A global ocean gravity field model construction system and method with two types of inversion methods elastically configured

Abstract

The present application provides a system and method for constructing a global ocean gravity field model with two types of inversion methods elastically configured. The system reads in altimetry data and removes outliers; removes the reference geoid height model and the average sea surface dynamic terrain model to obtain satellite altimetry data for inversion; sets a weighting function for the fusion of the two types of ocean gravity field inversion methods, establishes a global elastic configuration strategy for the two types of inversion methods, and divides the inversion areas of the two types of inversion methods; inverts the ocean gravity field of the specified sea area based on the vertical deviation method and the geoid height method respectively; performs global elastic fusion of the regional ocean gravity fields obtained by the two types of inversion methods according to the fusion weight factors set by the global elastic configuration strategy; restores the reference gravity field model to the fused global ocean gravity field, and generates a global high-precision ocean gravity field model. The advantages of the present application are: it effectively integrates the advantages of the two types of inversion methods, the geoid height method and the vertical deviation method.

Description

Technical Field

[0001] The present application belongs to the field of ocean remote sensing mapping, and specifically relates to a global ocean gravity field model construction system and method with two types of inversion methods elastically configured. Background Art

[0002] Radar altimeter is an important active microwave remote sensor, which is carried on ocean remote sensing satellites. It transmits radar pulse signals to the sea surface and receives echo signals to obtain ocean observation data such as sea surface height (SSH), effective wave height, and wind speed. Gravity-related parameters such as ocean geoid and vertical deviation can be extracted from satellite altimeter SSH data, and the ocean gravity field can be further inverted. Satellite altimeter has a fast global coverage capability, can obtain global ocean gravity field information from space on a large scale, and can carry out repeated measurements. Compared with traditional gravity detection methods (such as ship measurement and aviation), satellite altimeter can complete the workload of the past century in a few months; compared with gravity satellites, satellite altimeter can detect short-wave ocean gravity field information with higher resolution. Therefore, satellite altimeter is currently the most effective means to obtain high-precision global ocean short-wave gravity field.

[0003] The geoid height method and the vertical deviation method are two mainstream methods for inverting the ocean gravity field based on satellite altimetry data. They have advantages in different types of sea areas. The geoid height method has better robustness, especially in nearshore, shallow water and sea areas with complex sea conditions such as those with significant influence of ocean circulation, and is less affected by noise interference; while the vertical deviation method has a more sensitive gravity field signal detection capability and has good performance in open sea areas, especially in areas with drastic changes in seabed topography. The most representative global ocean gravity field models in the world today are the series of ocean gravity field models of the Scripps Institution of Oceanography (SIO) in the United States and the series of ocean gravity field models constructed by the Technical University of Denmark (DTU). The SIO series of models are based on the vertical deviation method, and the DTU series of models use the geoid height method. At present, the construction methods of the global ocean gravity field model all use a single inversion method, which does not give full play to the advantages of the two inversion methods of the geoid height method and the vertical deviation method, and it is difficult to provide high-precision ocean gravity field information in complex sea areas around the world. Summary of the invention

[0004] The purpose of this application is to overcome the defect that the existing global ocean gravity field models are constructed using a single inversion method and are difficult to provide high-precision ocean gravity field information in complex sea areas around the world.

[0005] In order to achieve the above objectives, the present application proposes a global ocean gravity field model construction system with two types of inversion methods elastically configured, characterized in that the system comprises:

[0006] Satellite altimetry data preprocessing module: used to edit and control the quality of satellite altimetry data, remove invalid data and outliers, remove the reference model geoid height and ocean average dynamic topography from the sea surface height, and obtain the satellite survey line sea surface height data for inversion;

[0007] Elastic configuration module of gravity field inversion method: used to flexibly configure the ocean gravity field inversion method for different types of sea areas around the world. Based on the inversion mechanism of the geoid height method and the vertical deviation method, a weighted function is set for the fusion of the two types of ocean gravity field inversion methods, and a global elastic configuration strategy for the two types of inversion methods is established. The best applicable scenarios of the two types of methods are evaluated by examining the offshore distance, water depth, and seabed topographic characteristic parameters, and the inversion areas of the two types of inversion methods are divided;

[0008] Vertical deviation method inversion module: used to perform differential processing on the sea surface height data of the satellite survey line in the specified sea area to calculate the sea surface height slope, obtain the vertical deviation grid data by solving the vertical deviation component, and then invert the ocean gravity field of the specified sea area based on the vertical deviation method;

[0009] Geoid height inversion module: used to perform cross-point adjustment on the sea surface height data of the satellite survey line in the specified sea area, obtain the geoid height grid data through gridding processing, and then invert the ocean gravity field of the specified sea area based on the geoid height method;

[0010] Ocean gravity field model construction module: It is used to fuse the global elasticity of the regional ocean gravity field obtained by the two types of inversion methods according to the fusion weighted function of the global elastic configuration strategy of the ocean gravity field inversion method, and restore the reference gravity field model corresponding to the reference geoid height model removed above to construct the global ocean gravity field model.

