A method and system for evaluating the advantages of inverting seafloor terrain models using disturbance field elements

Abstract

The present invention discloses a method and system for evaluating the advantages of inverting a seabed topography model using a disturbance field element. The method comprises: step 1: determining the effective integral radius of the first-order tensor of the disturbance position and the second-order tensor of the disturbance position of the forward modeling of the sea depth; step 2: taking the effective integral radius determined in step 1 as the integral window radius, taking the sea depth of the target sea area grid as data input, and forward modeling the first-order tensor of the disturbance position and the second-order tensor of the disturbance position; step 3: taking the first-order tensor of the disturbance position and the second-order tensor of the disturbance position of the target sea area obtained in step 2 as input, using the GMT software "grdfft" command to calculate the power spectrum density of the first-order tensor of the disturbance position and the second-order tensor of the disturbance position, and then comparing the power spectrum density difference of the first-order tensor of the disturbance position and the second-order tensor of the disturbance position, respectively. The greater the power spectrum density, the richer the spectrum of the seabed topography information contained. The present invention has important reference value for broadening the selection range of seabed topography gravity data elements constructed according to sea surface gravity data.

Description

Technical Field

[0001] The invention belongs to the technical field of seabed topography inversion, and in particular relates to a method and system for evaluating the advantages of a seabed topography model inverted by a disturbance field element. Background Art

[0002] At present, the tide of the times of the global marine science and technology revolution is surging, and the "transparency" of marine cognition is becoming the forefront of international marine science and technology development. The mastery of key technologies for deep-sea entry, deep-sea exploration, and deep-sea development has become an important symbol of a maritime power. Marine observation capabilities are the foundation of marine scientific research, and improving marine observation capabilities is of great significance to the improvement of marine science and technology levels. As a basic means of observing and understanding the ocean, the seabed topography survey can play an irreplaceable role in the development of marine resources, the protection of marine ecological environment, marine science and technology innovation, and the maintenance of marine rights and interests. With the rapid development of satellite altimetry technology in recent decades, long-term, continuous, large-scale, and real-time in-situ marine observations have been achieved based on satellite-based measurement platforms, and massive, multi-generation, high-resolution, and high-precision satellite altimetry data have been accumulated. Scholars from various countries have restored and improved the high-quality gravity field information of the global ocean based on the continuously updated satellite altimetry data. The inversion of seabed topography based on ocean gravity information has become the main technical means for efficiently constructing global seabed topography.

[0003] In general, the data elements for constructing the seabed topography model using sea surface gravity data are still relatively simple, with the main data elements being gravity anomalies and vertical gradients of gravity anomalies. The feasibility analysis of constructing seabed topography using other gravity data elements is rarely involved. Studies have shown that the seabed topography restoration using sea surface gravity is mainly reflected in the enrichment and improvement of limited frequency band information of the seabed topography. Summary of the invention

[0004] The present invention aims at the problem that the input of gravity field elements for inverting seabed topography using satellite altimetry gravity data is relatively single, and provides a method and system for evaluating the advantages of inverting seabed topography models using disturbance field elements. By using the first-order tensor of disturbance potential and the second-order tensor of disturbance potential forward modeling of seabed topography data as data, the spectrum richness of seabed topography information contained in the first-order tensor of disturbance potential and the second-order tensor of disturbance potential is analyzed from the perspective of power spectrum density to evaluate the advantages of inverting seabed topography models using disturbance field elements, and expand the selection range of disturbance field element data for inverting seabed topography using sea surface gravity data.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a method for evaluating the advantages of inverting a seafloor terrain model using disturbance field elements, comprising:

[0007] Step 1: Determine the effective integration radius of the first-order tensor of the forward modeled disturbance potential and the second-order tensor of the disturbance potential;

[0008] Step 2: Taking the effective integration radius determined in step 1 as the integration window radius, taking the grid sea depth of the target sea area as data input, forward modeling the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential;

[0009] Step 3: Taking the first-order tensor and second-order tensor of the target sea area disturbance potential obtained in step 2 as input, use the GMT software "grdfft" command to calculate the power spectral density of the first-order tensor and second-order tensor of the target sea area disturbance potential, and then compare the differences in the power spectral density of the first-order tensor and second-order tensor of the disturbance potential. The larger the power spectral density, the richer the spectrum of the seabed topography information contained.

