A remote sensing hydrological station arrangement method

Abstract

The present disclosure relates to the technical field of remote sensing hydrological station layout, and provides a remote sensing hydrological station layout method, which comprises the following steps: selecting an equal-flux river section according to DEM data and satellite monitored rainfall data, extracting a water edge line of the equal-flux river section by means of remote sensing data, screening out a two-side or single-side open river section, and constructing a digital grid model DEM to obtain river channel topographic information of the river section; determining an open and semi-open typical river section from the selected river section, constructing a water surface area and storage capacity relationship curve, determining a unit river section length in combination with water quantity and area in different states, selecting a specific length of a typical observation river section in the typical river section, and laying out a remote sensing hydrological station to collect a remote sensing image of the typical observation river section, wherein the remote sensing image of the typical observation river section is used for calculating a river channel flow. The method can select a good typical observation river section and improve remote sensing observation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of remote sensing hydrological station deployment, and in particular to a remote sensing hydrological station deployment method. Background Art

[0002] Hydrological monitoring is a critical component of water resources management and flood prevention and disaster reduction. Traditional hydrological stations, as the primary means of obtaining hydrological information such as river flow, water levels, and rainfall, play a vital role in water resources surveys, planning, and scheduling. However, due to economic, social, and natural constraints, the density of hydrological stations in many river basins is currently low, particularly in high mountain valleys and remote areas, where a large number of rivers lack data. This phenomenon poses significant challenges to the comprehensive acquisition of hydrological information and river basin management.

[0003] The deployment and operation of traditional hydrological stations typically rely on infrastructure, equipment maintenance, transportation, and support from on-site personnel. Consequently, in areas with harsh natural conditions or inaccessible areas, the deployment and maintenance costs of traditional hydrological stations are extremely high, significantly impacting monitoring efficiency. Faced with these challenges, the existing hydrological station network is insufficiently dense, unable to provide comprehensive and timely data support for flood warning, scheduling, and flood prevention.

[0004] With the rapid development of remote sensing technology, remote sensing hydrological stations, as an emerging hydrological monitoring tool, provide important technical support for improving the wide-area coverage and timeliness of hydrological monitoring. Using high-resolution, short-revisit-period remote sensing satellites and drones, these stations enable contactless, dynamic monitoring of large-scale rivers, lakes, and other water bodies. This provides a new solution for obtaining hydrological information, particularly in data-free river areas where traditional hydrological stations are difficult to deploy.

[0005] However, although remote sensing technology has shown great potential in hydrological monitoring, the deployment and application of remote sensing hydrological stations still face many technical challenges.

[0006] First, there needs to be a reasonable balance between the spatial and temporal resolutions of different remote sensing data. High-resolution imagery can provide detailed river channel information, but its coverage is limited and its revisit period is long, making it difficult to meet the monitoring needs of rapid dynamic processes such as floods. Second, remote sensing imagery has limited applicability in complex terrain such as mountainous canyons. Factors such as mountain obstruction and undulating terrain can affect the acquisition and processing of remote sensing imagery. Third, the spatiotemporal dynamics of flood processes are complex, and remote sensing data at a single moment cannot fully capture the spatiotemporal evolution of floods. This is especially true in mountainous areas, where the propagation speed and path of floods are highly variable, making it difficult for traditional remote sensing data to meet timeliness requirements. Finally, issues such as the fusion and correction of multi-source remote sensing data and the interference of water surface reflection characteristics also place higher demands on the accuracy and monitoring effectiveness of remote sensing hydrological stations. Summary of the Invention

[0007] To address these issues, this paper provides a method for deploying remote sensing hydrological stations. Based on DEM and rainfall data, river sections with equal flux are selected. River topography is obtained by extracting water edges and constructing a digital grid model (DEM). Typical river sections are then selected. A relationship curve is constructed to determine the length of a unit river section, and typical observation sections are selected. Finally, remote sensing hydrological stations are deployed to collect remote sensing images for calculating river flow. This method can improve the accuracy and monitoring effectiveness of remote sensing hydrological stations.

[0008] The following is the technology of the present invention:

[0009] A method for deploying a remote sensing hydrological station, characterized by comprising:

[0010] Select equal-flux river sections based on DEM data and satellite-monitored rainfall data;

[0011] Based on remote sensing data, the waterfront of isoflux river sections is extracted, and river sections with open sides or one side are selected from these isoflux river sections. A digital grid model (DEM) of the river sections with open sides or one side is constructed based on the waterfront, and the DEM is used to obtain the river topography information of the river sections.

[0012] Select open and semi-open river sections from river sections with open sides or open on one side as typical river sections;

[0013] Based on the river topography information, a curve of the relationship between water surface area and reservoir capacity is constructed. The length of a unit river section is determined by combining the water volume and water surface area of ​​a typical river section under normal conditions and during floods. A river section with a length that is n times the length of the unit river section is selected as a typical observation river section.