[0011] As an improvement of the above system, the processing process of the satellite altimetry data preprocessing module includes:

[0012] Step A1: Data editing and quality control of satellite altimetry data are performed based on latitude and longitude information, sea surface height effective value range, and sea and land mask information, and invalid data and outliers are eliminated;

[0013] Step A2: Use the longitude and latitude information to interpolate to the corresponding position of the satellite altimetry data, and remove the reference model geoid height and mean dynamic terrain from the sea surface high:

[0014] ΔN=SSH-MDT-N ref

[0015] Where ΔN is the residual height used for subsequent inversion; SSH is the sea surface height obtained by satellite altimetry; MDT is the height value of the mean dynamic terrain model; N ref is the reference model geoid height.

[0016] As an improvement of the above system, the processing process of the elastic configuration module of the gravity field inversion method includes:

[0017] Step B1: Based on the inversion mechanism of the geoid height method and the vertical deviation method and combined with the offshore distance, water depth and seabed topography characteristic parameters, a weighting function is set for the fusion of the two types of ocean gravity field inversion methods, and a global elastic configuration strategy for the two types of ocean gravity field inversion methods is established:

[0018]

[0019] P DOV =1-P GEOID

[0020] Among them, P DOV and P GEOID They represent the fusion weight factors of the vertical deviation method and the geoid height method respectively; x represents the offshore distance or water depth of the gravity field position to be determined; x R Indicates the starting point of the nearshore or shallow water side of the fusion area of ​​the two types of ocean gravity field inversion methods; x Q represents the half width of the fusion area of ​​the two types of ocean gravity field inversion methods; x R +x Q It represents the center point of the fusion area of ​​the two types of ocean gravity field inversion methods. The fusion weight factors of the vertical deviation method and the geoid height method at this point are equal, both 1 / 2;

[0021] At 0≤x <x R In the range of x ≥ x, the geoid height method is used completely; R +2*x Q In the range of x, the vertical line deviation method is fully adopted; R ≤x <x R +2*x Q In the range, two types of ocean gravity field inversion methods are weighted fused;

[0022] Step B2: According to the global elastic configuration strategy of the ocean gravity field inversion method, the best applicable scenarios of the two methods are evaluated by examining the offshore distance, water depth and seabed topography characteristic parameters, that is, determining the best x under different investigation parameters. R and x Q , divide the inversion areas of the two methods: geoid height method and vertical deviation method.

[0023] As an improvement of the above system, the processing process of the vertical deviation method inversion module includes:

[0024] Step C1: Perform differential processing on the sea surface height data of the satellite altimeter in the specified sea area to calculate the sea surface slope information of the survey line, including time tdov , longitude λ dov , latitude φ dov , slope ε dov 、azimuth az dov and precision σ dov :

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032] Among them, t i , t j ,λ i ,λ j , h i ,h j Represents the time, longitude, latitude and sea level of two adjacent points i and j respectively; Re is the average radius of the earth; Respectively represent the accuracy of two adjacent points i and j;

[0033] Step C2: The sea surface high slope data near the grid point to be determined is solved by the vertical deviation component to obtain the vertical deviation grid data;

[0034] The observation equation for the average value of the sea surface slope and vertical deviation component is:

[0035]

[0036] Among them, ε k 、v k and α k are the slope, residual and azimuth of the kth observation point respectively; n is the number of sea surface slope points; and is the average value of the meridian component and the meridian component of the grid point;

[0037] According to the least squares principle, the meridian component and the zenithal component of the vertical deviation grid are solved;

[0038] Step C3: The solved vertical deviation grid data is used to invert the ocean gravity field of the specified sea area based on the vertical deviation method.

[0039] As an improvement of the above system, the processing process of the geoid height inversion module includes:

[0040] Step D1: Determine the intersection position of the sea surface height data of the satellite survey line in the specified sea area, perform adjustment based on the least squares principle, and remove orbit errors and time-varying noise;

[0041] Step D2: Gridding the adjusted sea level height data of the survey line to obtain geoid height grid data;

[0042] Step D3: Invert the geoid height grid data to obtain the ocean gravity field of the specified sea area based on the geoid height method.

