude at the density jump layer through linear interpolation or other interpolation modes:
in formula (14): a represents amplitude, diff max Represents the maximum value of the density difference, d md Represents the depth of occurrence of the maximum value of the density difference, d tot Represents the total water depth d pyc Indicating the depth of the dense jump.
Preferably, in the step 4, a suitable internal solitary wave theory is selected to calculate the characteristic parameters of the internal solitary wave according to the thickness of the upper and lower layers and the amplitude of the internal solitary wave (Cui et al, 2021), a suitable internal solitary wave theory is selected to reconstruct the temperature salt profile at the moment of occurrence of the internal solitary wave, wherein the change form of the amplitude along the depth is calculated in a linear fitting mode or in an exponential fitting mode according to the actual situation, so as to form an equal-density change Δp caused by the internal solitary wave, and the equal-density change Δp is compared with the initial density profile P 0 And combining to obtain density profile data which is finally output and contains the influence of the internal solitary wave on the isopipe, wherein the density profile data is shown in the following formula:
P=P 0 +ΔP (15)
in formula (15): p represents the density profile of the output, P 0 Representing the raw density profile, Δp represents the calculated intra-solitary wave-induced isopycnic face change according to the algorithm.
The internal solitary wave parameter extraction algorithm based on the underwater glider has the beneficial effects that:
1. the algorithm for extracting the internal solitary wave characteristic parameters through the glider matrix observation data greatly improves the maneuverability of the internal solitary wave observation, improves the probability of capturing the internal solitary wave data, and simultaneously improves the accuracy of inverting the internal solitary wave characteristic parameters.
2. The invention adopts matrix observation data, can more accurately measure the space-time distribution of local temperature salt, and is more beneficial to the extraction of internal solitary wave characteristic parameters.
3. The invention adopts hierarchical clustering analysis and considers space-time factors, and the data grouping method is closer to the actual situation.
4. The invention adopts the internal solitary wave theory to invert the characteristic parameters, and the inversion result is more accurate.
Drawings
FIG. 1, a flow chart of the present invention;
and 2, an internal solitary wave theory optimal application range diagram.
Detailed Description
The following description is of the preferred embodiments of the invention and is not intended to limit the scope of the invention, but is intended to cover any modifications, equivalents, and improvements within the spirit and principles of the invention.
In an initial embodiment, the invention provides an extraction algorithm of internal solitary wave parameters based on an underwater glider, wherein the extraction algorithm adopts a glider matrix for observation, and the glider matrix refers to: and a plurality of underwater gliders are put in different places in a space matrix form at the same time (namely, the plurality of underwater gliders are arranged in a space matrix form), and the temperature salt space-time variation data of the target sea area can be more accurately captured through the simultaneous observation of the plurality of underwater gliders, so that the characteristic parameters of the internal solitary waves can be more accurately estimated. As shown in fig. 1 and 2, the method comprises the following steps:
step 1, extracting space-time data observed by an underwater glider, wherein the space-time data comprises a glider machine number, an observation section number, a measuring point longitude and latitude, an observation time, a temperature, a salinity, a density and a water depth, and analyzing the space-time data by adopting a hierarchical clustering analysis method to obtain a simultaneous space-time data set;
and 4, selecting a proper internal solitary wave theory to invert the influence of the internal solitary wave on the isopipe surface according to the ocean layering condition and the internal solitary wave amplitude and the optimal application range of the internal solitary wave theory, combining the internal solitary wave theory with the original profile, and finally outputting a density profile containing the internal solitary wave information.
In a further embodiment, as shown in fig. 1 and 2, in the step 1, a bottom-up (agglemerable) hierarchical clustering method is adopted, and the basic principle is that each sample in data is first treated as a class, then the classes are searched for according to the distances, the samples are combined step by step upwards, finally a total class group is formed, when the distances are calculated, firstly, euclidean distances (Euclidean distance) between the samples are calculated, and after the class group is formed, the distances between the classes are calculated; the class-to-class distance calculation method is a shortest distance method (single link) or a longest distance method (complex link), or a class average distance method (average link) or a center distance method (centroid link).
