River reach division method and device based on radial flux, electronic equipment and storage medium

Abstract

The invention belongs to the technical field of hydrological monitoring, and provides a river reach division method and device based on radial flux, electronic equipment and a storage medium, and the method comprises the steps: obtaining digital elevation model data of a to-be-analyzed region; performing data processing on the digital elevation model data to obtain a confluence accumulation grid map which is a grid map of a river reach in the to-be-analyzed area; on the basis of the confluence accumulation grid map, the river reach is divided, a plurality of equal-flux river reaches and a plurality of unequal-flux river reaches are obtained, and the equal-flux river reaches are used for analyzing the river reaches. According to the invention, the influence of the river section with unstable flow flux on the monitoring precision of the flow flux of the river channel is eliminated.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrological monitoring, and in particular relates to a method, device, electronic equipment and storage medium for dividing a river section based on runoff flow. Background Art

[0002] River flow is one of the core parameters in the hydrological cycle. It not only affects the water balance, but also is the key basis for decision-making on water resources management and ecological and environmental protection. At present, flow monitoring mainly relies on ground hydrological stations. Ground hydrological stations are usually set up in river sections with relatively stable flow. By monitoring cross sections, high-precision flow monitoring is achieved. Ground hydrological stations will also record runoff flow data accordingly. Runoff flow refers to the amount of water passing through a cross section in a certain period of time. The period can be years, months, days, etc. However, in areas with complex terrain and inconvenient transportation such as high mountains and canyons, the construction and maintenance costs of hydrological stations are high, and the distribution of stations is often sparse, resulting in limited monitoring coverage and the inability to conduct systematic monitoring of river runoff flow.

[0003] In order to solve the problem that the monitoring range cannot be fully covered, remote sensing technology is usually introduced. Remote sensing technology has the advantages of wide spatial coverage, convenient data acquisition, and multi-temporal. Flow monitoring based on remote sensing can provide effective data support in areas where ground hydrological stations are lacking, and is especially suitable for large-scale and multi-regional runoff flow monitoring. However, under normal circumstances, the runoff flow of some river sections in the river channel is relatively unstable, while the runoff flow of some river sections is relatively stable. The remote sensing image data of the less stable river sections will affect the runoff flow monitoring of the entire river channel. Therefore, how to eliminate the impact of unstable runoff flow sections on the accuracy of river runoff flow monitoring is an urgent problem to be solved in this field. Summary of the invention

[0004] To solve the above problems, the present disclosure provides a method, device, electronic device and storage medium for river section division based on runoff flux, which aims to eliminate the influence of river sections with unstable runoff flux on the accuracy of river runoff flux monitoring.

[0005] In order to achieve the above objectives, the present disclosure mainly provides the following technical solutions:

[0006] In a first aspect, the present disclosure provides a river section division method based on runoff flux, comprising:

[0007] Obtain digital elevation model data of the area to be analyzed;

[0008] Processing the digital elevation model data to obtain a runoff accumulation grid map, wherein the runoff accumulation grid map is a grid map of the river section in the area to be analyzed;

[0009] Based on the confluence accumulation grid map, the river section is divided to obtain a plurality of equal-flux river sections and a plurality of unequal-flux river sections, and the equal-flux river sections are used to analyze the river section.

[0010] In a second aspect, the present disclosure provides a river section division device based on runoff flux, the device comprising:

[0011] An acquisition unit, used for acquiring digital elevation model data of the area to be analyzed;

[0012] A data processing unit, used for performing data processing on the digital elevation model data to obtain a runoff accumulation grid map, wherein the runoff accumulation grid map is a grid map of the river section in the area to be analyzed;

[0013] A division unit is used to divide the river section based on the confluence accumulation grid map to obtain multiple equal-flux river sections and multiple unequal-flux river sections, and the equal-flux river sections are used to analyze the river section.

[0014] On the other hand, the present disclosure also provides a storage medium, which is used to store a computer program, wherein when the computer program is running, it controls the device where the storage medium is located to execute the river section division method based on runoff flux in the above-mentioned first aspect.

[0015] On the other hand, the present disclosure also provides an electronic device, comprising at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other through the bus; and the processor is used to call program instructions in the memory to execute the river section division method based on runoff flux as described in the first aspect above.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The present disclosure obtains digital elevation model data of the area to be analyzed, and after data processing of the digital elevation model data, obtains a cumulative grid map of the runoff of the river section in the area to be analyzed. Since the cumulative runoff number of the grid in the cumulative runoff grid map indicates the cumulative amount of water flow at each point in the river section, based on the cumulative runoff grid map, the river section with a smaller change in runoff flux in the river section can be selected from the entire river section to obtain a plurality of equal-flux river sections, thereby determining the remaining river sections that are not equal-flux river sections in the river section as a plurality of unequal-flux river sections. The present disclosure selects a river section with a stable runoff flux, i.e., an equal-flux river section, from the entire river section. When analyzing the runoff flux of the entire river section, the remote sensing image data of the equal-flux river section is used for analysis, thereby eliminating the influence of the unstable runoff flux river section on the monitoring accuracy of the river section runoff flux.