[0043] As an improvement of the above system, the processing process of the ocean gravity field model construction module includes:

[0044] Step E1: According to the fusion weighting function set by the global elastic configuration strategy of the ocean gravity field inversion method, the regional ocean gravity fields obtained by the two types of inversion methods are globally elastically fused;

[0045] The expression of the global elastic fusion of the ocean gravity field inverted by the two methods is:

[0046] Δg COM =P DOV *Δg DOV +P GEOID *Δg GEOID

[0047] Where, Δg COM Indicates the gravity value obtained by fusion; Δg DOV and Δg GEOID They represent the ocean gravity value inverted from the vertical deviation and the ocean gravity value inverted from the geoid height. The default value of the uncalculated grid point gravity is 0; P DOV and P GEOID They represent the fusion weight factors of the vertical deviation method and the geoid height method respectively;

[0048] Step E2: restoring the reference gravity field model corresponding to the removed reference geoid height model to the fused global ocean gravity field to generate a global high-precision ocean gravity field model;

[0049] The global ocean gravity field model expression is:

[0050] g=Δg COM +g REF

[0051] Among them, g is the final ocean gravity field model; g REF is the reference gravity field model.

[0052] The present application also provides a method for constructing a global ocean gravity field model with two types of inversion methods elastically configured, which is implemented based on the above system and includes:

[0053] Step 1) read the altimetry data of the satellite radar altimeter, edit the data and remove abnormal values ​​in the altimetry data;

[0054] Step 2) removing the reference geoid height model and the average sea surface dynamic terrain model from the sea surface high altitude to obtain satellite altimetry data for inversion;

[0055] Step 3) elastically configure the ocean gravity field inversion methods for different types of sea areas around the world. Based on the inversion mechanism of the geoid height method and the vertical deviation method, a weighting function for the fusion of the two types of ocean gravity field inversion methods is set, and a global elastic configuration strategy for the two types of inversion methods is established. The best applicable scenarios of the two types of methods are evaluated by examining the offshore distance, water depth and seabed topographic characteristic parameters, and the inversion areas of the two types of inversion methods are divided;

[0056] Step 4) performing differential processing on the satellite altimetry data of the designated sea area to calculate the sea surface height slope, and solving the vertical deviation component information, and then inverting the ocean gravity field of the designated sea area based on the inverse Vening-Meinesz method;

[0057] The sea surface height intersection point adjustment is performed on the satellite altimetry data of the designated sea area, the geoid height grid data is calculated, and then the ocean gravity field of the designated sea area is inverted based on the inverse STOKES method;

[0058] Step 5) According to the fusion weight factor set by the global elastic configuration strategy of the ocean gravity field inversion method, the regional ocean gravity fields obtained by the two types of inversion methods are globally elastically fused;

[0059] Step 6) Restoring the reference gravity field model corresponding to the removed reference geoid height model to the fused global ocean gravity field to generate a global high-precision ocean gravity field model.

[0060] Compared with the prior art, the advantages of this application are:

[0061] 1. This application is the first to establish a global high-precision ocean gravity field model construction system with elastic configuration of the vertical deviation method and the geoid height method for complex sea areas.

[0062] 2. The global ocean gravity field model construction method proposed in this application can flexibly configure ocean gravity field inversion methods for different types of sea areas around the world, effectively integrating the advantages of the two inversion methods of geoid height method and vertical deviation method, and obtaining high-precision ocean gravity field information for complex sea areas around the world. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 Shown is the structure diagram of the global ocean gravity field model construction system with two types of elastic configurations of inversion methods;

[0064] Figure 2 Shown are schematic diagrams of elastic configuration strategies for two types of inversion methods;

[0065] Figure 3 Shown is a flow chart of the global ocean gravity field model construction method with two types of elastic configurations of inversion methods. DETAILED DESCRIPTION

[0066] The technical solution of the present application is described in detail below with reference to the accompanying drawings.

[0067] The global ocean gravity field model construction system and method for elastically configuring two types of inversion methods proposed in this application are not only used for radar altimeters, but also suitable for laser altimeters. By elastically configuring the ocean gravity field inversion method for different types of sea areas around the world, the advantages of the two types of inversion methods, the geoid height method and the vertical deviation method, are effectively integrated to obtain high-precision ocean gravity field information in complex sea areas around the world.

[0068] Example 1

[0069] like Figure 1 As shown, the present application proposes a global ocean gravity field model construction system with two types of inversion methods flexibly configured, including a satellite altimetry data preprocessing module, a gravity field inversion method elastic configuration module, a plumb line deviation method inversion module, a geoid height method inversion module and an ocean gravity field model construction module.

