Method for measuring and calculating internal stratification intensity of deep sea turbidity current

Abstract

The invention discloses a method for measuring and calculating the internal stratification intensity of deep sea turbidity current, and belongs to the technical field of ocean observation. Aiming at the problems that multi-source data fusion is insufficient and stratification intensity calculation is not suitable for a high suspended sand strong shear turbidity current process in existing anchor system observation, the method comprises the following steps: synchronously acquiring flow velocity, temperature, salinity, pressure and turbidity data of multiple vertical points, and after time synchronization and horizon matching pretreatment, identifying a turbidity current time period by combining turbidity, flow velocity and temperature-salinity change; constructing an equivalent density profile in combination with suspended sediment concentration contribution, and calculating a stratification strength parameter; and finally, a gradient Richardson number is calculated in combination with vertical velocity shearing so as to quantitatively characterize a stratified structure and a mixed state in the turbidity current, and data support is provided for deep-sea engineering geological disaster risk assessment.

Description

Technical Field

[0001] This invention belongs to the field of marine observation technology, and in particular relates to a method for measuring and calculating the stratification intensity inside deep-sea turbidity currents. Background Technology

[0002] Deep-sea turbidity currents, as a high-energy, high-density gravity flow process, occur frequently in deep-sea canyons, submarine fans, and trenches. Their sudden onset, long duration, and large transport volume pose a serious threat to deep-sea engineering facilities such as subsea oil and gas pipelines and communication cables. The water structure and dynamic processes within turbidity currents directly determine the mode and intensity of their damage to engineering facilities. Therefore, refined observation and quantitative characterization of the water structure characteristics during turbidity current events have become a critical technical problem urgently needing to be solved in deep-sea geological hazard monitoring and engineering risk assessment. Currently, in-situ observation of deep-sea turbidity current processes mainly relies on moored observation systems. These systems typically integrate acoustic Doppler current profilers to acquire velocity and direction information, temperature chains to characterize the water temperature stratification, and turbidity chains or suspended sediment concentration sensors to reflect changes in particulate matter concentration. These systems can continuously record turbidity current events over long timescales and have been widely used in research and monitoring.

[0003] However, current observational practices largely focus on the independent analysis of single physical quantities such as velocity, temperature, or turbidity, or only provide qualitative comprehensive descriptions, without establishing a unified analytical framework that can effectively integrate multi-source heterogeneous data such as velocity, temperature, salinity, and turbidity. This limits our overall understanding of turbidity currents as a complex multi-physics coupled process. More importantly, stratification intensity, as a core indicator describing water stability, mixing state, and energy dissipation characteristics, is crucial for understanding the internal structure and development mechanism of turbidity currents. Existing methods for calculating stratification intensity are mostly based on water density profiles under idealized or near-static steady-state conditions and heavily rely on continuous, high-resolution vertical profile data. This calculation model is difficult to directly apply to the deep-sea turbidity current environment, which has high suspended sediment concentration, high-velocity shear, and strong unsteady-state characteristics. In actual moored observation scenarios, sensors are discretely deployed along the ropes, and the sampling times of different instruments are asynchronous, making it extremely difficult to obtain continuous, synchronous, high-resolution vertical profile data. Therefore, under current engineering observation conditions, there is a lack of a quantitative calculation method and system for turbidity stratification intensity that can effectively integrate multi-source asynchronous data and is suitable for long-term continuous operation in the field. This directly limits the in-depth understanding and accurate assessment of key scientific issues and engineering risks such as the internal mixing process of turbidity currents, the unstable development mechanism, and its impact on seabed erosion. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for measuring and calculating the stratification intensity within deep-sea turbidity currents. This method effectively integrates multi-source asynchronous observation data such as flow velocity, temperature, salinity, and turbidity under the condition of discrete deployment of moored observation systems, enabling quantitative calculation of water stratification intensity during deep-sea turbidity currents.

[0005] To achieve the above objectives, the present invention provides a method for measuring and calculating the stratification intensity within deep-sea turbidity currents, comprising:

[0006] Based on the vertically deployed anchored observation system, multi-source observation data of water velocity, temperature, salinity, pressure and turbidity at different depths are obtained;

[0007] The multi-source observation data is preprocessed for time synchronization and spatial stratification matching to form a time-space aligned joint dataset;

[0008] Based on the preprocessed turbidity and flow velocity data, the time periods of turbidity events are identified;

[0009] Based on temperature, salinity, pressure, and turbidity data during the period of the turbidity event, an equivalent density profile including the contribution of suspended sediment concentration was constructed.