[0010] Furthermore, the step 1 comprises:

[0011] Select the sea surface research point, use the strict prismatic volume integral method, and continuously increase the integral radius until the forward modeling disturbance potential first-order tensor and the disturbance potential second-order tensor are in a convergent state. The integral radius at this time is taken as the effective integral radius:

[0012] The first-order tensor of the forward disturbance potential can be described as follows using the strict prismatic volume integral formula:

[0013]

[0014] in

[0015]

[0016] In the formula, and They represent the first-order tensors of the disturbance potential in the x, y and z directions of the ocean depth forward modeling; G is the earth's gravitational potential constant; ρ c and ρ w Represent the crust density and seawater density respectively; (i p ,j p ) is the location of the research point; (i, j) is the location of the flow point; h(i, j) is the corresponding sea depth of point (i, j); d is the depth of the seabed topography reference surface; l is the distance between the research point and the flow point; (x, y, z) is the coordinates of the flow point; S L and S B Indicates the number of points of the central area integral radius in the longitude and latitude directions; △x and △y respectively indicate the size of the grid along the longitude and latitude directions;

[0017] The second-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula:

[0018]

[0019] In the formula, They represent the second-order tensors of the disturbance potential in the xx, yy, zz, xy, xz, and yz directions of the ocean depth forward modeling respectively.

[0020] Furthermore, the step 2 includes: using equations (1) and (3) to forward model the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential.

[0021] Furthermore, in step 3, the calculation method of the power spectrum density can be described as:

[0022] PSD = 10·log 10 (P) (4)

[0023] Among them, PSD is power spectral density; P represents the energy of different wavelengths.

[0024] Another aspect of the present invention provides a disturbance field element inversion seabed terrain model advantage evaluation system, comprising:

[0025] An effective integration radius obtaining module is used to determine the effective integration radius of the first-order tensor of the forward modeled disturbance potential and the second-order tensor of the disturbance potential;

[0026] The forward modeling disturbance field element module is used to obtain the effective integration radius determined by the module as the integration window radius, and to forward model the first-order tensor of disturbance potential and the second-order tensor of disturbance potential using the grid sea depth of the target sea area as data input;

[0027] The power spectrum density calculation module is used to take the first-order tensor and the second-order tensor of the target sea area disturbance potential obtained by the forward disturbance module as input, use the GMT software "grdfft" command to calculate the power spectrum density of the first-order tensor and the second-order tensor of the disturbance potential of the target sea area, and then compare the differences in the power spectrum density of the first-order tensor and the second-order tensor of the disturbance potential. The larger the power spectrum density, the richer the spectrum of the seabed topography information contained.

[0028] Furthermore, the effective integral radius deriving module is specifically used for:

[0029] Select the sea surface research point, use the strict prismatic volume integral method, and continuously increase the integral radius until the forward modeling disturbance potential first-order tensor and the disturbance potential second-order tensor are in a convergent state. The integral radius at this time is taken as the effective integral radius:

[0030] The first-order tensor of the forward disturbance potential can be described as follows using the strict prismatic volume integral formula:

[0031]

[0032] in

[0033]

[0034] In the formula, and They represent the first-order tensors of the disturbance potential in the x, y and z directions of the ocean depth forward modeling; G is the earth's gravitational potential constant; ρ c and ρ w Represent the crust density and seawater density respectively; (i p ,j p ) is the location of the research point; (i, j) is the location of the flow point; h(i, j) is the corresponding sea depth of point (i, j); d is the depth of the seabed topography reference surface; l is the distance between the research point and the flow point; (x, y, z) is the coordinates of the flow point; S L and S B Indicates the number of points of the central area integral radius in the longitude and latitude directions; △x and △y respectively indicate the size of the grid along the longitude and latitude directions;

[0035] The second-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula:

[0036]

[0037] In the formula, They represent the second-order tensors of the disturbance potential in the xx, yy, zz, xy, xz, and yz directions of the ocean depth forward modeling respectively.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention is based on the forward recovery of the first-order tensor of disturbance potential and the second-order tensor of disturbance potential by seabed topography data, analyzes the spectral richness of the seabed topography information contained in the first-order tensor of disturbance potential and the second-order tensor of disturbance potential from the perspective of power spectral density, evaluates the advantages of inverting the seabed topography model with disturbance field elements, and further reveals the spectral characteristic connection between the seabed topography and the sea surface disturbance field elements, which has important reference value for broadening the selection range of seabed topography data elements constructed according to sea surface gravity data. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A basic flow chart of a method for evaluating the superiority of a disturbance field element inversion seabed terrain model according to an embodiment of the present invention;