[0018] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of a flow chart of a river section division method based on runoff flux according to an embodiment of the present disclosure is shown;

[0021] Figure 2 A schematic diagram showing a flow chart of the river section division step according to an embodiment of the present disclosure is shown;

[0022] Figure 3a A remote sensing image of a river section with equal flux including the Zhimenda hydrological station according to an embodiment of the present disclosure is shown;

[0023] Figure 3b A remote sensing image of a river section with equal flux including the Gangtuo hydrological station according to an embodiment of the present disclosure is shown;

[0024] Figure 3c The isoflux river section remote sensing image containing the Batang hydrological station according to an embodiment of the present disclosure is shown;

[0025] Figure 3d A remote sensing image of a river section with equal flux including the Benzilan hydrological station according to an embodiment of the present disclosure is shown;

[0026] Figure 3e A remote sensing image of an isoflux river section including the Shigu hydrological station according to an embodiment of the present disclosure is shown;

[0027] Figure 4 A schematic structural diagram of a river section division device based on runoff flux according to an embodiment of the present disclosure is shown;

[0028] Figure 5 A schematic diagram of the structure of an electronic device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0030] In the process of using remote sensing technology to systematically monitor the runoff flow of river sections, the remote sensing image data of river sections with relatively unstable runoff flow will affect the monitoring of the runoff flow of the entire river section. Specifically, satellites periodically take remote sensing images of various regions, which means that it is impossible to continuously monitor the runoff flow of river sections. The flow rate of river sections with unstable runoff flow varies greatly (sometimes the flow rate is small, sometimes the flow rate is large). If the satellite repeatedly captures the unstable runoff flow river section in a state of large flow, the runoff flow monitoring of the river section based on this part of the remote sensing image will deviate from the actual runoff flow value of the river section. Therefore, the remote sensing image of the river section with unstable runoff flow will reduce the accuracy of the overall runoff flow monitoring of the river section.

[0031] Based on this, the embodiment of the present disclosure provides a river section division method based on runoff flow, such as Figure 1 As shown, the river section division method based on runoff flux in the embodiment of the present disclosure includes:

[0032] 101. Obtain digital elevation model data of the area to be analyzed.

[0033] Among them, the digital elevation model (DEM) is a digital simulation of the ground terrain through limited terrain elevation data. The digital elevation model data in the embodiment of the present disclosure can be the 30m resolution Copernicus DEM data released by ESA and AIRBUS in 2021.

[0034] In this step, for the river section to be analyzed, the area to be analyzed containing the river section is determined, and corresponding digital elevation model data is obtained based on the area to be analyzed.

[0035] 102. The digital elevation model data is processed to obtain a runoff accumulation grid map, which is a grid map of the river section in the area to be analyzed.

[0036] The confluence accumulation grid map is used to display the river network in the area to be analyzed. The river network is composed of basins and sub-basins. The basin is the main stream in the river network, and the river section in the embodiment of the present disclosure is a part of the main stream. The river network is composed of a large number of grids, and each grid corresponds to a confluence accumulation number. The confluence accumulation number is the accumulated amount of water flow.

[0037] In this step, based on the digital elevation model (DEM) data, firstly, unreasonable depressions are eliminated by filling the depressions to generate a depression-free elevation model; then, the D8 algorithm is used to calculate the water flow direction of the grid unit, and the upstream water flow is accumulated based on the flow direction data to generate a confluence accumulation grid map; the main water flow path is extracted according to the set confluence threshold, and the river network raster data is generated and vectorized and graded; finally, the watershed boundary and pouring point are determined through watershed analysis, and the small watershed is divided based on the pouring point to generate a watershed and river network distribution map

[0038] 103. Based on the confluence accumulation grid map, the river section is divided to obtain multiple equal-flux river sections and multiple unequal-flux river sections, and the equal-flux river sections are used to analyze the river section.

[0039] Among them, the isoflux river section is the river section with stable runoff flux in the entire river section to be analyzed. When the runoff flux of the river section is systematically monitored, the runoff flux of the entire river section can be accurately monitored by monitoring and analyzing the runoff flux of each isoflux river section. The unequal flux river section is the river section with unstable runoff flux in the entire river section to be analyzed.

[0040] In this step, N reference points can be determined on the river section in the confluence accumulation grid map, and for each reference point, the confluence accumulation number corresponding to the reference point is determined. In the upstream and downstream directions of the reference point, two points with a change amplitude of the confluence accumulation number of a preset amplitude are respectively found, and the upstream point is determined as the entrance point of the equal flux river section, and the downstream point is determined as the exit point of the equal flux river section, so as to determine an equal flux river section. After determining N equal flux river sections, the river sections of the entire river section except the N equal flux river sections are determined as multiple unequal flux river sections.

[0041] The disclosed embodiment obtains the digital elevation model data of the area to be analyzed, and after data processing the digital elevation model data, obtains the runoff accumulation grid map of the river section in the area to be analyzed. Since the runoff accumulation number of the grid in the runoff accumulation grid map indicates the accumulated amount of water flow at each point in the river section, based on the runoff accumulation grid map, the river section with a smaller change in runoff flux in the river section can be selected from the entire river section to obtain a plurality of equal-flux river sections, thereby determining the remaining river sections in the river section that are not equal-flux river sections as a plurality of unequal-flux river sections. The disclosed embodiment selects a river section with a stable runoff flux, i.e., an equal-flux river section, from the entire river section. When analyzing the runoff flux of the entire river section, the remote sensing image data of the equal-flux river section is used for analysis, thereby eliminating the influence of the unstable runoff flux on the monitoring accuracy of the river section runoff flux. Therefore, the disclosed embodiment also improves the monitoring accuracy of the runoff flux of the entire river section.