[0010] Based on the equivalent density profile, the stratification intensity parameters characterizing the stability of the water body are calculated;

[0011] By combining the stratification intensity parameters with the vertical velocity shear of the corresponding time period and layer, the gradient Richardson number is calculated to analyze the mixing state inside the turbidity current.

[0012] Optionally, acquiring multi-source observation data includes:

[0013] The anchorage observation system is equipped with an acoustic Doppler current profiler, a temperature, salinity, and depth measuring instrument, a turbidity measuring instrument, and a sediment trap along its vertical direction.

[0014] Among them, the temperature, salinity, depth and turbidity measuring instrument and the turbidity measuring instrument are set up on the same floor to collect temperature, salinity, pressure and turbidity data simultaneously;

[0015] Acoustic Doppler current profilers are used to acquire flow velocity profile data;

[0016] Sediment traps are used to obtain suspended sediment samples to calibrate the relationship between turbidity and suspended sediment concentration.

[0017] Optionally, the preprocessing of the multi-source observation data for time synchronization and spatial stratigraphic matching includes:

[0018] Unify and correct the time base of data from different sensors, and resample all data to a uniform time resolution;

[0019] The flow velocity data obtained by the acoustic Doppler current profiler is vertically matched with the temperature, salinity, depth and turbidity measurement data at the corresponding height.

[0020] The matched data is smoothed to suppress high-frequency noise.

[0021] Optionally, identifying the time period of turbidity events includes:

[0022] A sudden increase in turbidity data exceeding a preset threshold is used as a preliminary criterion;

[0023] A secondary identification is performed by combining the significant increase in flow velocity and the vertical consistency of flow direction within the corresponding time period;

[0024] By utilizing anomalous changes in temperature and salinity data to eliminate non-turbidity flow interference processes, the start and end times of turbidity flow events were ultimately determined.

[0025] Optionally, constructing an equivalent density profile includes:

[0026] Background seawater density was calculated using temperature, salinity, and pressure data;

[0027] Turbidity data from sediment samples were calibrated, and suspended sediment concentration was obtained by inversion.

[0028] The equivalent density is calculated by superimposing the contribution of suspended sediment concentration to the density on the background seawater density.

[0029] Optionally, the calculation of layering intensity parameters includes:

[0030] The equivalent density profile is subjected to vertical difference to obtain the vertical gradient of the equivalent density.

[0031] Substituting the vertical gradient into the formula for calculating the Brønsted-Weiser frequency yields the layering intensity parameter.

[0032] Optionally, calculating the gradient Richardson number to analyze the internal mixing state of the turbidity stream includes:

[0033] Based on the velocity profile data during the period of the turbidity event, the vertical velocity shear is calculated;

[0034] Divide the stratification intensity parameter by the vertical velocity shear at the corresponding time and layer to obtain the gradient Richardson number;

[0035] Based on the numerical range of the Richardson number, the stability of the water body and the conditions for the development of turbulent mixing are determined.

[0036] Optional, vertically deployed anchored observation systems include:

[0037] A combination sensor of temperature, salinity and turbidity measuring instrument is fixedly installed at different heights along the vertical from bottom to top on the anchoring rope;

[0038] An acoustic Doppler current profiler is installed at a preset height from the bottom.

[0039] An acoustic release device and a counterweight are installed at the bottom of the anchor system, and a buoy to provide buoyancy is connected at the top.

[0040] An electronic device, the electronic device comprising: a processor and a memory storing computer program instructions;

[0041] When the processor executes the computer program instructions, it implements the method for measuring and calculating the stratification intensity inside the deep-sea turbidity current.

[0042] A computer storage medium storing computer program instructions, which, when executed by a processor, implement the method for measuring and calculating the stratification intensity inside deep-sea turbidity currents.

