A deep-sea suspended sediment facies fraction profile measuring device and method

Abstract

The application provides a deep-sea suspended sediment phase fraction profile measuring device and method, and the device comprises: a mounting assembly arranged in a water body along a water depth direction; a plurality of impedance measuring nodes arranged at intervals along the mounting assembly, each of which is provided with an electrode probe for contacting a seawater and suspended sediment mixed system; and a main control and power supply unit electrically connected with each impedance measuring node, which provides a multi-frequency alternating current excitation signal to each impedance measuring node, collects a multi-frequency electrical impedance data response signal returned by each node, and calculates a suspended sediment phase fraction at a position of each node according to the multi-frequency electrical impedance data response signal. The technical scheme is suitable for a seawater environment, can truly reflect vertical distribution characteristics of suspended sediments at the same time, and is suitable for a condition with a high particle content.

Description

Technical Field

[0001] This invention relates to the field of marine environmental monitoring and marine sensing technology, specifically to a device and method for measuring the facies fraction profile of deep-sea suspended sediments. Background Technology

[0002] Suspended sediments in seawater are widely present in environments such as estuaries, nearshore areas, harbors, submarine disturbance zones, and mining plume influence zones. The migration, diffusion, and sedimentation processes of suspended sediments not only affect water transparency and material transport, but are also closely related to sediment resuspension, topographic evolution, and changes in the marine ecological environment. Therefore, accurately obtaining the content and spatial distribution of suspended sediments in water bodies is an important issue in marine environmental monitoring and related engineering research.

[0003] Suspended sediment phase fraction refers to the volume proportion of suspended sediments in a unit volume of a mixed system of seawater and sediments. This parameter can directly characterize the proportion of suspended sediments in a water body and reflect its changes with depth and time.

[0004] Currently, the monitoring of suspended sediment content in seawater mainly employs optical methods, acoustic methods, and sampling analysis methods. Optical methods have a fast response and are widely used, but when the suspended sediment content is high, they are prone to signal saturation nonlinear distortion, affecting measurement accuracy. In addition, optical methods usually rely on optical windows, which are easily contaminated by attached substances and sediments during long-term deployment, leading to signal drift and increasing maintenance difficulty. Acoustic methods are suitable for water body detection within a certain range, but their measurement results are easily affected by differences in sediment particle size, morphology, and composition. Under conditions of high or complex suspended sediment content, acoustic signal interpretation is difficult, and measurement stability is also limited. Although on-site sampling methods can obtain more direct results, they usually rely on manual sampling and subsequent experimental processing, making it difficult to achieve continuous, real-time, and in-situ monitoring, and also unfavorable for obtaining distribution information at different depths at the same time.

[0005] In addition, existing measurement equipment is mostly based on single-point measurement. If it is necessary to obtain the distribution of suspended sediments along the depth direction, it is usually necessary to measure point by point by lifting the measurement equipment or moving the platform. This method is not only inefficient, but there is often a time difference between different nodes, which makes it difficult to truly reflect the vertical distribution characteristics of suspended sediments at the same time.

[0006] Therefore, there is an urgent need to provide a measurement device and method that is suitable for marine environments, can accurately reflect the vertical distribution characteristics of suspended sediments at the same time, and can adapt to conditions with high particle content, so as to meet the actual needs of marine environmental monitoring and related engineering applications. Summary of the Invention

[0007] The main objective of this invention is to provide a device and method for measuring the phasor fraction profile of deep-sea suspended sediments.

[0008] To achieve the above objectives, the present invention proposes a deep-sea suspended sediment facies profile measurement device, comprising: an installation assembly for installation in the water body along the water depth direction; multiple impedance measurement nodes spaced apart along the installation assembly, each impedance measurement node being equipped with an electrode probe for contacting the mixture of seawater and suspended sediment; and a main control and power supply unit electrically connected to each impedance measurement node, providing multi-frequency AC excitation signals to each impedance measurement node, acquiring multi-frequency impedance data response signals returned by each node, and calculating the suspended sediment facies at the location of each node based on the multi-frequency impedance data response signals.

[0009] Optionally, the main control and power supply unit is further configured to: generate multi-frequency AC excitation signals within a preset frequency range, and acquire the impedance amplitude, phase, and real and imaginary parts of the impedance at each frequency point to form multi-frequency impedance data.

[0010] Optionally, the impedance measurement node further includes: a housing for forming a waterproof sealed space to accommodate the circuit board, with the electrode probe connected to the circuit board; a temperature sensor connected to the circuit board for acquiring temperature information at the corresponding node; and a depth measurement unit connected to the circuit board for determining the depth of the corresponding node.

[0011] Optionally, the mounting assembly includes: a buoyancy element, a load-bearing element, and a counterweight element connected in sequence, with the impedance measurement nodes spaced apart on the load-bearing element.

[0012] Optionally, each impedance measurement node also integrates an electrode probe cleaning module, which is used to apply short-duration high-current-density pulses to the electrode probe at predetermined time intervals or according to the response state of the electrode probe for electrochemical cleaning.