[0042] In order to explain in detail the river section division method based on runoff flow proposed in the present disclosure, the river section division steps are described in detail below. Figure 2 As shown, the details are as follows:

[0043] 201. Determine multiple benchmark points in the runoff accumulation grid map.

[0044] The benchmark point is located in the river section. The benchmark point is a point on the river section in the confluence accumulation grid map, and each benchmark point corresponds to a grid.

[0045] In this step, multiple benchmark points are determined in the runoff accumulation grid map, and the equal flux river sections containing the benchmark points can be determined based on the benchmark points. The number and location of the benchmark points can be selected according to the actual scenario. For example, if the river section is long, the number of benchmark points can be large. It is also possible to determine each hydrological station or part of the hydrological stations on the river section in the area to be analyzed as benchmark points.

[0046] In one achievable manner, the specific implementation of determining the reference point is as follows:

[0047] Step 1: Use digital elevation model data to obtain the location information of each hydrological station in the river section.

[0048] In the disclosed embodiment, the digital elevation model data has all geographic information of the area to be analyzed, and correspondingly, the location information of each hydrological station monitoring the river section within the area to be analyzed is also recorded in the digital elevation model data.

[0049] Step 2: According to the location information, determine the corresponding reference point in the confluence accumulation grid map.

[0050] In this step, after obtaining the location information of all hydrological stations monitoring the river section based on the digital elevation model data, the grid corresponding to the hydrological station can be determined using the location information of the hydrological station and the correspondence between the location information and the corresponding grid in the confluence accumulation grid map. The position of the grid is the position of the reference point.

[0051] The disclosed embodiment determines each hydrological station in a river section as a reference point. Since the hydrological station itself monitors and records hydrological data, such as flow rate and other data, the hydrological data of the hydrological station itself can be conveniently used to verify the river section runoff flow monitoring data (remote sensing image) so as to further improve the accuracy of the river section runoff flow monitoring.

[0052] 202. Multiple equal flux river sections are determined by using multiple benchmark points and the cumulative runoff of each grid in the runoff accumulation grid map.

[0053] Among them, the grid is the component unit of the runoff accumulation grid map, and all grids outline the entire river network in the area to be analyzed. Each grid has a runoff accumulation number. The runoff accumulation number is the accumulated amount of water flow. One benchmark point corresponds to an isoflux river section.

[0054] In this step, by using data conversion and spatial analysis tools, the cumulative runoff of each grid cell is calculated and obtained. The cumulative runoff of the entire river section can be statistically analyzed to determine the changing trend of the cumulative runoff in the river section. Based on the changing trend and the selected benchmark points, multiple equal flux river sections can be determined.

[0055] In one practicable manner, the specific implementation method of determining the isoflux river section is as follows:

[0056] Step 1: Use the cumulative runoff and its area of ​​each grid in the runoff accumulation grid map to obtain the runoff intensity of each grid.

[0057] Among them, the water catchment intensity is used to indicate the water catchment capacity of the corresponding grid.

[0058] In this step, the product of the accumulated runoff of the grid and the area of ​​the grid can be determined as the water collection intensity of the grid, or the product of the accumulated runoff of the grid, the area and the rainfall can be determined as the water collection intensity of the grid.

[0059] Exemplarily, the water harvesting intensity is determined as follows:

[0060] Step 1a: multiply the grid's cumulative flow accumulation by the grid's area to obtain the grid's flow accumulation area.

[0061] The formula for catchment area is as follows:

[0062] A = cumulative flow × grid area

[0063] Where A is the confluence area, m 2 .

[0064] Step 1b: Determine the catchment area as the catchment intensity of the grid.

[0065] Exemplarily, another way to determine the water harvesting intensity is as follows:

[0066] Step 1a: multiply the accumulated flow of each grid by the corresponding area to obtain the flow area of ​​each grid.

[0067] Step 1b: Obtain rainfall data for the area to be analyzed.

[0068] In this step, satellite remote sensing rainfall data can be used to perform spatial interpolation of large-scale rainfall to obtain rainfall data for the area to be analyzed. And the satellite remote sensing rainfall data can be corrected by collecting rainfall station data in the area to be analyzed through the China Meteorological Network to ensure more accurate rainfall data.

[0069] Step 1c: Generate a rainfall distribution map based on rainfall data, use the rainfall distribution map to obtain the normalized rainfall weight of each grid, and calculate the initial flow of the corresponding grid based on the normalized rainfall weight.

[0070] The area of ​​each cell is the same, which is the unit area, and the unit is m 2 .

[0071] In this step, the rainfall data is the multi-year average rainfall, which is matched with the DEM data through spatial interpolation to ensure the consistency of spatial resolution. The obtained multi-year average rainfall distribution map needs to be normalized to serve as the weight file for the runoff accumulation calculation.

[0072] Specifically, the inverse distance weighted (IDW) method can be used to spread the point rainfall to the entire river network to generate a surface rainfall distribution map. The rainfall formula for the interpolation point in the surface rainfall distribution map is as follows:

[0073]

[0074] Where P (x，y) The rainfall at the point to be interpolated, mm, P i The rainfall at the i-th observation station, mm, d i The distance between the point to be interpolated and the i-th observation site, m, p represents the power of the distance, usually 2 represents inverse square weighting.

[0075] Generate rainfall distribution map: Save the rainfall data generated by IDW interpolation in raster format to generate the spatial distribution map of multi-year average rainfall.