[0041] Figure 2 This is an example diagram of the sea depth model of the target sea area;

[0042] Figure 3 This is a curve diagram showing the forward modeling results of the disturbance potential component at the example point changing with the terrain integral radius;

[0043] Figure 4 It is the power spectrum curve of the first-order tensor and the second-order tensor of the disturbance;

[0044] Figure 5The present invention is a schematic diagram of the architecture of a disturbance field element inversion seabed terrain model advantage evaluation system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments:

[0046] like Figure 1 As shown, a method for evaluating the advantages of inverting a seafloor topography model using a disturbance field element includes:

[0047] Step 101: determining the effective integration radius of the first-order tensor of the forward modeled disturbance potential and the second-order tensor of the disturbance potential;

[0048] Step S102: using the effective integration radius determined in step S101 as the integration window radius, taking the grid sea depth of the target sea area as data input, and forward modeling the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential;

[0049] Step S103: Taking the first-order tensor of the disturbance potential of the target sea area and the second-order tensor of the disturbance potential obtained in step S102 as input, use the GMT software "grdfft" command to calculate the power spectral density of the first-order tensor of the disturbance potential of the target sea area and the second-order tensor of the disturbance potential, and then compare the differences in the power spectral density of the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential, respectively. The larger the power spectral density, the richer the spectrum of the seabed topography information contained.

[0050] Furthermore, the step S101 includes:

[0051] Select the sea surface research point, use the strict prismatic volume integral method, and continuously increase the integral radius until the forward modeling disturbance potential first-order tensor and the disturbance potential second-order tensor are in a convergent state. The integral radius at this time is taken as the effective integral radius:

[0052] The first-order tensor of the forward disturbance potential can be described as follows using the strict prismatic volume integral formula:

[0053]

[0054] in

[0055]

[0056] In the formula, and They represent the first-order tensors of the disturbance potential in the x, y and z directions of the ocean depth forward modeling; G is the earth's gravitational potential constant; ρ c and ρ w Represent the crust density and seawater density respectively; (i p ,j p) is the location of the research point; (i, j) is the location of the flow point; h(i, j) is the corresponding sea depth of point (i, j); d is the depth of the seabed topography reference surface; l is the distance between the research point and the flow point; (x, y, z) is the coordinates of the flow point; S L and S B Indicates the number of points of the central area integral radius in the longitude and latitude directions; △x and △y respectively indicate the size of the grid along the longitude and latitude directions;

[0057] The second-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula:

[0058]

[0059] In the formula, They represent the second-order tensors of the disturbance potential in the xx, yy, zz, xy, xz, and yz directions of the ocean depth forward modeling respectively.

[0060] Furthermore, the step S102 includes: using equations (1) and (3) to forward model the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential.

[0061] Furthermore, in step S103, the calculation method of the power spectrum density can be described as:

[0062] PSD = 10·log 10 (P) (4)

[0063] Among them, PSD is power spectral density; P represents the energy of different wavelengths.

[0064] Specifically, the target sea area is 6°×6° (158°E~164°E, 19°N~25°N) in the western Pacific Ocean, S&SV19.1 is used as the seabed topography input data, and the rigorous prismatic volume integral method is used to forward model the first-order tensor and the second-order tensor of the disturbance potential. The spectral richness of the seabed topography information contained in the results is compared.

[0065] Step 1: Select the sea surface of the test area (21°59′30″N, 160°59′30″E) as a typical research point, and use the seafloor topography of the Western Pacific S&S V19.1 as input ( Figure 2 ), respectively, forward modeling the disturbance potential component results under different integration radius environments at the example points. The forward modeling results of the disturbance potential component at the example points change with the terrain integration radius as shown in the figure. Figure 3 Specifically, taking into account the validity of the disturbance field element forward modeling results and the richness of the forward modeling result data, the effective integration radius is set to 120.60 km.

[0066] Step 2: Take the effective integration radius of 120.60 km as the window radius, and get a total of 51076 sliding windows. Use equations (1) and (3) to calculate the first-order tensor and second-order tensor of the disturbance potential in each window in the target sea area.