[0070] The design of each module is as follows:

[0071] 1. Satellite altimetry data preprocessing module: used to edit and quality control satellite altimetry data, remove invalid data and outliers, remove the reference model geoid height and ocean average dynamic topography from the sea surface height, and obtain the satellite survey line sea surface height data (time, longitude, latitude, altitude) for inversion;

[0072] The processing process of the satellite altimetry data preprocessing module includes:

[0073] Step 1: Edit the altimetry data; edit and quality control the satellite altimetry data according to the latitude and longitude information, the effective value range of the sea surface height, and the sea and land mask information, and remove invalid data and outliers;

[0074] Step 2: Remove the reference model; use the longitude and latitude information to interpolate to the corresponding position of the satellite altimetry data, and remove the EGM2008 reference model geoid height and mean dynamic terrain from the sea surface high.

[0075] ΔN=SSH-MDT-N ref

[0076] Where ΔN is the residual height used for subsequent inversion; SSH is the sea surface height obtained by satellite altimetry; MDT is the height value of the mean dynamic terrain model; N ref is the reference model geoid height.

[0077] 2. Elastic configuration module of gravity field inversion method: It is used to flexibly configure the ocean gravity field inversion method for different types of sea areas around the world. Based on the inversion mechanism of the geoid height method and the vertical deviation method, a weighted function is set for the fusion of the two types of ocean gravity field inversion methods, and a global elastic configuration strategy for the two types of inversion methods is established. The offshore distance, water depth, and seabed terrain characteristic parameters are examined to evaluate the best applicable scenarios of the two types of methods, and the inversion areas of the two types of inversion methods are divided;

[0078] The processing of the elastic configuration module of the gravity field inversion method includes:

[0079] Step 1: Establish a configuration strategy; Based on the inversion mechanism of the geoid height method and the vertical deviation method and combined with the offshore distance, water depth, and seabed topography characteristic parameters, set a weighting function for the fusion of the two types of ocean gravity field inversion methods, and establish a global elastic configuration strategy for the two types of ocean gravity field inversion methods, such as Figure 2 As shown;

[0080]

[0081] P DOV =1-P GEOID

[0082] Among them, P DOV and P GEOID They represent the fusion weight factors of the vertical deviation method and the geoid height method respectively. ; x represents the offshore distance or water depth of the gravity field position to be determined; x R Indicates the starting point of the nearshore or shallow water side of the fusion area of ​​the two types of ocean gravity field inversion methods; x Q represents the half width of the fusion area of ​​the two types of ocean gravity field inversion methods; x R +x Q It represents the center point of the fusion area of ​​the two types of ocean gravity field inversion methods. The fusion weight factors of the vertical deviation method and the geoid height method at this point are equal, both 1 / 2.

[0083] In nearshore and shallow water areas, that is, 0≤x <x R Within the range, the geoid height method is fully adopted; in the open sea and deep sea areas, that is, x ≥ x R +2*x Q In the range, the vertical line deviation method is fully adopted; in the intermediate transition area, that is, x R ≤x <x R +2*x Q Within this range, two types of ocean gravity field inversion methods are weighted fused.

[0084] Step 2: Divide the inversion area; according to the global elastic configuration strategy of the ocean gravity field inversion method, examine the offshore distance, water depth, and seabed topography characteristic parameters to evaluate the best applicable scenarios of the two methods (determine the best x under different investigation parameters) R and x Q ), divide the inversion areas of the two methods: the geoid height method and the vertical deviation method.

[0085] 3. Vertical deviation method inversion module: used to perform differential processing on the sea surface height data (time, longitude, latitude, height) of the satellite altimeter measurement line in the specified sea area to calculate the sea surface height slope, and obtain the vertical deviation grid data (longitude, latitude, meridian component, and meridian component) by solving the vertical deviation component, and then invert the ocean gravity field of the specified sea area based on the vertical deviation method;

[0086] The processing of the vertical deviation method inversion module includes:

[0087] Step 1: Calculate the sea surface height slope of the survey line; perform differential processing on the sea surface height data (time, longitude, latitude, altitude) of the satellite altimeter in the specified sea area to calculate the sea surface slope information (time, longitude, latitude, slope, azimuth, accuracy) of the survey line;

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] Where, t i , t j ,λ i ,λ j , h j ,h i Represents the time, longitude, latitude and sea level of two adjacent points (point i and point j); Re is the average radius of the earth; Δλ=(λ j -λ i ); Respectively represent the accuracy of two adjacent points. ( Can be a fixed value assigned by external evaluation or calculated based on altimeter data)

[0096] Step 2: Calculate the vertical deviation component; it is used to calculate the sea surface high slope data near the grid point to be determined through the vertical deviation component to obtain the vertical deviation grid data (longitude, latitude, meridian component, and meridian component).