In a further embodiment, as shown in fig. 1 and 2, in the step 1, all sections observed by all gliders in the same task are extracted first, and machine numbers n corresponding to each of the observed sections are extracted respectively M Cross section number n P Longitude and latitude lon and lat of water inlet point and average time parameter of profileAnd carrying out dimensionless treatment on the time, as shown in formula (1), so that the time meets the space-time clustering analysis order-of-magnitude requirement:
in the formula (1), the components are as follows,is the average value of single profile observation time, and is expressed in seconds, r t Is the cluster analysis spatial threshold c S With time threshold c T Ratio of (r), i.e. r t =c S /c T ;
Then, a three-dimensional matrix of spatio-temporal data is constructed, having:
it is assumed that the threshold values of the cluster analysis time and the spatial distance, i.e. c mentioned above, are manually set by the data analyst according to the cluster standard (here the cluster standard refers to the threshold value of the cluster analysis time and the spatial distance S And c T ) The three-dimensional matrix is divided into m disjoint classes C 1 ,C 2 ,...,C m Two of them are C α And C β The distance of (2) is expressed as:
in the formula (3), delta is a distance operator, delta a,b Representing the Euclidean distance from sample a to sample b;representation class C α Longitude and latitude and average time parameters of the ith sample;
in the calculation, the shortest distance method is expressed as:
the longest distance method is expressed as:
the average distance-like method is expressed as:
the center distance method is expressed as:
in the formula (7), the amino acid sequence of the compound,and->Respectively refer to class C α And C β Center of (C) α And C β Average of samples in (a).
In a further embodiment, as shown in fig. 1 and 2, in the step 1, the shortest distance method is selected to analyze the space-time data, and when the shortest distance method is analyzed, the original space-time data is divided into M groups of data according to the criteria that the longitude and latitude and the average time parameter distance are smaller than respective threshold values, wherein each group contains M profile information; when the same group of spatiotemporal data is the spatiotemporal consistent data, the group of glider-in-flight machine spatiotemporal data has similar observation results; after grouping the data, the group number N of the grouping is output G Machine number N M Cross section number N P : as shown in formula (8), formula (8) is the output data of step one and the input data of step two:
Data 1 =[N G ,N M ,N P ] (8)。
in a further embodiment, as shown in fig. 1 and 2, in the step 2, according to the obtained group number, machine number and profile number, the working time t, depth dp, temperature tp, salinity st and density ds of all the machine numbers and profile numbers in the same group are extracted for analysis; extracting the maximum submerging depth and the minimum floating depth in different profile observations from the same set of data as interpolation depth intervals of the set of data; the following formula is shown:
in the formula (9):a depth interval representing the interpolation of the set of data; dp (dp) down Represents the submerging depth sequence, dp up Representing a floating depth sequence;
then, carrying out equal-depth interpolation on different section data in the same group of data to obtain interpolation results of temperature, salinity and density of each section in the same depth interval, wherein the interpolation results are shown in the following formula:
and then, the temperature and salt density results of the sections with the same depth and different sections are averaged to obtain an average sequence, wherein the average sequence is shown in the following formula:
in the formula (11), j represents the cross-section number in the same group, and i represents the data number in the same cross-section.
In a further embodiment, as shown in fig. 1 and 2, in the step 3, euclidean distances between each profile data and the average data are compared in the same depth interval, and a profile with the largest euclidean distance is selected as a suspicious sequence to perform a next analysis, where the following formula is shown:
in the formula (12): d (D) Eucl (A, B) representing Euclidean distance calculations for sequences A and B, the specific calculation formulas being not shown to the right of the equation;the density sequence of the j-th section is calculated by a Newton interpolation method according to the measured density sequence in the formula (10),representing the average density sequence of the group;
the suspicious section is analyzed to find the maximum value diff of the difference diff between the equal close face and the average equal close face max Its corresponding depth dp md Finally, only extracting the profile data with the equal-density surface difference value larger than 25m and the maximum depth difference value larger than 20m to perform the next analysis, and outputting the machine number N of the suspicious sequence M Cross section number N P Equal-surface-to-average equal-surface maximum difference diff max Maximum difference depth dp md Floating frequency N, average depth intervalEqual depth average Density->Upper and lower layer thickness h 1 、h 2 Density ρ of upper and lower layers 1 、ρ 2 ;
Based on the output data of the suspicious sequence, the suspicious sequence is subjected to the next step of analysis: firstly, local water depth data are found according to the space coordinates of suspicious sections, and then the buoyancy frequency is calculated according to the measured density dataFrequency), as shown in the following equation:
in the formula (13): g represents gravitational acceleration, ρ represents sea water density;
finding the depth with the largest buoyancy frequency as the depth d of the density jump layer pyc The maximum diff of the density difference appears in the previous analysis max Corresponding depth d md Substituting formula (14), and estimating the maximum internal solitary wave amplitude at the density jump layer through linear interpolation or other interpolation modes:
in formula (14): a represents amplitude, diff max Represents the maximum value of the density difference, d md Represents the depth of occurrence of the maximum value of the density difference, d tot Represents the total water depth d pyc Indicating the depth of the dense jump.