[0043] Technical Advantages of this Invention: This invention discloses a method for measuring and calculating the stratification intensity within deep-sea turbidity currents. It effectively integrates multi-source asynchronous observation data such as velocity, temperature, salinity, and turbidity under the condition of discrete moored observation systems, enabling quantitative calculation of water stratification intensity during deep-sea turbidity currents. By introducing the influence of suspended sediment concentration on density to construct an equivalent density parameter, it overcomes the limitations of traditional stratification intensity calculation methods that rely on static stability assumptions and high-resolution continuous profiles, making it applicable to unsteady turbidity current environments with high suspended sediment and strong shear. Furthermore, this invention combines the calculated vertical velocity shear to construct a gradient Richardson number, thereby effectively characterizing the relative relationship between stratification and shearing during turbidity current processes and identifying key periods and layers of shear instability and enhanced mixing. This method does not rely on high-frequency microstructure observation equipment and can be implemented based on conventional moored observation data, providing a highly feasible and easily promoted technical means for the study of deep-sea turbidity current dynamic processes and disaster risk monitoring of seabed engineering facilities. Attached Figure Description

[0044] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0045] Figure 1This is a schematic diagram of the structure of an anchored observation system for measuring the stratification intensity inside deep-sea turbidity currents according to an embodiment of the present invention. 1 is a glass buoy; 2-9 are temperature, salinity, and depth measuring instruments with turbidity sensors; 10 is a Kevlar cable; 11 is an ADCP and its mounting frame; 12-13 are sediment traps and their mounting frames; 14 is an acoustic release device and its parallel structure; and 15 is a weight.

[0046] Figure 2 This is a flowchart illustrating a method for measuring and calculating the stratification intensity inside deep-sea turbidity currents according to an embodiment of the present invention. Detailed Implementation

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0049] like Figures 1-2 As shown, this embodiment also provides a method for measuring and calculating the stratification intensity inside deep-sea turbidity currents, including:

[0050] Based on the vertically deployed anchored observation system, multi-source observation data of water velocity, temperature, salinity, pressure and turbidity at different depths are obtained;

[0051] The multi-source observation data is preprocessed for time synchronization and spatial stratification matching to form a time-space aligned joint dataset;

[0052] Based on the preprocessed turbidity and flow velocity data, the time periods of turbidity events are identified;

[0053] Based on temperature, salinity, pressure, and turbidity data during the period of the turbidity event, an equivalent density profile including the contribution of suspended sediment concentration was constructed.

[0054] Based on the equivalent density profile, the stratification intensity parameters characterizing the stability of the water body are calculated;

[0055] By combining the stratification intensity parameters with the vertical velocity shear of the corresponding time period and layer, the gradient Richardson number is calculated to analyze the mixing state inside the turbidity current.

[0056] Furthermore, acquiring multi-source observation data includes:

[0057] The anchorage observation system is equipped with an acoustic Doppler current profiler, a temperature, salinity, and depth measuring instrument, a turbidity measuring instrument, and a sediment trap along its vertical direction.

[0058] Among them, the temperature, salinity, depth and turbidity measuring instrument and the turbidity measuring instrument are set up on the same floor to collect temperature, salinity, pressure and turbidity data simultaneously;

[0059] Acoustic Doppler current profilers are used to acquire flow velocity profile data;

[0060] Sediment traps are used to obtain suspended sediment samples to calibrate the relationship between turbidity and suspended sediment concentration.

[0061] Furthermore, the vertically deployed anchored observation system includes:

[0062] A combination sensor of temperature, salinity and turbidity measuring instrument is fixedly installed at different heights along the vertical from bottom to top on the anchoring rope;

[0063] An acoustic Doppler current profiler is installed at a preset height from the bottom.

[0064] An acoustic release device and a counterweight are installed at the bottom of the anchor system, and a buoy to provide buoyancy is connected at the top.

[0065] Specifically, the implementation process of this embodiment includes:

[0066] Multi-source observation data acquisition: Multi-source in-situ observation data at different water depths are acquired using an anchored observation system. Key instruments include an acoustic Doppler current profiler (ADCP), a temperature, salinity, and depth meter (CTD), a turbidity meter (TU), and a sediment sampler, with the CTD and turbidity meter located in the same position. The observation data includes at least flow velocity, temperature, turbidity, salinity, and pressure data, and sediment samples are acquired during the passage of the turbidity current. Sensors are vertically distributed at different depths to measure the changes in hydrodynamic and physical parameters during the turbidity current. Figure 1As shown, the total length of the anchorage is at least over 100m. 1 is a glass buoy located at the top of the anchorage; 2-9 are CTDs with TUs, fixed to the anchorage ropes using clamps. 9 is 10m above the bottom, 8-4 are 20, 30, 40, 50, and 60m above the bottom respectively, and 3 and 2 are 70 and 80m above the bottom respectively. The sampling interval is set to 1 minute; 10 is a Kevlar cable, connecting the various parts via a figure-eight swivel and shackles; 11 is the ADCP and its protective frame, 65m above the bottom. m, sampling interval set to 1 minute; 12 and 13 are both sediment traps and their mounting frames, at heights of 45 and 15 m from the bottom respectively. Each sediment consists of a funnel-shaped device with an opening diameter of 30 cm and a PVC pipe of 1 m in length, with a built-in timer. A plastic sheet is dropped every 10 days. The trap can capture suspended sediments in seawater, especially during turbidity currents; 14 is an acoustic release device, at a height of 8 m from the bottom; 15 is a cement block, weighing approximately 1.5 tons.

[0067] Furthermore, the preprocessing of the multi-source observation data for time synchronization and spatial stratigraphic matching includes:

[0068] Unify and correct the time base of data from different sensors, and resample all data to a uniform time resolution;

[0069] The flow velocity data obtained by the acoustic Doppler current profiler is vertically matched with the temperature, salinity, depth and turbidity measurement data at the corresponding height.

[0070] The matched data is smoothed to suppress high-frequency noise.

[0071] Specifically, the implementation process of this embodiment includes:

[0072] Data Preprocessing: For multi-source data such as velocity, temperature, salinity, pressure, and turbidity obtained from long-term continuous observations of the anchorage, a unified data preprocessing is performed on the raw observation data before calculating stratification intensity and gradient Richardson number. This ensures the comparability of data from different sensors in time and space, as well as computational stability. Since the sampling start time and internal clocks of different sensors differ, the time of each sensor is first uniformly calibrated, converting ADCP velocity data, CTD data, and turbidity meter data to the same time reference. Subsequently, according to a preset time resolution (e.g., 1 minute), various types of data are resampled using time averaging or linear interpolation to ensure that multi-source observation data correspond to the same set of vertical observation layers at the same time. For the velocity profile data acquired by ADCP, the velocity data is matched with the CTD and turbidity meter data at the corresponding height based on its vertical resolution (e.g., 2 m). To reduce the impact of short-term high-frequency noise on vertical velocity shear calculations, the velocity data can be smoothed in time or vertically without altering the overall velocity structure characteristics during turbidity currents. After completing the above preprocessing steps, the flow velocity, temperature, salinity, pressure and turbidity data at the same time and vertical layer are checked for consistency to confirm that there is no obvious time mismatch or layer deviation and that the input requirements for stratification intensity and gradient Richardson number calculation are met.

[0073] Furthermore, identifying the time periods of turbidity events includes:

[0074] A sudden increase in turbidity data exceeding a preset threshold is used as a preliminary criterion;

[0075] A secondary identification is performed by combining the significant increase in flow velocity and the vertical consistency of flow direction within the corresponding time period;

[0076] By utilizing anomalous changes in temperature and salinity data to eliminate non-turbidity flow interference processes, the start and end times of turbidity flow events were ultimately determined.

[0077] Specifically, the implementation process of this embodiment includes:

[0078] Turbidity Period Identification: Firstly, turbidity meter observation data is used as a direct indicator of turbidity occurrence. By setting a turbidity threshold relative to the background value or the magnitude of a sudden increase in turbidity, potential candidate turbidity periods are initially screened. When turbidity shows a sustained increase or rapid enhancement across multiple adjacent observation layers, a significant suspended sediment transport process is identified during this period. Based on this, velocity profile data obtained from ADCP is used to further identify the magnitude of velocity and its vertical structure changes within the candidate periods. When a significant increase in velocity is observed during periods of increased turbidity, and there is a consistent flow direction or enhanced vertical velocity shear between different vertical layers, the process is considered to possess the dynamic characteristics of turbidity. Simultaneously, temperature and salinity data obtained from CTD are used to analyze whether there are abnormal changes in water temperature and salinity (such as increased temperature or decreased salinity) to rule out non-turbidity processes caused solely by background currents or internal waves. Finally, by combining the criteria of abnormally increased turbidity, abrupt changes in flow velocity structure, and changes in water characteristics, the start and end times and duration of turbidity flow were determined, thereby enabling automatic or semi-automatic identification of turbidity flow periods in long-term anchorage observation data. This provides a reliable basis for time period division for subsequent analysis of stratification intensity, gradient Richardson number, and mixing state.