[0076] Normalization of rainfall distribution map:

[0077] Purpose: To normalize the generated rainfall distribution map so that it can be used as a weight file for runoff accumulation calculation, so that the rainfall data has a uniform dimension in spatial distribution. The normalized rainfall distribution map obtained is used as a weight file for runoff accumulation calculation.

[0078] Normalization of rainfall:

[0079]

[0080] Among them, W i，jis the normalized rainfall weight, G i，j The average annual rainfall of the grid, P min and P max They are the minimum and maximum rainfall in the rainfall distribution map, respectively.

[0081] 1. Calculate the initial flow of each grid

[0082] G per grid i The initial sink flow is:

[0083] P i，j =W i，j ×R×A i，j

[0084] Where P i，j G i，j Rainfall per cell, mm, W i，j is the corresponding normalized rainfall weight, mm, and R is the multi-year average maximum rainfall depth in the region (usually in millimeters or meters), which is used to convert the weight value into a specific rainfall depth. i，j is the area of ​​the grid, km 2 .

[0085] Step 1d: Perform slope analysis based on DEM data and generate a slope raster map.

[0086] Slope calculation: Perform slope analysis based on DEM data to generate slope raster data for simulating water flow paths and determining confluence relationships.

[0087] The DEM data is used to perform slope analysis to obtain the flow direction of each grid. The commonly used D8 algorithm (each grid flows to one of the eight adjacent grids around it) is used to calculate the slope and generate a slope grid map.

[0088] Step 1e: Calculate the total flow of the grid using the aspect grid map and the initial flow of the grid.

[0089] Confluence accumulation calculation: The flow is accumulated from the upstream grid to the downstream grid according to the aspect map.

[0090] The total flow rate of each grid is Q i，j Including its own rainfall sink P i，j And the flow rate transmitted from the upstream grid. The formula is as follows:

[0091]

[0092] In the formula, Q i，j is the grid G i，j Total sink flow; P i，j G i，jThe initial flow rate of the grid; U i，j is the total grid G i，j The upstream grid collection of the confluence; Q m，n is the upstream grid G m，n The cumulative flow of m，n is the flow scale factor, representing the upstream grid G m，n The water reaches the downstream grid G i，j proportion.

[0093] Aspect weight f m，n :

[0094] Determine the flow ratio: If there are more than one downstream grids flowing from each upstream grid, you need to allocate the flow ratio. Assume that the flow is evenly distributed to all downstream grids:

[0095]

[0096] Step 1f: Determine the total catchment flow as the catchment intensity of the grid.

[0097] Step 2: Determine the grid where the reference point is located in the confluence accumulation grid map to obtain the first grid.

[0098] Step 3: Starting from the first grid, search for the second grid upstream of the first grid.

[0099] The variation range of the water collection intensity of the second grid is the same as that of the first grid and the preset range. For example, assuming the preset range is 5%, the water collection intensity of the first grid is 100, and the water collection intensity of the second grid is 95 or 105.

[0100] In this step, starting from the first grid, the second grid is searched along the upstream of the first grid, that is, along the upstream of the river section. For example, a grid with a water collection intensity change of 5% can be searched along the upstream direction of the first grid, and the grid is determined as the second grid.

[0101] Step 4: Starting from the first grid, search for the third grid downstream of the first grid.

[0102] The variation range of the water collection intensity of the third grid and the water collection intensity of the first grid is the same as the preset range.

[0103] Step 5: Use the position information of the second grid and the position information of the third grid to determine the isoflux river section corresponding to the reference point.

[0104] In order to more clearly illustrate the method of determining multiple equal flux river sections, the upper reaches of the Jinsha River are used as an example:

[0105] The upper reaches of the Jinsha River are from Zhimenda Hydrological Station to Shigu Hydrological Station. Taking each hydrological station as a benchmark, the Zhimenda Hydrological Station is taken as an example. The confluence area of ​​the Zhimenda Hydrological Station is 9553.14 km 2 , find the location where the catchment area changes by 5% upstream and downstream (until the basin boundary), obtain the upstream and downstream entrance points, and measure the length of the river section as shown in Table 1. The isoflux river section containing the Zhimenda hydrological station is shown in Figure 3a As shown in Figure 2, the isoflux river section containing the Gangtuo hydrological station is as follows: Figure 3b As shown in Figure 2, the isoflux river section containing the Batang hydrological station is as follows: Figure 3c As shown in Figure 2, the isoflux river section containing the Benzilan hydrological station is as follows: Figure 3d As shown in Figure 2, the isoflux river section containing the Shigu hydrological station is as follows: Figure 3e shown.

[0106]

[0107] Table 1 Relevant information of multiple isoflux river sections in the upper Jinsha River

[0108] Eliminate all river sections with equal flux in the river section to obtain multiple river sections with unequal flux.

[0109] The embodiment of the present disclosure selects river sections with equal flux in the entire river section based on rainfall data and the cumulative number of confluence of each grid. The introduction of rainfall data makes the hydrological data in the river section more accurate. Therefore, the embodiment of the present disclosure more accurately selects river sections with stable runoff flux.

[0110] The embodiment of the present disclosure can also divide the river section with daily stable flux in the river section with equal flux, and the specific implementation method is as follows:

[0111] Data collection steps:

[0112] 1. Data Collection

[0113] (1) Remote sensing image collection: Select appropriate remote sensing data sources (such as Landsat, Sentinel, Gaofen, etc.) to collect multi-source remote sensing images for 30 consecutive years to obtain multi-temporal images of the study area in different hydrological periods.