[0097] If there are multiple height measurement data within a certain sea area near the grid point, the observation equation for the average value of the sea surface slope and the vertical deviation component is:

[0098]

[0099] In the formula, ε k , ν k and α k are the slope, residual and azimuth of the kth observation point respectively; n is the number of sea surface slope points; and It is the average value of the meridian component and the meridian component of the grid point.

[0100] According to the basic principle of least squares, the meridian component and the meridian component of the vertical deviation grid are solved.

[0101] Step 3: Invert the ocean gravity field; use the solved vertical deviation grid data (longitude, latitude, meridian component, and meridian component) to invert the ocean gravity field of the specified sea area based on the vertical deviation method.

[0102] The discrete expression of the inverse Vening-Meinesz formula for inverting gravity anomalies from the vertical deviation grid is:

[0103]

[0104] In the formula, is the gravity anomaly of the grid point p to be determined; γ0 is the average normal gravity value of the earth; and are the minimum and maximum latitudes of the calculation area; α qp ξ is the azimuth from the mobile grid point q to the grid point p in the calculation area; qand η q are the north-south and east-west components of the vertical deviation of the mobile grid point q in the calculation area, respectively; is the latitude of the mobile grid point q in the calculation area; and Δλ are the grid spacings in latitude and longitude; F1 and are the one-dimensional Fourier transform and inverse transform respectively. H' is the derivative of the kernel function H, expressed as

[0105]

[0106]

[0107] 4. Geoid height inversion module: used to perform cross-point adjustment on the sea surface height data (time, longitude, latitude, height) of the satellite altimeter in the specified sea area, obtain the geoid height grid data (longitude, latitude, geoid height) through gridding processing, and then invert the ocean gravity field of the specified sea area based on the geoid height method;

[0108] The processing of the geoid height inversion module includes:

[0109] Step 1: Intersection point adjustment: Determine the intersection point position based on the sea surface height data (time, longitude, latitude, and altitude) of the satellite altimeter in the specified sea area, and perform adjustment based on the least squares principle to remove orbital errors and time-varying noise;

[0110] Step 2: Gridding of geoid height: Gridding the sea level height data of the survey line after adjustment to obtain gridded geoid height data (longitude, latitude, geoid height);

[0111] Step 3: Invert the ocean gravity field; use the solved geoid height grid data to invert the ocean gravity field of the specified sea area based on the geoid height method.

[0112] The discrete expression of the inverse Stokes formula for deriving gravity anomaly from the geoid height grid is:

[0113]

[0114] In the formula, is the gravity anomaly of the grid point p to be determined; γ0 is the average normal gravity value of the earth; R is the average radius of the earth; is the geoid height of the grid point p to be determined; and λ q are the latitude and longitude of the mobile grid point q in the calculation area, respectively; and They are the minimum and maximum latitudes of the calculation area respectively; and Δλ are the grid spacings in latitude and longitude; F1 and are the one-dimensional FFT forward transform and inverse transform operators, and the kernel function for:

[0115]

[0116] 5. Ocean gravity field model construction module: It is used to fuse the global elasticity of the regional ocean gravity field obtained by the two types of inversion methods according to the fusion weighting function of the global elastic configuration strategy of the ocean gravity field inversion method, and restore the reference gravity field model corresponding to the above-mentioned removed EGM2008 reference geoid height model to construct a global high-precision ocean gravity field model;

[0117] The processing of the ocean gravity field model building module includes:

[0118] Step 1: Global fusion of regional ocean gravity fields; according to the fusion weighting function set by the global elastic configuration strategy of the ocean gravity field inversion method, the regional ocean gravity fields obtained by the two types of inversion methods are globally elastically fused.

[0119] The expression of the global elastic fusion of the ocean gravity field inverted by the two methods is:

[0120] ΔG COM =P DOV *Δg DOV +P GEOID Δg GEOID

[0121] Where, Δg COM Indicates the gravity value obtained by fusion; Δg DOV and Δg GEOID They represent the ocean gravity value inverted from the vertical deviation and the ocean gravity value inverted from the geoid height. The default value of the uncalculated grid point gravity is 0; P DOV and P GEOID Represents the fusion weight factor of the two types of ocean gravity field inversion methods, which is set by the global elastic configuration strategy.