[0079] Furthermore, constructing the equivalent density profile includes:

[0080] Background seawater density was calculated using temperature, salinity, and pressure data;

[0081] Turbidity data from sediment samples were calibrated, and suspended sediment concentration was obtained by inversion.

[0082] The equivalent density is calculated by superimposing the contribution of suspended sediment concentration to the density on the background seawater density.

[0083] Specifically, the implementation process of this embodiment includes:

[0084] Construction of equivalent density and its vertical gradient: Background seawater density is calculated using temperature, salinity, and pressure data. In the specific implementation, the GSW (Gibbs SeaWater) Oceanographic Toolbox in MATLAB is preferred. This toolbox has a built-in seawater state equation algorithm conforming to international standards, which can automatically calculate seawater density under corresponding conditions based on input temperature, salinity, and pressure data. Suspended sediment concentration is calibrated and inverted using sediment samples and turbidity data combined with indoor experiments, introducing the influence of suspended sediment concentration on water density, and constructing equivalent density parameters that consider the contribution of particulate matter, thereby reflecting the actual density distribution characteristics of water bodies under high suspended sediment conditions in turbidity currents. Based on the equivalent density data discretely deployed vertically by the anchor mooring, adjacent measuring point difference is used. That is, for multi-layer observation data that has completed time synchronization and quality control, two adjacent measuring points in the vertical direction are selected at the same observation time, and their corresponding physical quantity values ​​and vertical position heights are obtained respectively. By calculating the difference in physical quantities between adjacent measuring points and dividing it by the vertical distance between the two measuring points, the vertical gradient of that physical quantity within the interlayer range is obtained. Ultimately, the vertical distribution and gradient information of the equivalent density of the water body during turbidity flow were obtained.

[0085] Furthermore, the calculation of layering intensity parameters includes:

[0086] The equivalent density profile is subjected to vertical difference to obtain the vertical gradient of the equivalent density.

[0087] Substituting the vertical gradient into the formula for calculating the Brønsted-Weiser frequency yields the layering intensity parameter.

[0088] Specifically, the implementation process of this embodiment includes:

[0089] Stratification intensity and gradient Richardson number calculation: To quantitatively characterize the interaction between water stratification and velocity shear during turbidity currents, and to determine whether the turbidity current possesses the kinetic conditions for shear instability and enhanced mixing, the gradient Richardson number is introduced as a key criterion parameter. The gradient Richardson number is used to characterize the relative strength between water stability and velocity shear, and is defined as the ratio of stratification intensity to the square of the vertical velocity shear, specifically expressed as:

[0090] ;

[0091] Where U represents the flow velocity at different strata obtained by ADCP, and z is the vertical coordinate. When Ri < 0.25, shear instability is prevalent, and turbulence is easily generated; when Ri > 1, stratification dominates, and turbulence is suppressed. Based on the vertical gradient of the equivalent density, the stratification intensity parameter (equivalent Brunt–Väisälä frequency) is calculated using the stable frequency parameter (N) obtained based on the vertical distribution characteristics of the equivalent density. 2 eq This parameter reflects the water body's response to vertical disturbances under gravity, and is used to quantitatively describe the stability and stratification of the water body. A large value indicates that the water density changes significantly with depth, vertical mixing is suppressed, and the water body is in a strong stratification state; a small value indicates a weak density gradient, and the water body is more prone to vertical mixing; a negative value or close to zero indicates that the water body is in an unstable or nearly completely mixed state.

[0092] Furthermore, calculating the gradient Richardson number to analyze the internal mixing state of the turbidity stream includes:

[0093] Based on the velocity profile data during the period of the turbidity event, the vertical velocity shear is calculated;

[0094] Divide the stratification intensity parameter by the vertical velocity shear at the corresponding time and layer to obtain the gradient Richardson number;

[0095] Based on the numerical range of the Richardson number, the stability of the water body and the conditions for the development of turbulent mixing are determined.