[0013] Based on the same technical concept, this invention also proposes a method for measuring the facies fraction profile of deep-sea suspended sediments, using the deep-sea suspended sediment facies fraction profile measuring equipment described in any of the above claims. The method includes the following steps:

[0014] S1: Deploy the measuring equipment in the target sea area, so that multiple impedance measuring nodes are located at different depths; S2: Collect multi-frequency impedance data response signals of the seawater and suspended sediment mixture system at the depth of each node through the main control and power supply unit, and simultaneously collect temperature information at each node; S3: Calculate the suspended sediment phase fraction at each node based on the multi-frequency impedance data response signal and temperature information; S4: Determine the spatial height of each node based on the depth of each impedance measurement node, and construct an in-situ vertical profile of the phase fraction of suspended sediments by combining the calculated phase fraction of each node.

[0015] Optionally, calculating the suspended sediment phase fraction in step S3 includes the following sub-steps: S31: Use the temperature information synchronously collected by each node to perform temperature compensation on the multi-frequency impedance data of the corresponding node; S32: Extract at least one feature parameter from the compensated multi-frequency impedance data to serve as an auxiliary input for the particle phase fraction inversion model for operating condition identification, thereby selecting the model based on the operating condition results. The feature parameters include: real part of impedance, imaginary part of impedance, impedance amplitude, phase, characteristic frequency, low-frequency resistance, high-frequency resistance, and phase angle characteristic value. S33: Based on the electrode structure parameters, the compensated multi-frequency impedance data is converted into the equivalent complex conductivity or equivalent complex permittivity of the hybrid system, and the phase fraction is calculated using the particle phase fraction inversion model.

[0016] Optionally, in S33, converting the compensated multi-frequency impedance data into the equivalent complex conductivity or equivalent complex permittivity of the hybrid system specifically includes: first, converting the compensated multi-frequency impedance data... Find the complex admittance at the corresponding frequency Then, based on the parameters of the electrode probe or the conversion factor obtained through standard solution calibration, the complex admittance is converted into the equivalent complex conductivity of the mixed system. and according to The relationship between the dielectric constant and the complex permittivity yields the equivalent complex permittivity of the hybrid system. .

[0017] Optionally, the temperature compensation in S31 adopts the following formula: ; in, For a certain node at frequency The raw multi-frequency impedance data obtained below; For reference temperature; To convert to reference temperature Compensated multi-frequency impedance data; The temperature compensation coefficient at the corresponding frequency needs to be obtained through pre-calibration; The measured temperature is synchronously acquired by the temperature sensor.

[0018] Optionally, the calculation of suspended sediment phase fraction in S3 further includes: performing a corrected inversion by combining equivalent circuit analysis or experimental calibration parameters.

[0019] Optionally, the equivalent circuit analysis specifically includes: equating the seawater and suspended sediment mixture system to a parallel RC circuit, a series-parallel combined circuit, or an equivalent circuit model containing constant phase angle elements, and obtaining the equivalent resistance, equivalent capacitance, or constant phase angle element parameters from the compensated multi-frequency impedance data, and then using them as intermediate variables for particle phase fraction inversion. The experimental calibration parameters were corrected and inverted specifically by: preparing standard suspensions with different known particle phase fractions in the laboratory, calibrating the measurement results under different particle types, particle size ranges, and salinity conditions, and establishing an empirical fitting relationship between characteristic parameters and particle phase fractions using the following empirical model: ; in, For a set of multi-frequency characteristic parameters, For temperature, For salinity parameters, This is the set of model parameters obtained through experimental calibration. This can be a fitting function, a lookup table function, or a piecewise inversion function.

[0020] Optionally, in step S32, the following feature parameters are extracted: feature frequency. Low-frequency equivalent resistance High-frequency equivalent resistance and phase angle eigenvalues The feature parameters are combined to form a feature vector. To perform working condition identification, feature vector Represented as: .

[0021] Optionally, S4 specifically includes: constructing a vertical profile dataset for the measurement period; the main control and power supply units sort, correspond, and reconstruct the suspended sediment phase fractions at each node based on the spatial height information of each impedance measurement node, forming a vertical distribution result from near bottom to upper layers; the formula for constructing the vertical profile dataset for the measurement period is: , ; in, For the first The node height corresponding to each impedance measurement node; In the first Within each measurement cycle, the suspended sediment phase fraction at that node is calculated using S3; For the first Vertical profile data set within a measurement cycle; This represents the number of impedance measurement nodes.

[0022] Compared with existing technologies, the present invention has the following advantages: In the technical solution of the present invention, by setting multiple impedance measurement nodes at vertical intervals along the installation component, and with the centralized control and synchronous acquisition of the main control and power supply unit, it is possible to acquire multi-frequency impedance data response signals at different depths at one time. This can effectively overcome the problems of asynchronous measurement time and difficulty in obtaining a true vertical profile in traditional single-point measurement, and can truly reflect the vertical distribution characteristics of suspended sediments at the same time. Furthermore, this invention measures using multi-frequency impedance data response signals, which, compared to optical methods, does not rely on optical windows and can be placed on the bottom of the water for extended periods; compared to acoustic methods, it can suspend sediments with high content, resulting in more stable detection results. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of an embodiment of the deep-sea suspended sediment phase fraction profile measurement device of the present invention; Figure 2 This is a front view of the impedance measurement node; Figure 3 This is a schematic diagram of the impedance measurement node. Figure 4 A schematic diagram of the structure for installing and fixing the clips; Figure 5 A schematic diagram showing the variation trend of multi-frequency electrical impedance data under different particle phase fractions; Figure 6 A comparison of impedance-particle phase fraction curves before and after temperature compensation. Figure 7 The linearity comparison curves of the optical sensor and the method of the present invention are shown in the range of high particle phase fraction. Figure 8 A schematic diagram of the electrode electrochemical cleaning mechanism and a comparison of impedance spectra before and after cleaning; Figure 9 This is a schematic diagram of the vertical cross-section of the phase fraction.