[0122] Step 2: Restore the reference gravity field model; restore the reference gravity field model corresponding to the removed reference geoid height model to the fused global ocean gravity field to generate a global high-precision ocean gravity field model.

[0123] The global ocean gravity field model expression is:

[0124] g=Δg COM +g REF

[0125] Where g is the final ocean gravity field model; g REF is the reference gravity field model.

[0126] Example 2

[0127] like Figure 3 As shown, the present application also proposes a method for constructing a global ocean gravity field model with two types of inversion methods elastically configured, which is implemented based on the above system and includes:

[0128] Step 1) read the altimetry data of the satellite radar altimeter, edit the data and remove abnormal values ​​in the altimetry data;

[0129] Step 2) The satellite altimetry data preprocessing module removes the EGM2008 reference geoid height model and the mean sea surface dynamic terrain model from the sea surface height to obtain the satellite altimetry data (time, longitude, latitude, sea surface height) for inversion;

[0130] Step 3) The gravity field inversion method elastic configuration module flexibly configures the ocean gravity field inversion method for different types of sea areas around the world. Based on the inversion mechanism of the geoid height method and the vertical deviation method, a weighting function for the fusion of the two types of ocean gravity field inversion methods is set, and a global elastic configuration strategy for the two types of inversion methods is established. The offshore distance, water depth, and seabed topographic characteristic parameters are examined to evaluate the best applicable scenarios of the two types of methods, and the inversion areas of the two types of inversion methods are divided;

[0131] Step 4) The vertical deviation method inversion module performs differential processing on the satellite altimetry data (time, longitude, latitude, sea surface height) of the specified sea area to calculate the sea surface height slope, and solves the vertical deviation component information (longitude, latitude, meridian component, and meridian component), and then inverts the ocean gravity field of the specified sea area based on the inverse Vening-Meinesz method (IVM);

[0132] Step 5) The geoid height inversion module performs sea surface height intersection adjustment on the satellite altimetry data (time, longitude, latitude, sea surface height) of the specified sea area, calculates the geoid height grid data (longitude, latitude, geoid height), and then inverts the ocean gravity field of the specified sea area based on the inverse STOKES method (ISM);

[0133] Step 6) Global fusion of regional ocean gravity fields; the ocean gravity field model construction module performs global elastic fusion of the regional ocean gravity fields obtained by the two types of inversion methods according to the fusion weight factor set by the global elastic configuration strategy of the ocean gravity field inversion method;

[0134] Step 7) Restoring the EGM2008 model; the ocean gravity field model construction module restores the EGM2008 reference gravity field model corresponding to the removed reference geoid height model to the fused global ocean gravity field, generating a global high-precision ocean gravity field model.

[0135] The present application may also provide a computer device, comprising: at least one processor, a memory, at least one network interface and a user interface. The various components in the device are coupled together through a bus system. It is understood that the bus system is used to achieve connection and communication between these components. In addition to the data bus, the bus system also includes a power bus, a control bus and a status signal bus.

[0136] The user interface may include a display, a keyboard or a pointing device, such as a mouse, a trackball, a touch pad or a touch screen.

[0137] It is understood that the memory in the embodiments disclosed in the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus random access memory (DRRAM). The memories described herein are intended to include, but are not limited to, these and any other suitable types of memories.

[0138] In some embodiments, the memory stores the following elements, executable modules or data structures, or a subset thereof, or an extended set thereof: an operating system and applications.

[0139] The operating system includes various system programs, such as a framework layer, a core library layer, a driver layer, etc., which are used to implement various basic services and process hardware-based tasks. The application includes various application programs, such as a media player (Media Player), a browser (Browser), etc., which are used to implement various application services. The program for implementing the method of the embodiment of the present disclosure can be included in the application.

[0140] In the above embodiment, the processor may also call a program or instruction stored in the memory, specifically, a program or instruction stored in an application program, and is used to:

[0141] Execute the steps of the above method.

[0142] The above method can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor may be a general processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The above-disclosed methods, steps and logic block diagrams can be implemented or executed. The general processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the above-disclosed method can be directly embodied as a hardware decoding processor to execute, or the hardware and software modules in the decoding processor are combined to execute. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0143] It is understood that the embodiments described in the present application can be implemented by hardware, software, firmware, middleware, microcode or a combination thereof. For hardware implementation, the processing unit can be implemented in one or more application specific integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), field programmable gate arrays (FPGA), general-purpose processors, controllers, microcontrollers, microprocessors, other electronic units for performing the functions described in the present application or a combination thereof.