[0067] Step 3: Use the GMT software “grdfft” command to process the first-order and second-order tensor results of the disturbance potential obtained in step 2, and use formula (4) to calculate the power spectrum density of the first-order and second-order tensor of the disturbance potential in the target sea area, and draw the power spectrum curves of the first-order and second-order tensors of the disturbance potential respectively. Figure 4 .

[0068] Figure 4 (a) shows that the medium- and long-wave topographic "component" contained in Tz is significantly higher than that in Tx and Ty. Figure 3 As shown in (b), the power spectrum curves of the various quantities of the disturbed gravity gradient are basically the same, among which Tzz contains significantly more medium- and long-wave topographic information than the other quantities. Therefore, it is recommended to focus on the first-order tensor Tz and the second-order tensor Tzz of the disturbed potential in the modeling of seafloor topography.

[0069] Based on the above embodiments, Figure 5 As shown, the present invention also proposes a disturbance field element inversion seabed terrain model advantage evaluation system, comprising:

[0070] An effective integration radius obtaining module 201 is used to determine the effective integration radius of the first-order tensor of the forward modeled disturbance potential and the second-order tensor of the disturbance potential;

[0071] The forward modeling disturbance field element module 202 is used to use the effective integration radius determined by the effective integration radius obtaining module as the integration window radius, and use the grid sea depth of the target sea area as data input to forward model the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential;

[0072] The power spectrum density calculation module 203 is used to use the first-order tensor of the disturbance potential of the target sea area and the second-order tensor of the disturbance potential obtained by the forward disturbance module as input, use the GMT software "grdfft" command to calculate the power spectrum density of the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential of the target sea area, and then compare the differences in the power spectrum density of the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential. The larger the power spectrum density, the richer the spectrum of the seabed topography information contained.

[0073] Furthermore, the effective integral radius obtaining module 201 is specifically used for:

[0074] Select the sea surface research point, use the strict prismatic volume integral method, and continuously increase the integral radius until the forward modeling disturbance potential first-order tensor and the disturbance potential second-order tensor are in a convergent state. The integral radius at this time is taken as the effective integral radius:

[0075] The first-order tensor of the forward disturbance potential can be described as follows using the strict prismatic volume integral formula:

[0076]

[0077] in

[0078]

[0079] In the formula, and They represent the first-order tensors of the disturbance potential in the x, y and z directions of the ocean depth forward modeling; G is the earth's gravitational potential constant; ρ c and ρ w Represent the crust density and seawater density respectively; (i p ,j p ) is the location of the research point; (i, j) is the location of the flow point; h(i, j) is the corresponding sea depth of point (i, j); d is the depth of the seabed topography reference surface; l is the distance between the research point and the flow point; (x, y, z) is the coordinates of the flow point; S L and S B Indicates the number of points of the central area integral radius in the longitude and latitude directions; △x and △y respectively indicate the size of the grid along the longitude and latitude directions;

[0080] The second-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula:

[0081]

[0082] In the formula, They represent the second-order tensors of the disturbance potential in the xx, yy, zz, xy, xz, and yz directions of the ocean depth forward modeling respectively.

[0083] Furthermore, the forward modeling disturbance module is also specifically used to: use equations (1) and (3) to forward model the first-order disturbance position tensor and the second-order disturbance position tensor.

[0084] Furthermore, in the power spectrum density calculation module, the calculation method of the power spectrum density can be described as:

[0085] PSD = 10·log 10 (P) (4)

[0086] Among them, PSD is power spectral density; P represents the energy of different wavelengths.