[0025] Explanation of icon numbers: 1. Buoyancy element; 2. Power supply cable; 3. Impedance measurement node; 301. Hull; 302. Lower end cover; 303. Electrode probe; 304. Upper end cover; 305. Temperature sensor; 306. Depth measurement unit; 307. Sensor probe protective cover; 308. Circuit board; 309. Watertight component; 310. Mounting and fixing buckle; 4. Load-bearing element; 5. Main control and power supply unit; 6. Counterweight element.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0029] This invention proposes a device for measuring the phasor fraction profile of deep-sea suspended sediments.

[0030] Please refer to Figure 1-9 The deep-sea suspended sediment facies profile measurement device includes: an installation assembly for setting up in the water body along the water depth direction; multiple impedance measurement nodes 3 spaced apart along the installation assembly, each impedance measurement node 3 being equipped with an electrode probe 303 for contacting the mixture of seawater and suspended sediment; and a main control and power supply unit 5 electrically connected to each impedance measurement node 3, providing multi-frequency AC excitation signals to each impedance measurement node 3, acquiring multi-frequency impedance data response signals returned by each node, and calculating the suspended sediment facies at the location of each node based on the multi-frequency impedance data response signals.

[0031] The electrode probe 303 is made of platinum and has a surface coating to enhance its corrosion resistance and resistance to biofouling. The electrode probe 303 is used to directly contact the mixed system of seawater and suspended sediments and to acquire the multi-frequency impedance data response signal at the corresponding impedance measurement node 3 under multi-frequency AC excitation.

[0032] The main control and power supply unit 5 is used to provide working power and multi-frequency AC excitation signals to each impedance measurement node 3, and to complete node channel switching control, raw data acquisition, data storage and timed wake-up management.

[0033] Furthermore, the AC excitation frequency range is set to 100kHz to 10MHz, and 12 to 20 discrete frequency points are selected for a single measurement; the sampling time for each frequency point is 20ms to 100ms, the time for each node to complete a multi-frequency measurement is 1s to 3s, and the total time for all nodes to complete a profile measurement is preferably controlled within the range of 10s to 30s to ensure good synchronization of data at different depths.

[0034] In the technical solution of the present invention, by using multiple impedance measurement nodes 3 arranged vertically at intervals along the installation component, and in conjunction with the centralized control and synchronous acquisition of the main control and power supply unit 5, it is possible to acquire multi-frequency impedance data response signals at different depths at one time. This can effectively overcome the problems of asynchronous measurement time and difficulty in obtaining a true vertical profile in traditional single-point measurement, and can truly reflect the vertical distribution characteristics of suspended sediments at the same time. Furthermore, this invention measures using multi-frequency impedance data response signals, which, compared to optical methods, does not rely on optical windows and can be placed on the bottom of the water for extended periods; compared to acoustic methods, it can suspend sediments with high content, resulting in more stable detection results.

[0035] Optionally, the main control and power supply unit 5 is further configured to: generate multi-frequency AC excitation signals within a preset frequency range, and obtain the impedance amplitude, phase, and real and imaginary parts of the impedance at each frequency point to form multi-frequency impedance data.

[0036] Optionally, the impedance measurement node 3 further includes: a housing 301 for forming a waterproof sealed space to accommodate a circuit board 308, with an electrode probe 303 connected to the circuit board; a temperature sensor 305 connected to the circuit board 308 for acquiring temperature information at the corresponding node; and a depth measurement unit 306 connected to the circuit board 308 for determining the depth of the corresponding node. Integrating the temperature sensor 305 and the depth measurement unit 306 into the impedance measurement node 3 allows for the simultaneous acquisition of temperature and depth information at each node, enabling temperature compensation and spatial positioning of the impedance data, thereby improving the accuracy of the measurement results and the resolution of the vertical profile. Specifically, the temperature sensor 305 is integrated on or near the electrode probe 303 to synchronously acquire water temperature information at the corresponding node in order to perform temperature compensation on the impedance measurement results.

[0037] In this embodiment, each impedance measurement node 3 includes a cabin 301, a lower end cover 302, an electrode probe 303, an upper end cover 304, a temperature sensor 305, a depth measurement unit 306, a sensor probe protective cover 307, a circuit board 308, a watertight component 309, and a mounting and fixing buckle 310.

[0038] Optionally, the installation assembly includes: a buoyancy element 1, a load-bearing element 4, and a counterweight element 6 connected in sequence, with the impedance measurement nodes 3 spaced apart on the load-bearing element 4. This installation assembly has a simple structure and low water resistance, enabling the impedance measurement nodes 3 to be stably deployed vertically at different water depths, facilitating deep-sea deployment and recovery.