[0144] For software implementation, the technology of the present application can be implemented by executing the functional modules (such as procedures, functions, etc.) of the present application. The software code can be stored in a memory and executed by a processor. The memory can be implemented in the processor or outside the processor.

[0145] The present application may also provide a non-volatile storage medium for storing a computer program. When the computer program is executed by a processor, each step in the above method embodiment can be implemented.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application is described in detail with reference to the embodiments, a person skilled in the art should understand that any modification or equivalent replacement of the technical solution of the present application does not depart from the spirit and scope of the technical solution of the present application and should be included in the scope of the claims of the present application.

Claims

1. A global ocean gravity field model construction system with two types of inversion methods and elastic configuration, characterized in that: The system comprises: Satellite altimetry data preprocessing module: used to edit and control the quality of satellite altimetry data, remove invalid data and outliers, remove the reference model geoid height and ocean average dynamic topography from the sea surface height, and obtain the satellite survey line sea surface height data for inversion; Elastic configuration module of gravity field inversion method: used to flexibly configure the ocean gravity field inversion method for different types of sea areas around the world. Based on the inversion mechanism of the geoid height method and the vertical deviation method, a weighted function is set for the fusion of the two types of ocean gravity field inversion methods, and a global elastic configuration strategy for the two types of inversion methods is established. The best applicable scenarios of the two types of methods are evaluated by examining the offshore distance, water depth, and seabed topographic characteristic parameters, and the inversion areas of the two types of inversion methods are divided; Vertical deviation method inversion module: used to perform differential processing on the sea surface height data of the satellite survey line in the specified sea area to calculate the sea surface height slope, obtain the vertical deviation grid data by solving the vertical deviation component, and then invert the ocean gravity field of the specified sea area based on the vertical deviation method; Geoid height inversion module: used to perform cross-point adjustment on the sea surface height data of the satellite survey line in the specified sea area, obtain the geoid height grid data through gridding processing, and then invert the ocean gravity field of the specified sea area based on the geoid height method; and Ocean gravity field model construction module: It is used to fuse the global elasticity of the regional ocean gravity field obtained by the two types of inversion methods according to the fusion weighted function of the global elastic configuration strategy of the ocean gravity field inversion method, and restore the reference gravity field model corresponding to the removed reference model geoid height to construct a global ocean gravity field model.

2. The global ocean gravity field model construction system with two types of inversion methods elastically configured according to claim 1 is characterized in that: The processing process of the satellite altimetry data preprocessing module includes: Step A1: Data editing and quality control of satellite altimetry data are performed based on latitude and longitude information, effective range of sea surface height, and sea and land mask information, and invalid data and outliers are eliminated; Step A2: Use the longitude and latitude information to interpolate to the corresponding position of the satellite altimetry data, and remove the reference model geoid height and mean dynamic terrain from the sea surface high: ΔN=SSH-MDT-N ref Where ΔN is the residual height used for subsequent inversion; SSH is the sea surface height obtained by satellite altimetry; MDT is the height value of the mean dynamic terrain model; N ref is the reference model geoid height.

3. The global ocean gravity field model construction system with two types of inversion methods elastically configured according to claim 1 is characterized in that: The processing process of the elastic configuration module of the gravity field inversion method includes: Step B1: Based on the inversion mechanism of the geoid height method and the vertical deviation method and combined with the offshore distance, water depth and seabed topography characteristic parameters, a weighting function is set for the fusion of the two types of ocean gravity field inversion methods, and a global elastic configuration strategy for the two types of ocean gravity field inversion methods is established: P DOV =1-P GEOID Among them, P DOV and P GEOID They represent the fusion weight factors of the vertical deviation method and the geoid height method respectively; x represents the offshore distance or water depth of the gravity field position to be determined; x R Indicates the starting point of the nearshore or shallow water side of the fusion area of ​​the two types of ocean gravity field inversion methods; x Q represents the half width of the fusion area of ​​the two types of ocean gravity field inversion methods; x R +x Q It represents the center point of the fusion area of ​​the two types of ocean gravity field inversion methods. The fusion weight factors of the vertical deviation method and the geoid height method at this point are equal, both 1 / 2; At 0≤x <x R In the range of x ≥ x, the geoid height method is used completely; R +2*x Q In the range of x, the vertical line deviation method is used completely; R ≤x <x R +2*x Q In the range, two types of ocean gravity field inversion methods are weighted fused; Step B2: According to the global elastic configuration strategy of the ocean gravity field inversion method, the best applicable scenarios of the two methods are evaluated by examining the offshore distance, water depth and seabed topography characteristic parameters, that is, determining the best x under different investigation parameters. R and x Q , divide the inversion areas of the two methods: geoid height method and vertical deviation method.