[0114] (2) Collection of altimetry satellite data: Collection of altimetry satellite data from the past 30 years, including TOPEX / Poseidon, Envisat, CryoSat-2, I CE Sat series, Jason series, Sentinel-3 and Gaofen series.

[0115] (3) Hydrological data: Daily flow, water level data, and large-section data of the basin are obtained based on the hydrological yearbook published by the Ministry of Water Resources for use in hydrological analysis and model verification.

[0116] 2. Preprocessing

[0117] (1) Image preprocessing: Perform radiation correction, geometric correction, atmospheric correction and other operations to ensure image accuracy and consistency and provide accurate basic data for subsequent river section analysis.

[0118] Steps to construct river terrain:

[0119] 1. Extract waterside lines based on remote sensing images

[0120] Optical remote sensing data was used to obtain river water morphology information under different water level conditions over the past 30 to 40 years, extract the NDW l of the water body, form a water body surface vector file, and obtain the water edge vector file.

[0121]

[0122] Wherein, NDWI is the normalized water index, Green is the green light band, and NIR is the near infrared band.

[0123] The water body boundary is extracted through NDW I to form a river water body vector file.

[0124] 2. Divide the oscillating river section and the stable river section

[0125] (1) Obtain the river centerline at different times.

[0126] (2) Calculation of mainstream migration parameters

[0127] According to the water body vector range and the river centerline at different periods, the 500m river section spacing is selected to obtain the water surface width, and the position of the intersection of the section and the centerline is obtained. The migration distance of the intersection at different periods is measured as s, and the migration speed v and acceleration a are obtained in turn.

[0128] First, calculate the water surface width and migration distance s, merge the center lines of the two river sections in different periods, and then obtain the migration distance through measurement. The migration speed is the ratio of the migration distance to the time, and the migration acceleration is the ratio of the migration speed to the time.

[0129] (3) Calculation of RSIRR-GG relative stability index

[0130] The RSIRR-GG index can be regarded as a linear combination of the mainstream line migration distance s, velocity v, and acceleration a. The formula is as follows:

[0131] RSIRR-GG=β1s+β2v+β3a

[0132] Among them, β1, β2, and β3 are undetermined coefficients, which contain the change information of the river during the time interval Δt.

[0133] The steps to determine the coefficient values ​​in the above formula using cluster analysis are as follows:

[0134] Step 1: Extract morphological indicators, including mainstream migration distance and channel width at the cross section (assuming the cross section is N), and calculate the values ​​of mainstream migration distance s, velocity v, and acceleration a.

[0135] Step 2: Cluster analysis. Since the number of groups g is unknown, the hierarchical clustering method is used to divide the above N sections into g groups based on three indicators (mainstream migration distance s, velocity v, and acceleration a), and the appropriate number of groups g is estimated. Then, the clustering results are calculated based on the similarity distance between the N sections and the natural grouping process.

[0136] Step 3: Calculate the F statistic for the above three indices. F is defined as the ratio of the sum of the variances to the sum of the between-group error variances.

[0137]

[0138]

[0139]

[0140] Where SS(TR) is the sum of squares between groups, SSE is the error sum of squares, g is the degrees of freedom, i.e. the number of classification groups; n i is the number of cross sections in the i-th group; x i and x are the average index values ​​of the cross sections of group i and all groups, respectively; x ij is the index value of the jth segment in the i-th group.

[0141] The indicator F can be regarded as the weight of β1, β2, and β3:

[0142] F1:F2:F2=β1:β2:β3

[0143] Step 4: Threshold determination. After determining the three coefficients, calculate RSIRR-G on each cross section according to formula (4-7), and select the maximum RSIRR-G for each group. max，i and minimum RSIRR-G min，i (i=1, 2, ..., g). Since the RSIRR-G threshold between two adjacent groups can be in the interval [RSIRR-G max，I ,RSIRR-G min，i+1 ] is considered, so if the interval is small, an approximate constant in the interval is given to replace the true value of the threshold.

[0144] (4) Divide river sections into stable river sections and swinging river sections

[0145] Extend the RSI RR-G from the cross-section scale to the reach scale. The RSI RR at the reach scale is equal to the average value of the RSI RR-G of all cross-sections in the reach.

[0146]

[0147] 3. Identify meandering reaches and straight reaches

[0148] Based on the centerline of the river channel and the meandering degree of the reach, determine whether the reach is a straight reach or a meandering reach according to the magnitude of the meandering degree.

[0149]

[0150] In the formula, s is the meandering degree of the reach, L is the length of the reach, in m; l is the straight-line distance between the two ends of the reach, in m;

[0151] According to Rosge's meandering degree classification system, rivers can be classified into the following categories: those with a meandering degree (s) less than or equal to 1 are straight channels; those with 1 < s ≤ 1.2 are low-meandering channels; those with 1.2 < s ≤ 1.5 are medium-meandering channels; and those with s greater than 1.5 are high-meandering channels.

[0152] 4. Data collection and spatio-temporal consistency calibration

[0153] Collect basic data: Collect daily water level monitoring information of hydrological stations, and obtain data from Jason series or other high-resolution altimetry satellites, and clarify the start time and time resolution of the data.

[0154] Spatio-temporal alignment: Calibrate the remote sensing images and altimetry data according to the acquisition time and spatial position to ensure that the position of the river channel water body in the image is consistent with the elevation data provided by the altimetry satellite.