[0039] In this embodiment, the total length of the load-bearing element 4 is 25m, and the effective measurement section covers a range from 0.2m to 24m from the seabed. Eight impedance measurement nodes 3 are arranged vertically at non-uniform intervals, with heights from the seabed of 0.2m, 0.8m, 1.5m, 2.5m, 4m, 10m, 15m, and 24m, respectively. Among them, a denser arrangement is used in the range of 0.2m to 4m from the bottom to improve the resolution of the high particle fraction core layer and the gradient change near the bottom. A sparser arrangement is used in the water layer above 4m to characterize the upper transition layer and diffusion boundary position of the plume. Each impedance measurement node 3 is fixed to the load-bearing element 4 by a mounting and fixing buckle structure 310 and connected to the main control and power supply unit 5 through a power supply cable 2.

[0040] In this embodiment, the measuring equipment is deployed within a range of 5m to 30m downstream of the mining disturbance source. The counterweight element 6 sits on the bottom, and the buoyancy element 1 provides upward buoyancy, keeping the load-bearing element 4 basically vertical in the near-bottom water layer. During measurement, the main control and power supply unit 5 starts the operation of each impedance measurement node 3 according to a preset cycle. The electrode probe 303 in each node applies multi-frequency AC excitation to the seawater and suspended sediment mixture at its depth and collects the impedance response signal. The temperature sensor 305 simultaneously records the water temperature information at that node.

[0041] Furthermore, the standard measurement cycle can be set to 1 min to 5 min; when a sudden change in the impedance response of a low-level node is detected, the system can switch to encrypted observation mode, shortening the measurement cycle to 5 s to 20 s, in order to improve the ability to capture the rapid evolution of the plume.

[0042] Optionally, each impedance measurement node 3 also integrates an electrode probe cleaning module. This module applies short-duration high-current-density pulses to the electrode probe 303 at predetermined time intervals or according to the response state of the electrode probe 303 for electrochemical cleaning. The electrode probe cleaning module generates localized strong electric field disturbances at the interface between the electrode probe 303 and seawater through short-duration high-current-density pulses, as well as instantaneous charge-discharge impacts on the double layer. This removes adsorbed organic matter, colloidal particles, and initial adhesion of microorganisms from the electrode probe 303, thereby reducing the impact of bioattachment, particle deposition, and surface contamination on the measurement signal and improving stability and repeatability under long-term in-situ observation conditions.

[0043] In this embodiment, a short cleaning pulse is executed after every 50 to 200 profile measurements.

[0044] Please refer to Figure 8 Before cleaning, the adhesion or deposition on the surface of electrode probe 303 would cause the impedance response to deviate from the normal state; after cleaning, the impedance spectrum recovered and approached the reference clean state, indicating that electrochemical cleaning helps maintain measurement stability and long-term working reliability.

[0045] The present invention also proposes a method for measuring the facies fraction profile of deep-sea suspended sediments, using the deep-sea suspended sediment facies fraction profile measuring equipment described in any of the above claims, the method comprising the following steps: S1: Deploy the measuring equipment in the target sea area, so that multiple impedance measuring nodes 3 are positioned at different depths; S2: The main control and power supply unit 5 collects the multi-frequency impedance data response signal of the seawater and suspended sediment mixture system at the depth of each node, and simultaneously collects the temperature information at each node; S3: Calculate the suspended sediment phase fraction at each node based on the multi-frequency impedance data response signal and temperature information; S4: Based on the depth of each impedance measurement node 3, the spatial height of each node is determined. Combined with the calculated phase fraction of each node, an in-situ vertical profile of the suspended sediment phase fraction is constructed. By simultaneously acquiring multi-node multi-frequency impedance responses and constructing vertical profiles, efficient, in-situ, and synchronous profile measurement of suspended sediment phase fractions is achieved.

[0046] Optionally, calculating the suspended sediment phase fraction in step S3 includes the following sub-steps: S31: Using the temperature information synchronously collected by each node, temperature compensation is performed on the multi-frequency impedance data of the corresponding node to eliminate the influence of temperature. S32: Extract at least one of the following characteristic parameters from the compensated multi-frequency impedance data: real part of impedance, imaginary part of impedance, impedance magnitude, phase, and characteristic frequency. Low-frequency resistors High-frequency resistors Phase angle eigenvalues The working conditions are identified by using the auxiliary input of the particulate phase fraction inversion model, and the model is selected based on the working condition results. S33: Based on the structural parameters of electrode probe 303, the compensated multi-frequency impedance data is converted into the equivalent complex conductivity or equivalent complex permittivity of the hybrid system, and the phase fraction is calculated using the particle phase fraction inversion model (Maxwell-Garnett model or Bruggeman model) selected in S32. Through temperature compensation, feature parameter extraction, and equivalent complex conductivity or complex permittivity conversion, combined with the particle phase fraction inversion model, environmental interference can be effectively separated, significantly improving the accuracy of phase fraction calculation and operating condition identification capability.

[0047] Optionally, in S33, converting the compensated multi-frequency impedance data into the equivalent complex conductivity or equivalent complex permittivity of the hybrid system specifically includes: first, converting the compensated multi-frequency impedance data... Find the complex admittance at the corresponding frequency Then, based on the parameters of electrode probe 303 or the conversion factor obtained through standard solution calibration, the complex admittance is converted into the equivalent complex conductivity of the mixed system. and according to The relationship between the dielectric constant and the complex permittivity yields the equivalent complex permittivity of the hybrid system. .