[0096] Specifically, the implementation process of this embodiment includes:

[0097] The stable frequency parameter can intuitively reflect the evolution characteristics of water stratification structure during turbidity flow, and its calculation form is as follows:

[0098] ;

[0099] Where g is the acceleration due to gravity; ρ0 is the reference density used for normalization; ρ eq To account for the equivalent density caused by suspended sediment, a density parameter is obtained by introducing the effect of suspended sediment concentration on water density, based on the background seawater density determined by temperature, salinity, and pressure. Its expression is as follows:

[0100] ;

[0101] The background seawater density is calculated from temperature T, salinity S, and pressure p; C sα represents the suspended sediment concentration or particulate matter volume concentration; α is the conversion coefficient of the contribution of suspended sediment to water density, used to characterize the influence of particulate matter on density, and is set to 1 here.

[0102] In the specific implementation process, the velocity difference between adjacent observation layers is calculated by using the multi-layer velocity profile observation data arranged vertically on the anchor system, and the vertical velocity shear is obtained by combining the vertical distance of the corresponding layer. At the same time, the equivalent density profile is calculated by using the temperature, salinity and turbidity observation data arranged in the same layer, and the equivalent buoyancy frequency square is further obtained, thereby realizing the hourly or layer-by-layer calculation of the gradient Richardson number.

[0103] An electronic device, the electronic device comprising: a processor and a memory storing computer program instructions;

[0104] When the processor executes the computer program instructions, it implements the method for measuring and calculating the stratification intensity inside the deep-sea turbidity current.

[0105] A computer storage medium storing computer program instructions, which, when executed by a processor, implement the method for measuring and calculating the stratification intensity inside deep-sea turbidity currents.

[0106] An application example of this invention is shown below:

[0107] The method for measuring and calculating the intensity of deep-sea turbidity stratification was applied to long-term moored observations in the Kaoping Canyon or Manila Trench area in the northeastern South China Sea. Multiple observation nodes were vertically deployed in the mooring system, with ADCP current profilers, CTD sensors, and turbidity meters installed sequentially at different heights above the seabed. Each sensor continuously collected data on current velocity, temperature, salinity, pressure, and turbidity at preset time intervals (e.g., 1 minute), with an observation period of one year.

[0108] After data acquisition, the various observation data were first processed for time synchronization, outlier removal, and vertical position correction to obtain a quality-controlled multi-source mooring observation dataset. Subsequently, using temperature, salinity, and pressure data acquired by the CTD (Conductivity, Tolerance, and Difference) system, the background seawater density profile was calculated based on the seawater state equation. Simultaneously, combined with turbidimeter observations, the additional influence of suspended particles on density was corrected to construct an equivalent density profile during turbidity currents. Based on this, the vertical gradient of the equivalent density was calculated using the adjacent measuring point difference method, further obtaining the stratification intensity parameters of the water body during turbidity currents.

[0109] Meanwhile, using velocity profile data acquired by ADCP, the vertical velocity shear intensity was calculated by differential analysis of adjacent measuring points. This calculation was then combined with stratification intensity parameters at corresponding times and heights to construct the temporal and vertical distribution of the gradient Richardson number. Analysis of the gradient Richardson number variation characteristics identified key periods and height ranges during turbidity flow events characterized by weakened stratification, enhanced shear, and significant shear instability.

[0110] This embodiment enables continuous monitoring of water stratification and mixing state during deep-sea turbidity currents under moored observation conditions, and effectively identifies high-risk layers associated with strong mixing processes in turbidity currents, providing reliable data support and technical means for environmental assessment and disaster risk monitoring of deep-sea engineering facilities.

[0111] This invention discloses a method for measuring and calculating the stratification intensity within deep-sea turbidity currents. It effectively integrates multi-source asynchronous observation data such as velocity, temperature, salinity, and turbidity under discrete moored observation systems, enabling quantitative calculation of water stratification intensity during deep-sea turbidity currents. By introducing the influence of suspended sediment concentration on density to construct an equivalent density parameter, it overcomes the limitations of traditional stratification intensity calculation methods that rely on static stability assumptions and high-resolution continuous profiles, making it applicable to unsteady turbidity current environments with high suspended sediment and strong shear. Furthermore, this invention combines the calculated vertical velocity shear to construct a gradient Richardson number, thereby effectively characterizing the relative relationship between stratification and shearing during turbidity current processes and identifying key periods and layers of shear instability and enhanced mixing. This method does not require high-frequency microstructure observation equipment and can be implemented based on conventional moored observation data, providing a highly feasible and easily promoted technical means for the study of deep-sea turbidity current dynamic processes and disaster risk monitoring of seabed engineering facilities.