In a further embodiment, as shown in fig. 1 and 2, in the step 4, a suitable internal solitary wave theory is selected to calculate the characteristic parameters of the internal solitary wave according to the thickness of the upper and lower layers and the amplitude of the internal solitary wave (Cui et al, 2021): the following table shows:
table 1 in solitary wave theory optimum range
Selecting a proper internal solitary wave theory to reconstruct a warm salt profile at the occurrence time of the internal solitary wave, wherein the change form of the amplitude along the depth is calculated in a linear fitting mode or in an exponential fitting mode according to the actual situation, so as to form an equal-density surface change delta P caused by the internal solitary wave, and the equal-density surface change delta P is matched with an initial density profile P 0 And combining to obtain density profile data which is finally output and contains the influence of the internal solitary wave on the isopipe, wherein the density profile data is shown in the following formula:
P=P 0 +ΔP (15)
in formula (15): p represents the density profile of the output, P 0 Representing the raw density profile, Δp represents the calculated intra-solitary wave-induced isopycnic face change according to the algorithm.
Appendix: the expression of the internal solitary wave theory exemplifies:
a) KdV theory its wave front can be expressed as:
b) The internal solitary wave surface under eKdV theory:
c) Wave surface under mKdV theory:
d) The wave surface of the internal solitary wave under the MCC theory:
Claims (7)
1. an internal solitary wave parameter extraction algorithm based on an underwater glider is characterized in that: the extraction algorithm adopts a glider matrix to observe, and the glider matrix refers to: a plurality of underwater gliders are put in at different places in a space matrix form at the same time, and the underwater gliders are used for simultaneous observation, comprising the following steps:
step 1, extracting space-time data observed by an underwater glider, wherein the space-time data comprises a glider machine number, an observation section number, a measuring point longitude and latitude, an observation time, a temperature, a salinity, a density and a water depth, and analyzing the space-time data by adopting a hierarchical clustering analysis method to obtain a simultaneous space-time data set;
step 2, carrying out equal-depth interval interpolation on the data in the simultaneous space data set to obtain equal-depth average data, then comparing the single-section data with the equal-depth average data, calculating Euclidean distance, and judging; the single profile data refers to: when each group of data obtained by hierarchical clustering analysis has a plurality of section data of different gliders at different times, single section information in the same group is single section data;
step 3, extracting suspicious sequences with equal-close surfaces with maximum depth difference larger than 25m and depth where the maximum depth difference is larger than 20m, and carrying out data and calculation on the machine number, the section number and the average density of the suspicious sequences to obtain ocean layering conditions, floating frequency and internal solitary wave amplitude;
and 4, selecting a proper internal solitary wave theory to invert the influence of the internal solitary wave on the isopipe surface according to the ocean layering condition and the internal solitary wave amplitude and the optimal application range of the internal solitary wave theory, combining the internal solitary wave theory with the original profile, and finally outputting a density profile containing the internal solitary wave information.
2. The internal solitary wave parameter extraction algorithm based on an underwater glider as claimed in claim 1, wherein: in the step 1, a bottom-up hierarchical clustering analysis method is adopted, when the distance is calculated, euclidean distance between samples is calculated firstly, and after a class group is formed, the distance between classes is calculated again; the class-to-class distance calculation method is a shortest distance method, a longest distance method, a class average distance method or a center distance method.