[0048] Optionally, the temperature compensation in S31 adopts the following formula: ; in, For a certain node at frequency The raw multi-frequency impedance data obtained below; For reference temperature; To convert to reference temperature Compensated multi-frequency impedance data; The temperature compensation coefficient at the corresponding frequency needs to be obtained through pre-calibration; The measured temperature is synchronously acquired by temperature sensor 305.

[0049] Please refer to Figure 6 Before compensation, the impedance values ​​corresponding to the same particle phase fraction at different temperatures deviated; after compensation, the curves tended to coincide, indicating that temperature compensation can reduce the influence of temperature changes on the measurement results.

[0050] Optionally, the calculation of suspended sediment phase fraction in S3 further includes: performing a corrected inversion by combining equivalent circuit analysis or experimental calibration parameters, specifically including: establishing a set of characteristic parameters. ,temperature ,salinity With phase fraction Empirical fitting model between: ;in, This is the set of model parameters obtained from experimental calibration. The phase fraction of suspended sediments is corrected based on the empirically fitted model.

[0051] Optionally, in step S32, using the auxiliary input quantity as the particle phase fraction inversion model for working condition identification, and then selecting the model based on the working condition results, specifically includes: selecting a suitable mixed medium model from the effective medium theory based on the level of suspended sediment phase fraction, establishing a quantitative relationship between the equivalent complex permittivity and the suspended sediment phase fraction, and thus calculating the phase fraction.

[0052] Optionally, S4 specifically includes: the main control and power supply unit 5 sorts, corresponds, and reconstructs the suspended sediment phase fractions at each node according to the spatial height information of each impedance measurement node 3, forming a vertical distribution result from near bottom to upper layer, so as to construct a vertical profile dataset within the measurement period; the formula for constructing the vertical profile dataset within the measurement period (the vertical profile dataset is the suspended sediment phase fractions measured at each node organized according to different node heights to form a vertical profile at the same time) is: , ; in, For the first The node height corresponding to impedance measurement node 3; In the first Within each measurement cycle, the suspended sediment phase fraction at that node is calculated using S3; For the first Vertical profile data set within a measurement cycle; This represents the number of impedance measurement nodes (3).

[0053] Specifically, the spatial height corresponding to each impedance measurement node 3 is correlated with the suspended sediment phase fraction calculated by S3 to construct a vertical profile dataset of suspended sediment phase fraction at different heights within the same measurement cycle; the main control and power supply unit 5 sorts the node data in the vertical profile dataset according to the spatial height information of each impedance measurement node 3 to form a vertical distribution result of suspended sediment phase fraction from bottom to top.

[0054] Multi-frequency impedance data response signals of the seawater-suspended sediment mixture under different particle phase fraction conditions are collected by S2, and multi-frequency characteristic parameters such as the real part and imaginary part of impedance are extracted by S32 in S3. As the particle phase fraction increases, the real part and imaginary part of impedance curves undergo identifiable changes. This invention can distinguish the state of suspended sediment under different phase fraction conditions based on multi-frequency impedance characteristics. Please refer to Figure 5 As the particle phase fraction increases, both the real and imaginary impedance curves change, indicating that the multi-frequency impedance signal can distinguish the state of suspended sediments under different phase fraction conditions.

[0055] Please refer to Figure 7 Optical methods gradually deviate from the ideal straight line in the high particle phase fraction region, exhibiting a saturation trend; the method of the present invention still maintains a good linear relationship, indicating that it is more suitable for measuring suspended particles with high particle phase fraction.

[0056] In this embodiment, the specific steps of the deep-sea suspended sediment facies profile measurement method are as follows: Step 1: System deployment and impedance measurement node location.

[0057] The measurement system is deployed in the target sea area. The buoyancy element 1, the load-bearing element 4 and the counterweight element 6 make the system form a basically vertical or nearly vertical deployment state in the water. Multiple impedance measurement nodes 3 are fixed to different positions of the load-bearing element 4 by the installation and fixing buckle 310 structure, thereby forming in-situ nodes at different depths.

[0058] Step 2: Underwater multi-frequency impedance response and temperature information acquisition.

[0059] The main control and power supply unit 5 provides working power and multi-frequency AC excitation signals to each impedance measurement node 3. The electrode probe 303 in each impedance measurement node 3 performs multi-frequency impedance measurement on the seawater and suspended sediment mixture at its depth, and the temperature sensor 305 synchronously acquires the temperature information at the corresponding node, thereby obtaining multi-frequency impedance data and temperature data at different depth locations.

[0060] Step 3: Data transmission and particle phase fraction calculation.

[0061] Each impedance measurement node 3 transmits the collected multi-frequency impedance data and temperature data to the main control and power supply unit 5. The main control and power supply unit 5 performs preprocessing, temperature compensation, and characteristic parameter extraction on the data, and calculates the suspended sediment phase fraction at each node using the particle phase fraction inversion model. The preprocessing includes data denoising, outlier removal, frequency point, time, and node location correspondence.