[0112] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for measuring and calculating the stratification intensity within deep-sea turbidity currents, characterized in that, include: Based on the vertically deployed anchored observation system, multi-source observation data of water velocity, temperature, salinity, pressure and turbidity at different depths are obtained; The multi-source observation data is preprocessed for time synchronization and spatial stratification matching to form a time-space aligned joint dataset; Based on the preprocessed turbidity and flow velocity data, the time periods of turbidity events are identified; Based on temperature, salinity, pressure, and turbidity data during the period of the turbidity event, an equivalent density profile including the contribution of suspended sediment concentration was constructed. Based on the equivalent density profile, the stratification intensity parameters characterizing the stability of the water body are calculated; By combining the stratification intensity parameters with the vertical velocity shear of the corresponding time period and layer, the gradient Richardson number is calculated to analyze the mixing state inside the turbidity current.

2. The method for measuring and calculating the stratification intensity within deep-sea turbidity currents as described in claim 1, characterized in that, Acquiring multi-source observation data includes: The anchorage observation system is equipped with an acoustic Doppler current profiler, a temperature, salinity, and depth measuring instrument, a turbidity measuring instrument, and a sediment trap along its vertical direction. Among them, the temperature, salinity, depth and turbidity measuring instrument and the turbidity measuring instrument are set up on the same floor to collect temperature, salinity, pressure and turbidity data simultaneously; Acoustic Doppler current profilers are used to acquire flow velocity profile data; Sediment traps are used to obtain suspended sediment samples to calibrate the relationship between turbidity and suspended sediment concentration.

3. The method for measuring and calculating the stratification intensity within deep-sea turbidity currents as described in claim 1, characterized in that, The preprocessing of the multi-source observation data for time synchronization and spatial stratigraphic matching includes: Unify and correct the time base of data from different sensors, and resample all data to a uniform time resolution; The flow velocity data obtained by the acoustic Doppler current profiler is vertically matched with the temperature, salinity, depth and turbidity measurement data at the corresponding height. The matched data is smoothed to suppress high-frequency noise.

4. The method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in claim 1, characterized in that, The time periods during which turbidity events occur include: A sudden increase in turbidity data exceeding a preset threshold is used as a preliminary criterion; A secondary identification is performed by combining the significant increase in flow velocity and the vertical consistency of flow direction within the corresponding time period; By utilizing anomalous changes in temperature and salinity data to eliminate non-turbidity flow interference processes, the start and end times of turbidity flow events were ultimately determined.

5. The method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in claim 1, characterized in that, Constructing the equivalent density profile includes: Background seawater density was calculated using temperature, salinity, and pressure data; Turbidity data from sediment samples were calibrated, and suspended sediment concentration was obtained by inversion. The equivalent density is calculated by superimposing the contribution of suspended sediment concentration to the density on the background seawater density.

6. The method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in claim 5, characterized in that, The calculation of layering intensity parameters includes: The equivalent density profile is subjected to vertical difference to obtain the vertical gradient of the equivalent density. Substituting the vertical gradient into the formula for calculating the Brønsted-Weiser frequency yields the layering intensity parameter.

7. The method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in claim 1, characterized in that, Calculating the gradient Richardson number to analyze the internal mixing state of turbidity flows includes: Based on the velocity profile data during the period of the turbidity event, the vertical velocity shear is calculated; Divide the stratification intensity parameter by the vertical velocity shear at the corresponding time and layer to obtain the gradient Richardson number; Based on the numerical range of the Richardson number, the stability of the water body and the conditions for the development of turbulent mixing are determined.

8. The method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in claim 1, characterized in that, The vertically deployed anchorage observation system includes: A combination sensor of temperature, salinity and turbidity measuring instrument is fixedly installed at different heights along the vertical from bottom to top on the anchoring rope; An acoustic Doppler current profiler is installed at a preset height from the bottom. An acoustic release device and a counterweight are installed at the bottom of the anchor system, and a buoy to provide buoyancy is connected at the top.

9. An electronic device, characterized in that, The electronic device includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, it implements the method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in any one of claims 1-8.

10. A computer storage medium, characterized in that, The computer storage medium stores computer program instructions, which, when executed by a processor, implement the method for measuring and calculating the stratification intensity inside deep-sea turbidity currents as described in any one of claims 1-8.

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