[0155] Table 1 Common parameters related to altimetry satellites

[0156]

[0157]

[0158] Table 2 Common parameters related to optical satellites

[0159]

[0160] Based on multi-source remote sensing images and altimetry satellite data, the waterlines corresponding to the lowest and highest water levels of the reach can be accurately extracted, and the corresponding elevation information can be calculated based on the water level data.

[0161] 5. Assign elevation information to the waterline

[0162] The footprint of an altimeter satellite, that is, the coverage area of ​​the altimeter satellite, is generally large. Multiple points along the orbit direction can be formed within a footprint on a wide water surface. The linear equations fitted by these points are used to assign elevation values ​​to the intersection points with the water edge.

[0163] Straight river section processing: For relatively straight river sections, the elevation values ​​of the intersection points of the waterside lines are equal along the center line, so the elevation information provided by the altimetry satellite can be directly assigned. The points corresponding to the elevation values ​​are extracted by intersecting the centerline vertical line with the waterside line.

[0164] Curved river section processing: In a curved river section, the elevation of the waterside line and the center line may be different. In this case, the elevation values ​​of the altimetry satellite are used to perform linear fitting along the river channel to obtain continuous elevation changes. Elevation values ​​are assigned at the intersection points of the waterside lines through fitting, thereby more accurately reflecting the terrain changes of the curved river channel.

[0165] 6. Generate contour lines

[0166] (1) Interpolation calculation of waterside elevation points

[0167] Interpolation calculations are performed on the elevation points of the waterside to generate continuous elevation data along the river. Spline interpolation or Kriging interpolation methods are used to smoothly extend the discrete waterside elevation points to ensure the integrity of the elevation data in the river. The elevation surface generated in this way effectively fills the elevation gaps and is particularly suitable for curved river sections with significant terrain changes.

[0168] (2) Connect contour points to generate contour lines

[0169] On the interpolated elevation data, points of the same elevation (isoheight points) are identified along the waterline and these isoheight points are connected to generate contour lines.

[0170] Based on the waterside elevation data under different water level conditions, multiple contour lines are generated to further characterize the morphological changes of the river cross section at different water levels.

[0171] (3) Refinement and application of contour lines

[0172] The generated contour lines are smoothed to ensure the fluidity of the contour lines, which is convenient for subsequent applications in river section morphology recognition and flow estimation.

[0173] 7. River terrain construction

[0174] (1) Data Integration

[0175] Contour data: Use the contour lines generated in the previous step as the elevation basis of the three-dimensional terrain.

[0176] Minimum area water edge line: Extract the water edge line (minimum water level boundary) under the lowest water level conditions throughout the year as the reference boundary of the lowest water level of the river.

[0177] Maximum water edge: Extract the water edge (maximum water level boundary) under the highest water level conditions throughout the year and mark the maximum extension range of the river. (GF-7 stereo image pair)

[0178] (2) Underwater terrain construction

[0179] Generate underwater terrain based on minimum area water edges.

[0180] (3) Water terrain construction

[0181] Based on the maximum area water edge line, the water terrain is generated through the high-resolution 7 stereo image pair. The specific approach is: orthorectification and image fusion are performed to generate high-resolution orthophotos, and DSM and point cloud data are extracted based on the SuperView-1 stereo image pair data.

[0182] (4) Constructing a 3D terrain model

[0183] Elevation interpolation: Based on the contour line and water edge data, elevation interpolation is performed along the river channel to generate elevation data from the lowest water level to the highest water level to form a continuous elevation surface.

[0184] Boundary filling: Fill the elevation data between the minimum and maximum water edges, and use interpolation methods (such as TIN interpolation or Kriging interpolation) to generate continuous elevation values ​​to ensure seamless connection of the 3D model.

[0185] (5) Combine underwater terrain, river terrain, and surface terrain

[0186] The underwater terrain and river elevation data generated by the minimum water level boundary line and the surface terrain generated by the maximum water level boundary line are used for three-dimensional splicing. First, the underwater, river and surface elevation data are seamlessly connected along the cross-sectional direction based on the centerline of the river channel. TIN interpolation or Kriging interpolation is used to smoothly transition between the surface and underwater elevations to ensure the continuity and smooth boundaries of the three-dimensional model.

[0187] (6) Generate DEM

[0188] DEM construction: The interpolated elevation data is converted into a digital elevation model (DEM) to ensure that the three-dimensional terrain model covers the entire spatial area of ​​the river, including the river bank, riverbed, and the impact of seasonal changes in water level.

[0189] Resolution adjustment: According to monitoring requirements, adjust the resolution of DEM to ensure the accuracy and availability of the data and to meet the requirements of flow monitoring and cross-sectional morphology analysis.

[0190] After constructing the river topography of the isoflux river section, the water surface area of ​​the river section is obtained according to the topography and remote sensing, and the water surface area is superimposed on the topography to obtain the water surface gradient and cross-sectional area of ​​the river at this time. The water volume in the river at this time is obtained according to the "water surface area-reservoir capacity" curve, and the average flow velocity of the river is estimated based on the Manning formula. The "water surface area-reservoir capacity" curve is a curve generated by different water surface areas and corresponding water volumes.

[0191] The specific method of obtaining the average flow velocity is to use the Manning formula to estimate the average flow velocity of the river section according to the river topography.

[0192] The average flow velocity of the river section based on Manning's formula is:

[0193]

[0194] Where n is the Manning roughness coefficient; R is the hydraulic radius; S is the river slope.