[0062] Step 4: Profile construction and result output.

[0063] Based on the installation position of each impedance measurement node along the load-bearing element 4, determine the spatial height information corresponding to each node, and let the first node be... The node height corresponding to impedance measurement node 3 is: In the Within each measurement cycle, the suspended sediment phase fraction at that node was calculated using step three. This will generate a vertical profile dataset for the measurement period. : , ; Based on the spatial height information of each impedance measurement node 3, the main control and power supply unit 5 sorts, corresponds, and reconstructs the suspended sediment phase fractions at each node to form a vertical distribution result from near bottom to upper layer.

[0064] Furthermore, depending on the actual measurement requirements, linear interpolation, piecewise fitting, spline interpolation, or smoothing can be applied to the particle phase fraction data between adjacent nodes to obtain a continuous vertical distribution curve of suspended sediment phase fraction, thereby constructing an in-situ vertical profile of suspended sediment phase fraction.

[0065] In this embodiment, the main control and power supply unit 5 can further extract profile feature parameters such as plume thickness, peak phase fraction, corresponding height of the peak, vertical gradient, interface transition location, and influence range of high phase fraction based on the constructed vertical profile, and combine them with measurement time information to form continuous time-series profile results. The in-situ vertical profile results and their feature parameters can be stored and output by the main control and power supply unit 5 for subsequent determination of suspended sediment diffusion and stratification structure.

[0066] The specific construction of the particle phase fraction inversion model is as follows: To achieve a quantitative conversion from multi-frequency impedance response to suspended sediment phase fraction, this invention constructs a particle phase fraction inversion model based on temperature compensation, multi-frequency feature extraction, mixed medium theory, and experimental calibration correction (i.e., particle phase fraction inversion model = temperature compensation + multi-frequency feature parameter extraction + mixed medium model calculation + experimental calibration correction). This model is based on multi-frequency impedance data obtained from each impedance measurement node 5. First, the influence of ambient temperature is corrected. Then, characteristic parameters characterizing the electrical state of the seawater-suspended sediment mixture are extracted. Finally, combined with the equivalent medium model and experimental calibration parameters, the suspended sediment phase fraction at each node is calculated.

[0067] Temperature compensation: Because changes in seawater temperature affect the conductivity of the seawater phase and the overall electrical impedance response of the seawater-suspended sediment mixture, temperature compensation is required for the original multi-frequency electrical impedance data before performing fractional phase inversion. Let a node at a certain frequency... The raw multi-frequency impedance data obtained below are The reference temperature is The compensated multi-frequency impedance data can then be expressed as: ; in, To convert to reference temperature The compensated multi-frequency impedance data are as follows. The temperature compensation coefficient at the corresponding frequency needs to be obtained through pre-calibration. The measured temperature is synchronously acquired by temperature sensor 305.

[0068] Multi-frequency feature parameter extraction: After temperature compensation is completed, feature parameters are extracted from the compensated multi-frequency impedance data to obtain input quantities that can be used for particle phase fraction inversion; the feature parameters include, but are not limited to, one or more of the following: real part of impedance, imaginary part of impedance, impedance amplitude, phase, characteristic frequency, low-frequency resistance, high-frequency resistance, and phase angle feature value.

[0069] The characteristic parameters serve as auxiliary inputs for hybrid media model inversion, used for condition identification, model selection, model correction, or empirical calibration inversion.

[0070] In the basic inversion, the compensated multi-frequency impedance data can also be converted into equivalent complex conductivity or equivalent complex permittivity based on the electrode structure parameters, serving as the main input for the hybrid dielectric model inversion.

[0071] Specifically, the following feature parameters can be extracted: (1) Characteristic frequency That is, the frequency corresponding to the peak value of the imaginary part of the impedance or the phase characteristic point; (2) Low-frequency equivalent resistance That is, the equivalent resistance characteristic quantity reflecting the polarization effect of the particle interface in the low frequency range; (3) High-frequency equivalent resistance That is, the equivalent resistance characteristic quantity that reflects the overall volume conductivity of the two-phase mixed system in the high-frequency range; (4) Phase angle eigenvalues These are the extreme points or characteristic inflection points in the phase curve.

[0072] The characteristic parameters can be used for auxiliary inversion of particle phase fraction, working condition identification, model switching or correction calculation, and can be combined to form a feature vector. , represented as: .

[0073] Through feature quantity It can identify the operating conditions to determine whether the current suspension system is closer to a state with a low particle phase fraction and weak interparticle interaction, or a state with a high particle phase fraction and strong interparticle interaction. Based on the results of the working condition identification, when the particle phase fraction is low and the interparticle interaction is weak, the Maxwell-Garnett model is used; when the particle phase fraction is high and the interparticle interaction is strong, the Bruggeman model or a modified model is used. This step is a common technique in the field.

[0074] Based on the structural parameters of electrode probe 303, the compensated multi-frequency impedance data can be obtained. Equivalent complex conductivity converted to a hybrid system or equivalent complex permittivity Furthermore, based on the equivalent complex electrical parameters (equivalent complex conductivity) of the hybrid system... or equivalent complex permittivity ), to establish a quantitative relationship between the particle phase fraction and the equivalent electrical parameters of the mixed system.