3. The internal solitary wave parameter extraction algorithm based on an underwater glider as claimed in claim 2, wherein: in the step 1, all sections observed by all gliders in the same task are extracted first, and the machine number n corresponding to each observed section is extracted respectively M Cross section number n P Longitude and latitude lon and lat of water inlet point and average time parameter of profileAnd carrying out dimensionless treatment on the time, as shown in formula (1), so that the time meets the space-time clustering analysis order-of-magnitude requirement:
in the formula (1), the components are as follows,is the average value of single profile observation time, and is expressed in seconds, r t Is the cluster analysis spatial threshold c s With time threshold c T Ratio of (r), i.e. r t =c s /c T ;
Then, a three-dimensional matrix of spatio-temporal data is constructed, having:
suppose that a three-dimensional matrix is divided into m disjoint classes C according to a clustering criterion 1 ,C 2 ,...,C m Two of them are C α And C β The distance of (2) is expressed as:
in the formula (3), delta is a distance operator, delta a,b Representing the Euclidean distance from sample a to sample b;representation class C α Longitude and latitude and average time parameters of the ith sample;
in the calculation, the shortest distance method is expressed as:
the longest distance method is expressed as:
the average distance-like method is expressed as:
the center distance method is expressed as:
4. An internal solitary wave parameter extraction algorithm based on an underwater glider as claimed in claim 3 wherein: in the step 1, the shortest distance method is selected to analyze the time-space data, and when the shortest distance method is analyzed, the original time-space data is divided into M groups of data according to the standard that the longitude and latitude and the average time parameter distance are smaller than respective threshold values, wherein each group of data comprises M section information; when the same group of spatiotemporal data is the spatiotemporal consistent data, the group of glider-in-flight machine spatiotemporal data has similar observation results; after grouping the data, the group number N of the grouping is output G Machine number N M Cross section number N P : as shown in formula (8):
Data 1 =[N G ,N M ,N P ] (8)。
5. the internal solitary wave parameter extraction algorithm based on an underwater glider as claimed in claim 4, wherein: in the step 2, according to the obtained group number, machine number and section number, extracting the operation time t, depth dp, temperature tp, salinity st and density ds of all the machine numbers and section numbers in the same group for analysis; extracting the maximum submerging depth and the minimum floating depth in different profile observations from the same set of data as interpolation depth intervals of the set of data; the following formula is shown:
in the formula (9):a depth interval representing the interpolation of the set of data; dp (dp) down Represents the submerging depth sequence, dp up Representing a floating depth sequence;
then, carrying out equal-depth interpolation on different section data in the same group of data to obtain interpolation results of temperature, salinity and density of each section in the same depth interval, wherein the interpolation results are shown in the following formula:
and then, the temperature and salt density results of the sections with the same depth and different sections are averaged to obtain an average sequence, wherein the average sequence is shown in the following formula:
in the formula (11), j represents the cross-section number in the same group, and i represents the data number in the same cross-section.
6. The internal solitary wave parameter extraction algorithm based on the underwater glider as claimed in claim 5, wherein: in the step 3, the euclidean distance between each profile data and the average data is compared in the same depth interval, and the profile with the largest euclidean distance is selected as the suspicious sequence to be analyzed in the next step, wherein the suspicious sequence is represented by the following formula:
in the formula (12): d (D) Eucl (A, B) representing Euclidean distance calculations for sequences A and B, the specific calculation formulas being not shown to the right of the equation;a density sequence representing the jth cross section calculated by Newton's interpolation method of the measured density sequence according to formula (10)>Representing the average density sequence of the group;
the suspicious section is analyzed to find the maximum value diff of the difference diff between the equal close face and the average equal close face max Its corresponding depth dp md Finally, only extracting the profile data with the equal-density surface difference value larger than 25m and the maximum depth difference value larger than 20m to perform the next analysis, and outputting the machine number N of the suspicious sequence M Cross section number N P Equal-surface-to-average equal-surface maximum difference diff max Maximum difference depth dp md Floating frequency N, average depth intervalEqual depth average Density->Upper and lower layer thickness h 1 、h 2 Density ρ of upper and lower layers 1 、ρ 2 ;
Based on the output data of the suspicious sequence, the suspicious sequence is subjected to the next step of analysis: firstly, local water depth data are found according to the space coordinates of the suspicious section, and then the buoyancy frequency is calculated according to the measured density data, wherein the buoyancy frequency is shown in the following formula:
in the formula (13): g represents gravitational acceleration, ρ represents sea water density;
finding the depth with the greatest buoyancy frequency as the depth of the density jump layerDegree d pyc The maximum diff of the density difference appears in the previous analysis max Corresponding depth d md Substituting formula (14), and estimating the maximum internal solitary wave amplitude at the density jump layer through linear interpolation or other interpolation modes:
in formula (14): a represents amplitude, diff max Represents the maximum value of the density difference, d md Represents the depth of occurrence of the maximum value of the density difference, d tot Represents the total water depth d pyc Indicating the depth of the dense jump.
7. The internal solitary wave parameter extraction algorithm based on an underwater glider as claimed in claim 6, wherein: in the step 4, according to the thickness of the upper and lower layers and the amplitude of the internal solitary wave, selecting a proper internal solitary wave theory to calculate the characteristic parameters of the internal solitary wave, selecting a proper internal solitary wave theory to reconstruct the temperature salt profile at the occurrence time of the internal solitary wave, wherein the amplitude is calculated in a linear fitting mode along the change form of the depth or in an exponential fitting mode according to the actual situation, so as to form an equal-density surface change delta P caused by the internal solitary wave, and then the equal-density surface change delta P is matched with the initial density profile P 0 And combining to obtain density profile data which is finally output and contains the influence of the internal solitary wave on the isopipe, wherein the density profile data is shown in the following formula:
P=P 0 +ΔP (15)
in formula (15): p represents the density profile of the output, P 0 Representing the raw density profile, Δp represents the calculated intra-solitary wave-induced isopycnic face change according to the algorithm.
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