[0195]

[0196] Where A is the cross-sectional area of ​​the river (m 2 ), and P is the wetted perimeter, which is the circumference of the water flow in contact with the riverbed (m). A larger hydraulic radius usually means less resistance to water flow, resulting in a higher flow rate.

[0197] Calculate the river slope based on DEM data:

[0198]

[0199] Where ΔH is the elevation difference between two points in the river, m; L is the length of the river, m.

[0200] The length of the river section with daily stable flux is calculated based on the average flow velocity, specifically:

[0201] On the basis of the isoflux river section, the river section with stable runoff flux on the daily scale is determined. The average flow velocity at point M on the isoflux river section is taken as the average flow velocity at point N where the average flow velocity changes on the isoflux river section on the daily scale. The river section at this time is the length of the river section with stable runoff flux on the daily scale.

[0202] Flow calculation on a daily scale:

[0203] The average flow velocity is calculated based on the water surface area at this time, and the time from point M to point N is calculated based on the water surface area of ​​the river section with stable runoff flux on a daily scale at this time and the length of the river section at this time.

[0204]

[0205] Where, t is the time from point M to point N (within 24 hours), s; L日 is the length of the river section with stable runoff flux at daily scale, m; is the average flow velocity, m / s;

[0206] Since the runoff flow in the river is stable, the river flow at this time is obtained based on the water surface area obtained by remote sensing:

[0207] According to the relationship between water surface area and reservoir capacity, the water volume V in the river section with stable runoff flux on a daily scale is obtained. According to the time from point M to point N, the flow rate of the river section with stable runoff flux on a daily scale is obtained.

[0208]

[0209] Where t is the time from point M to point N, s; Q is the flow rate of the river section with stable runoff flux on a daily scale, m 3 / s; V is the amount of water in the river section at the daily runoff steady flux, m 3 .

[0210] Based on the above method, the embodiment of the present disclosure provides a river section division device based on runoff flux, which is used to eliminate the influence of unstable runoff flux on the monitoring accuracy of river runoff flux. The embodiment of the device corresponds to the aforementioned method embodiment. For ease of reading, this embodiment will no longer repeat the details of the aforementioned method embodiment one by one, but it should be clear that the device in this embodiment can correspond to all the contents of the aforementioned method embodiment. Specifically, Figure 4 As shown, the device comprises:

[0211] An acquisition unit 31 is used to acquire digital elevation model data of the area to be analyzed;

[0212] A data processing unit 32 is used to process the digital elevation model data to obtain a runoff accumulation grid map, where the runoff accumulation grid map is a grid map of the river section in the area to be analyzed;

[0213] The division unit 33 is used to divide the river section based on the confluence accumulation grid map to obtain multiple equal-flux river sections and multiple unequal-flux river sections, and the equal-flux river sections are used to analyze the river section.

[0214] Furthermore, the division unit includes:

[0215] A first determination module is used to determine a plurality of reference points in the confluence accumulation grid map, wherein the reference points are located in the river section;

[0216] A second determination module is used to determine a plurality of isoflux river sections by using a plurality of the reference points and the cumulative flow of each grid in the cumulative flow grid map;

[0217] The elimination module is used to eliminate each equal flux river section in the river section to obtain multiple unequal flux river sections.

[0218] Furthermore, the first determining module is specifically configured to:

[0219] Using the digital elevation model data to obtain the location information of each hydrological station in the river section;

[0220] According to the position information, a corresponding reference point is determined in the flow accumulation grid map.

[0221] Furthermore, the second determining module is specifically configured to:

[0222] Using the accumulated flow number and area of ​​each grid in the accumulated flow grid diagram, the water intensity of each grid is obtained;

[0223] Determine the grid where the reference point is located in the confluence accumulation grid map to obtain a first grid;

[0224] Taking the first grid as a starting point, searching for a second grid upstream of the first grid, wherein the variation range of the water collection intensity of the second grid and the water collection intensity of the first grid is the same as the preset range;

[0225] Taking the first grid as a starting point, searching for a third grid along the downstream of the first grid, wherein the variation range of the water collection intensity of the third grid and the water collection intensity of the first grid is the same as the preset range;

[0226] The isoflux river section corresponding to the reference point is determined by using the position information of the second grid and the position information of the third grid.

[0227] Furthermore, the second determining module is further specifically configured to:

[0228] Performing a multiplication operation on the accumulated number of grid confluences and the area of ​​the grid to obtain the confluence area of ​​the grid;

[0229] The catchment area is determined as the water catchment intensity of the grid.

[0230] Furthermore, the second determining module is further specifically configured to:

[0231] Multiply the cumulative number of confluence of each grid and the corresponding area to obtain the confluence area of ​​each grid;

[0232] Acquire rainfall data of the area to be analyzed;

[0233] Based on the rainfall data, for each cell in the area to be analyzed, generate the rainfall amount of each cell;

[0234] Determine the rainfall amount of each grid using the rainfall amount and each grid;

[0235] For each grid, multiplying the confluence area of ​​the grid and the rainfall of the grid to obtain the cumulative flux intensity of the grid;

[0236] The accumulated flux intensity is determined as the water sink intensity of the grid.

[0237] Furthermore, the embodiment of the present disclosure also provides a processor, the processor is used to run a program, wherein the program executes the above Figure 1 -The method described in 3.

[0238] Furthermore, the embodiment of the present disclosure also provides a storage medium, wherein the storage medium is used to store a computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute the above Figure 1 -The method described in 3.