[0075] Specifically, multi-frequency impedance data Equivalent complex conductivity converted to a hybrid system or equivalent complex permittivity The conversion method is as follows: The compensated multi-frequency impedance data can be used first. Find the complex admittance at the corresponding frequency Then, based on the structural parameters of electrode probe 303 (the spacing between electrode probes 303, the area of ​​electrode probe 303, and the electrode constant of electrode probe 303) or the conversion factor obtained by calibration with standard solution, the complex admittance is converted into the equivalent complex conductivity of the mixed system. Further based on The relationship between the dielectric constant and the complex permittivity yields the equivalent complex permittivity of the hybrid system. The seawater-suspended sediment system can be regarded as a two-phase mixed system consisting of a continuous seawater phase and a dispersed particle phase. When the particle phase fraction changes, the equivalent dielectric constant and equivalent electrical conductivity of the mixed system change accordingly. Therefore, a quantitative relationship between the particle phase fraction and the equivalent electrical parameters can be established based on the mixed medium theory.

[0076] For cases with low particle phase fraction and weak interactions between particle phases, the Maxwell-Garnett mixed media model is adopted: ; The particle phase fraction can be obtained from this. : ; For cases with a high particle phase fraction and strong interactions between particle phases, the Bruggeman effective medium model is adopted: ; By solving the above equations, the phase fraction of suspended sediments under high particle phase fraction conditions can be obtained. ; In the calculation formula of the above model, The fraction of suspended sediment phases; The equivalent complex permittivity of seawater can be obtained by calibrating seawater. The equivalent complex permittivity of the granular phase can be obtained by calibrating seabed sediment samples; The equivalent complex permittivity of the hybrid system is calculated from the compensated multi-frequency impedance data.

[0077] In this embodiment, corresponding to the inversion under the basic operating conditions, there is also a modified inversion method for complex operating conditions: In real-world seawater environments, considering the complex conditions such as particle type, particle size distribution, salinity, and electrode interface effects, this method, based on the particle phase fraction inversion results derived from the mixed-medium theory, further modifies the results in step S33 by incorporating equivalent circuit analysis or experimental calibration parameters. This correction step is a preferred implementation method and not a necessary prerequisite for particle phase fraction inversion. That is, if different sediments, temperatures, salinities, etc., are encountered, experimental correction and calibration need to be performed again to improve the inversion accuracy.

[0078] Specifically, the seawater and suspended sediment mixture system is equivalent to a parallel RC circuit, a series-parallel combined circuit, or an equivalent circuit model containing constant phase angle elements. The equivalent resistance, equivalent capacitance, or constant phase angle element parameters are obtained by inverting the compensated multi-frequency impedance data, and then used as intermediate variables for particle phase fraction inversion.

[0079] Furthermore, by preparing standard suspensions with different known particle phase fractions in the laboratory, the measurement results under different particle types, particle size ranges, and salinity conditions were calibrated. The following empirical model was used to establish an empirical fitting relationship between characteristic parameters and particle phase fraction: ; in, For a set of multi-frequency characteristic parameters, For temperature, For salinity parameters, This is the set of model parameters obtained through experimental calibration. This can be a fitting function, a lookup table function, or a piecewise inversion function. Salinity The model parameter set can be calculated based on measured conductivity parameters, temperature, and pressure, according to the PSS-78 practical salinity scale. It is a set of parameters determined by fitting, table lookup or piecewise inversion after experimental calibration using a standard suspension with a known particle phase fraction under corresponding particle type, particle size range and salinity conditions. It is used to characterize the correspondence between multi-frequency characteristic parameters, temperature and salinity and particle phase fraction.

[0080] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made under the concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A device for measuring the facies fraction profile of deep-sea suspended sediments, characterized in that, include: Installation components for installation in water bodies along the water depth direction; Multiple impedance measurement nodes (3) are spaced along the mounting assembly, and each impedance measurement node (3) is provided with an electrode probe (303) for contacting the mixture of seawater and suspended sediment. The main control and power supply unit (5) is electrically connected to each impedance measurement node (3), provides multi-frequency AC excitation signals to each impedance measurement node (3), collects multi-frequency impedance data response signals returned by each node, and calculates the suspended sediment phase fraction at the location of each node based on the multi-frequency impedance data response signals.

2. The deep-sea suspended sediment facies profile measurement device according to claim 1, characterized in that, The main control and power supply unit (5) is also configured to generate multi-frequency AC excitation signals within a preset frequency range, and obtain the impedance amplitude, phase and real and imaginary parts of the impedance at each frequency point to form multi-frequency impedance data.

3. The deep-sea suspended sediment facies profile measurement device according to claim 1 or 2, characterized in that, The impedance measurement node (3) also includes: The chamber (301) is used to form a waterproof and sealed space to accommodate the circuit board (308), and the electrode probe (303) is connected to the circuit board (308); A temperature sensor (305) is connected to a circuit board (308) to acquire temperature information at the corresponding node; A depth measurement unit (306) is connected to a circuit board (308) and is used to determine the depth of the corresponding node.

4. The deep-sea suspended sediment facies fraction profile measuring device according to claim 1, characterized in that, The installation assembly includes a buoyancy element (1), a load-bearing element (4), and a counterweight element (6) connected in sequence, with the impedance measurement node (3) installed at intervals on the load-bearing element (4).