4. The global ocean gravity field model construction system with two types of inversion methods elastically configured according to claim 1 is characterized in that: The processing process of the vertical deviation method inversion module includes: Step C1: Perform differential processing on the sea surface height data of the satellite altimeter in the specified sea area to calculate the sea surface slope information of the survey line, including time t dov , longitude λ dov ,latitude Slope ε dov 、azimuth az dov and precision σ dov : Among them, t i , t j ,λ i ,λ j , h i ,h j Represents the time, longitude, latitude and sea level of two adjacent points i and j respectively; Re is the average radius of the earth; Respectively represent the accuracy of two adjacent points i and j; Step C2: The sea surface high slope data near the grid point to be determined is solved by the vertical deviation component to obtain the vertical deviation grid data; The observation equation for the average value of the sea surface slope and vertical deviation component is: Among them, ε k 、v k and α k are the slope, residual and azimuth of the kth observation point respectively; n is the number of sea surface slope points; and is the average value of the meridian component and the meridian component of the grid point; According to the least squares principle, the meridian component and the zenithal component of the vertical deviation grid are solved; Step C3: The solved vertical deviation grid data is used to invert the ocean gravity field of the specified sea area based on the vertical deviation method.

5. The global ocean gravity field model construction system with two types of inversion methods elastically configured according to claim 1 is characterized in that: The processing process of the geoid height inversion module includes: Step D1: Determine the intersection position of the sea surface height data of the satellite survey line in the specified sea area, perform adjustment based on the least squares principle, and remove orbit errors and time-varying noise; Step D2: Gridding the adjusted sea level height data of the survey line to obtain geoid height grid data; Step D3: Invert the geoid height grid data to obtain the ocean gravity field of the specified sea area based on the geoid height method.

6. The global ocean gravity field model construction system with two types of inversion methods elastically configured according to claim 1 is characterized in that: The processing process of the ocean gravity field model construction module includes: Step E1: According to the fusion weighting function set by the global elastic configuration strategy of the ocean gravity field inversion method, the regional ocean gravity fields obtained by the two types of inversion methods are globally elastically fused; The expression of the global elastic fusion of the ocean gravity field inverted by the two methods is: Δg COM =P DOV *Δg DOV +p GEOID *Δg GEOID Where, Δg COM Indicates the gravity value obtained by fusion; Δg DOV and Δg GEOID They represent the ocean gravity value inverted from the vertical deviation and the ocean gravity value inverted from the geoid height. The default value of the uncalculated grid point gravity is 0; P DOV and P GEOID They represent the fusion weight factors of the vertical deviation method and the geoid height method respectively; Step E2: restoring the reference gravity field model corresponding to the removed reference model geoid height to the fused global ocean gravity field to generate a global high-precision ocean gravity field model; The global ocean gravity field model expression is: g=Δg COM +g REF Among them, g is the final ocean gravity field model; g REF is the reference gravity field model.

7. A method for constructing a global ocean gravity field model with two types of inversion methods elastically configured, based on the system of any one of claims 1 to 6, the method comprising: Step 1) read the altimetry data of the satellite radar altimeter, edit the data and remove abnormal values ​​in the altimetry data; Step 2) removing the reference geoid height model and the average sea surface dynamic terrain model from the sea surface high altitude to obtain satellite altimetry data for inversion; Step 3) elastically configure the ocean gravity field inversion methods for different types of sea areas around the world. Based on the inversion mechanism of the geoid height method and the vertical deviation method, a weighting function for the fusion of the two types of ocean gravity field inversion methods is set, and a global elastic configuration strategy for the two types of inversion methods is established. The best applicable scenarios of the two types of methods are evaluated by examining the offshore distance, water depth and seabed topographic characteristic parameters, and the inversion areas of the two types of inversion methods are divided; Step 4) performing differential processing on the satellite altimetry data of the designated sea area to calculate the sea surface height slope, and solving the vertical deviation component information, and then inverting the ocean gravity field of the designated sea area based on the inverse Vening-Meinesz method; The sea surface height intersection point adjustment is performed on the satellite altimetry data of the designated sea area, the geoid height grid data is calculated, and then the ocean gravity field of the designated sea area is inverted based on the inverse STOKES method; Step 5) According to the fusion weight factor set by the global elastic configuration strategy of the ocean gravity field inversion method, the regional ocean gravity fields obtained by the two types of inversion methods are globally elastically fused; Step 6) restore the reference gravity field model corresponding to the removed reference model geoid height to the fused global ocean gravity field to generate a global high-precision ocean gravity field model.

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