[0087] The present invention is based on the forward recovery of the first-order tensor of disturbance potential and the second-order tensor of disturbance potential by seabed topography data, analyzes the spectral richness of the seabed topography information contained in the first-order tensor of disturbance potential and the second-order tensor of disturbance potential from the perspective of power spectral density, evaluates the advantages of inverting the seabed topography model with disturbance field elements, and further reveals the spectral characteristic connection between the seabed topography and the sea surface disturbance field elements, which has important reference value for broadening the selection range of seabed topography data elements constructed according to sea surface gravity data.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for evaluating the advantages of inverting a seafloor topography model using a disturbance field element, characterized in that: include: Step 1: Determine the effective integration radius of the first-order tensor of the forward modeled disturbance potential and the second-order tensor of the disturbance potential; The step 1 comprises: Select the sea surface research point, use the strict prismatic volume integral method, and continuously increase the integral radius until the forward modeling disturbance potential first-order tensor and the disturbance potential second-order tensor are in a convergent state. The integral radius at this time is taken as the effective integral radius: The first-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula: in In the formula, and They represent the first-order tensors of the disturbance potential in the x, y and z directions of the ocean depth forward modeling; G is the earth's gravitational potential constant; ρ c and ρ w Represent the crust density and seawater density respectively; (i p ,j p ) is the location of the research point; (i, j) is the location of the flow point; h(i, j) is the corresponding sea depth of point (i, j); d is the depth of the seabed topography reference surface; l is the distance between the research point and the flow point; (x, y, z) is the coordinates of the flow point; S L and S B Indicates the number of points of the central area integral radius in the longitude and latitude directions; △x and △y respectively indicate the size of the grid along the longitude and latitude directions; The second-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula: In the formula, They represent the second-order tensors of disturbance potential in the directions of xx, yy, zz, xy, xz, and yz of the forward modeling of ocean depth respectively; Step 2: Taking the effective integration radius determined in step 1 as the integration window radius, taking the grid sea depth of the target sea area as data input, forward modeling the first-order tensor of disturbance potential and the second-order tensor of disturbance potential; The step 2 comprises: using equations (1) and (3) to forward model the first-order tensor of the disturbance potential and the second-order tensor of the disturbance potential; Step 3: Taking the first-order tensor and second-order tensor of the target sea area disturbance potential obtained in step 2 as input, use the GMT software "grdfft" command to calculate the power spectral density of the first-order tensor and second-order tensor of the target sea area disturbance potential, and then compare the power spectral density differences of the first-order tensor and second-order tensor of the disturbance potential. The larger the power spectral density, the richer the spectrum of the seabed topography information contained.

2. The method for evaluating the superiority of the seafloor terrain model inverted by disturbance field elements according to claim 1 is characterized in that: In step 3, the calculation method of power spectrum density can be described as: PSD=10·log 10 (P) (4) Among them, PSD is power spectral density; P represents the energy of different wavelengths.

3. A disturbance field element inversion seabed terrain model advantage evaluation system, characterized in that: include: An effective integration radius obtaining module is used to determine the effective integration radius of the first-order tensor of the forward modeled disturbance potential and the second-order tensor of the disturbance potential; The effective integral radius obtaining module is specifically used for: Select the sea surface research point, use the strict prismatic volume integral method, and continuously increase the integral radius until the forward modeling disturbance potential first-order tensor and the disturbance potential second-order tensor are in a convergent state. The integral radius at this time is taken as the effective integral radius: The first-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula: in In the formula, and They represent the first-order tensors of the disturbance potential in the x, y and z directions of the ocean depth forward modeling; G is the earth's gravitational potential constant; ρ c and ρ w Represent the crust density and seawater density respectively; (i p ,j p ) is the location of the research point; (i, j) is the location of the flow point; h(i, j) is the corresponding sea depth of point (i, j); d is the depth of the seabed topography reference surface; l is the distance between the research point and the flow point; (x, y, z) is the coordinates of the flow point; S L and S B Indicates the number of points of the central area integral radius in the longitude and latitude directions; △x and △y respectively indicate the size of the grid along the longitude and latitude directions; The second-order tensor of the forward disturbance potential can be described as follows using the strict prismatic integral formula: In the formula, They represent the second-order tensors of disturbance potential in the directions of xx, yy, zz, xy, xz, and yz of the forward modeling of ocean depth respectively; The forward modeling disturbance field element module is used to obtain the effective integration radius determined by the module as the integration window radius, and to forward model the first-order tensor of disturbance potential and the second-order tensor of disturbance potential using the grid sea depth of the target sea area as data input; The forward modeling disturbance field element module comprises: using equation (1) and equation (3) to forward model the first-order disturbance potential tensor and the second-order disturbance potential tensor; The power spectrum density calculation module is used to take the first-order tensor and the second-order tensor of the target sea area disturbance potential obtained by the forward disturbance module as input, use the GMT software "grdfft" command to calculate the power spectrum density of the first-order tensor and the second-order tensor of the disturbance potential of the target sea area, and then compare the power spectrum density differences of the first-order tensor and the second-order tensor of the disturbance potential. The larger the power spectrum density, the richer the spectrum of the seabed topography information contained.

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