5. The deep-sea suspended sediment facies fraction profile measuring device according to claim 1, characterized in that, Each impedance measurement node (3) also integrates an electrode probe cleaning module, which is used to apply short-duration high current density pulses to the electrode probe (303) at predetermined time intervals or according to the response state of the electrode probe (303) for electrochemical cleaning.

6. A method for measuring the facies fraction profile of deep-sea suspended sediments, characterized in that, The measurement is performed using the deep-sea suspended sediment facies fraction profile measuring device according to any one of claims 1-5, and the method includes the following steps: S1: Deploy the measuring equipment in the target sea area, so that multiple impedance measuring nodes (3) are located at different depths; S2: The main control and power supply unit (5) collects the multi-frequency impedance data response signal of the seawater and suspended sediment mixture system at the depth of each impedance measurement node (3), and simultaneously collects the temperature information at each impedance measurement node (3); S3: Calculate the suspended sediment phase fraction at each impedance measurement node (3) based on the multi-frequency impedance data response signal, temperature information and structural parameters of the electrode probe (303); S4: Determine the spatial height of each impedance measurement node (3) based on the depth of each impedance measurement node (3), and construct an in-situ vertical profile of the suspended sediment phase fraction by combining the suspended sediment phase fraction obtained at each impedance measurement node (3) in S3.

7. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 6, characterized in that, The calculation of the suspended sediment phase fraction in step S3 includes the following sub-steps: S31: Use the temperature information synchronously collected by each node to perform temperature compensation on the multi-frequency impedance data of the corresponding node; S32: Extract at least one feature parameter from the temperature-compensated multi-frequency impedance data to serve as an auxiliary input for the particle phase fraction inversion model for operating condition identification, thereby selecting the model based on the operating condition results. The feature parameters include: real part of impedance, imaginary part of impedance, impedance amplitude, phase, characteristic frequency, low-frequency resistance, high-frequency resistance, and phase angle characteristic value. S33: Based on the structural parameters of the electrode probe (303), the compensated multi-frequency impedance data is converted into the equivalent complex conductivity or equivalent complex permittivity of the hybrid system, and the phase fraction is calculated using the particle phase fraction inversion model selected in S32.

8. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 7, characterized in that, In S33, converting the compensated multi-frequency impedance data into the equivalent complex conductivity or equivalent complex permittivity of the hybrid system specifically includes: first, from the compensated multi-frequency impedance data... Find the complex admittance at the corresponding frequency Then, based on the parameters of the electrode probe (303) or the conversion factor obtained by standard solution calibration, the complex admittance is converted into the equivalent complex conductivity of the mixed system. and according to The relationship between the dielectric constant and the complex permittivity yields the equivalent complex permittivity of the hybrid system. .

9. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 7, characterized in that, The temperature compensation in S31 uses the following formula: ； in, For a certain node at frequency The raw multi-frequency impedance data obtained below; For reference temperature; To convert to reference temperature Compensated multi-frequency impedance data; The temperature compensation coefficient at the corresponding frequency needs to be obtained through pre-calibration; The measured temperature is synchronously acquired by the temperature sensor (305).

10. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 8, characterized in that, The calculation of suspended sediment phase fraction in S3 also includes: correcting and inverting by combining equivalent circuit analysis or experimental calibration parameters.

11. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 10, characterized in that, The equivalent circuit analysis specifically includes: equating the seawater and suspended sediment mixture system to a parallel RC circuit, a series-parallel combined circuit, or an equivalent circuit model containing constant phase angle elements, and obtaining the equivalent resistance, equivalent capacitance, or constant phase angle element parameters from the compensated multi-frequency impedance data, and then using them as intermediate variables for particle phase fraction inversion. The experimental calibration parameters were corrected and inverted specifically by: preparing standard suspensions with different known particle phase fractions in the laboratory, calibrating the measurement results under different particle types, particle size ranges, and salinity conditions, and establishing an empirical fitting relationship between characteristic parameters and particle phase fractions using the following empirical model: ； in, For a set of multi-frequency characteristic parameters, For temperature, For salinity parameters, This is the set of model parameters obtained through experimental calibration. This can be a fitting function, a lookup table function, or a piecewise inversion function.

12. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 7, characterized in that, In step S32, the following feature parameters are extracted: feature frequency. Low-frequency equivalent resistance High-frequency equivalent resistance and phase angle eigenvalues The feature parameters are combined to form a feature vector. To perform working condition identification, feature vector Represented as: 。 13. The method for measuring the facies fraction profile of deep-sea suspended sediments according to claim 6, characterized in that, S4 specifically includes: the main control and power supply unit (5) sorts, corresponds, and reconstructs the suspended sediment phase fractions at each node according to the spatial height information of each impedance measurement node (3), forming a vertical distribution result from near bottom to upper layer, so as to construct a vertical profile dataset within the measurement period; the formula for constructing the vertical profile dataset within the measurement period is: ， ； in, For the first The node height corresponding to each impedance measurement node (3); In the first Within each measurement cycle, the suspended sediment phase fraction at that node is calculated using S3. For the first Vertical profile dataset within a measurement cycle; The number of impedance measurement nodes (3).

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