[0239] Furthermore, the present disclosure provides an electronic device 4, such as Figure 5 As shown, the device includes at least one processor 41, at least one memory 42 and a bus 43 connected to the processor 41; wherein the processor 41 and the memory 42 communicate with each other through the bus 43; the processor 41 is used to call the program instructions in the memory 42 to execute the above-mentioned river section division method based on runoff flow. The device in this article can be a server, a PC, a PAD, a mobile phone, etc.

[0240] Furthermore, the present disclosure also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that initializes the steps of the inspection method for network devices as described above.

[0241] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A river section division method based on runoff flux, characterized in that: The method comprises: Obtain digital elevation model data of the area to be analyzed; Processing the digital elevation model data to obtain a runoff accumulation grid map, wherein the runoff accumulation grid map is a grid map of the river section in the area to be analyzed; Based on the confluence accumulation grid map, the river section is divided to obtain a plurality of equal-flux river sections and a plurality of unequal-flux river sections, and the equal-flux river sections are used to analyze the river section.

2. The method according to claim 1, characterized in that Based on the confluence accumulation grid map, the river section is divided to obtain a plurality of equal flux river sections and a plurality of unequal flux river sections, including: Determine a plurality of reference points in the runoff accumulation grid map, wherein the reference points are located in the river section; Determine a plurality of isoflux river sections by using a plurality of the reference points and the cumulative flow of each grid in the cumulative flow grid map; In the river section, each equal flux river section is eliminated to obtain a plurality of unequal flux river sections.

3. The method according to claim 2, characterized in that A plurality of reference points are determined in the flow accumulation grid map, including: Using the digital elevation model data to obtain the location information of each hydrological station in the river section; According to the position information, a corresponding reference point is determined in the flow accumulation grid map.

4. The method according to claim 2, characterized in that: Determining a plurality of isoflux river sections by using the plurality of reference points and the cumulative flow of each grid in the cumulative flow grid map, including: Using the accumulated flow number and area of ​​each grid in the accumulated flow grid diagram, the water intensity of each grid is obtained; Determine the grid where the reference point is located in the confluence accumulation grid map to obtain a first grid; Taking the first grid as a starting point, searching for a second grid upstream of the first grid, wherein the variation range of the water collection intensity of the second grid and the water collection intensity of the first grid is the same as the preset range; Taking the first grid as a starting point, searching for a third grid along the downstream of the first grid, wherein the variation range of the water collection intensity of the third grid and the water collection intensity of the first grid is the same as the preset range; The isoflux river section corresponding to the reference point is determined by using the position information of the second grid and the position information of the third grid.

5. The method according to claim 4, characterized in that The water confluence intensity of each grid is obtained by using the cumulative confluence number and area of ​​each grid in the confluence accumulation grid map, including: Performing a multiplication operation on the accumulated number of grid confluences and the area of ​​the grid to obtain the confluence area of ​​the grid; The catchment area is determined as the water catchment intensity of the grid.

6. The method according to claim 4, characterized in that The water confluence intensity of each grid is obtained by using the cumulative confluence number and area of ​​each grid in the confluence accumulation grid map, including: Acquire rainfall data of the area to be analyzed; Generate a rainfall distribution map based on the rainfall data, obtain normalized rainfall weights of each grid using the rainfall distribution map, and calculate the initial sink volume of the corresponding grid based on the normalized rainfall weights; Perform aspect analysis based on DEM data and generate aspect raster map; Calculating the total flow of the grid using the aspect grid map and the initial flow of the grid; Determining the total sink flow as the sink intensity of the grid; The total flow formula is: In the formula, Q i,j is the grid G i,j Total sink flow; P i,j is the grid G i,j The initial sink flow; U i,j is the total grid G i,j The upstream grid collection of the confluence; Q m,n is the upstream grid G m,n The cumulative flow of m,n is the flow scale factor, representing the upstream grid G m,n The water reaches the downstream grid G i,j proportion.

7. The method according to claim 1, characterized in that The method further comprises: Constructing a river channel topography based on an isoflux river section, and calculating an average flow velocity of a river section according to the river channel topography; Determine point M on the river section with equal flux, and determine the average flow velocity at point M; Finding N points on the isoflux river section, where the average flow velocity at point M is consistent with the average flow velocity at point N on a daily scale; The river section between point M and point N is determined as the daily stable flux river section corresponding to the equal flux river section.

8. A river section division device based on runoff flow, characterized in that: The device comprises: An acquisition unit, used for acquiring digital elevation model data of the area to be analyzed; A data processing unit, used for processing the digital elevation model data to obtain a runoff accumulation grid map, wherein the runoff accumulation grid map is a grid map of the river section in the area to be analyzed; A division unit is used to divide the river section based on the confluence accumulation grid map to obtain multiple equal-flux river sections and multiple unequal-flux river sections, and the equal-flux river sections are used to analyze the river section.

9. The device according to claim 8, characterized in that The division units include: A first determination module is used to determine a plurality of reference points in the confluence accumulation grid map, wherein the reference points are located in the river section; A second determination module is used to determine a plurality of isoflux river sections by using a plurality of the reference points and the cumulative flow of each grid in the cumulative flow grid map; The elimination module is used to eliminate each equal flux river section in the river section to obtain multiple unequal flux river sections.

10. An electronic device, characterized in that: The device includes at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other through the bus; and the processor is used to call program instructions in the memory to execute the method described in any one of claims 1-7.

Images