[0014] Remote sensing hydrological stations are deployed to collect remote sensing images of typical observation river sections, and the remote sensing images of the typical observation river sections are used to calculate the river flow of the typical observation river sections.

[0015] Further,

[0016] Calculate the river flow of a typical observed river section, including:

[0017] Using remote sensing images of typical observed river sections, the multi-temporal water surface widths of multiple sections of the typical observed river sections are extracted; based on the multi-station hydraulic geometry of the typical observed river sections and the multi-temporal section water surface widths, the river flow is calculated.

[0018] Further,

[0019] The method is based on the multi-station hydraulic geometry relationship of a typical observed river section and the water surface width of a multi-phase section to calculate the river flow; including:

[0020] Initial cross sections are set at 500m intervals, and flow calculations are performed based on the hydraulic geometry relationship between flow and water surface width:

[0021] w=aQ b

[0022] Where, w is the width of the water surface, m; Q is the flow rate, m3 / s; a and b are hydraulic geometric parameters;

[0023]

[0024] Where x is the section number; w x is the average cross-sectional width, a x 、b x is the hydraulic geometric parameter of the x-th section; E is the specific parameter in the river channel;

[0025]

[0026] Where, is the water surface width of each section; p and y are fitting coefficients;

[0027] Measurements were taken at multiple fixed sections within the same river reach to establish a regression relationship between water surface width and discharge. The AMHG method was used to link river width and discharge at multiple sites through a log-linear relationship.

[0028] According to the value range of parameters a and b and the logarithmic linear relationship between a and b, the flow rate of any section can be calculated given a pair of a and b values ​​and the river width.

[0029] Further,

[0030] The values ​​of a and b are obtained using a genetic algorithm, which includes:

[0031] Given the initial value combination of hydraulic geometric parameters a and b;

[0032] The river flow is calculated using the initial value combination of hydraulic geometric parameters a and b and relevant river data. The calculated value is compared with the actual observed flow to obtain the fitness value.

[0033] Select the value combination of a and b with fitness higher than the threshold as the individual to enter the next generation population;

[0034] Perform crossover operations based on the next generation population and mutation operations to obtain a new population;

[0035] Iterate the new population to obtain the values ​​of hydraulic geometric parameters a and b.

[0036] Further,

[0037] The selection of equal flux river sections based on DEM data and satellite-monitored rainfall data includes:

[0038] Based on the DEM data, depression filling is performed to generate a depression-free DEM, calculate the water flow direction data and runoff accumulation, extract the watershed boundaries and river network, divide the watershed into levels based on the runoff accumulation number, and identify the main stream and tributaries of the runoff path; combine with rainfall data to obtain the runoff accumulation raster map;

[0039] From upstream to downstream of the river section, the runoff flow on the confluence path is calculated using the cumulative confluence grid map to determine the benchmark points, and the cumulative confluence of each grid and the changing trend of the river section are counted.

[0040] The locations where the cumulative flux intensity changes by 5% are identified, and the river sections where the change is within 5% are regarded as equal flux sections.

[0041] Further,

[0042] The method of extracting the water edge of an isoflux river section based on remote sensing data includes:

[0043] Extract river water morphology information from remote sensing image data;

[0044] Calculate the water body normalized index using different bands:

[0045]

[0046] Among them, Green and NIR are remote sensing reflectance of green band and near infrared band respectively;

[0047] Based on the normalized water index, multiple water edges and center lines at different times are extracted;

[0048] Draw a perpendicular line through the center line so that it intersects with the water's edge, and calculate the distance between the intersection points as the width of the water surface;

[0049] Calculate the average water surface width to obtain the average water surface width and determine the average water edge; compare the water surface widths to determine the maximum water edge and the minimum water edge.

[0050] Further,

[0051] The step of selecting a river section with open sides or one side from a river section with equal flux includes:

[0052] Calculating a first distance between the center line corresponding to the maximum water edge and the minimum water edge, and a second distance between the center line corresponding to the average water edge and the minimum water edge;

[0053] For the waterside lines on both sides of the river, calculate the moving distance ratio according to the formula (first distance - second distance) / second distance * 100%;

[0054] If the moving distance ratio of the water edges on both sides is <10%, the river section is a vertical section; if the moving distance ratio of the water edges on one side is <10% and the other side is ≥10%, it is a unilateral vertical and unilateral open section; if the moving distance ratio of the water edges on both sides is ≥10%, it is a bilateral open section, thus selecting the river section with open sides or unilateral open section.

[0055] Further,

[0056] The digital grid model DEM of the river section with open sides or one side based on the waterline is constructed, including:

[0057] Determine the water edge elevation value;

[0058] Extract multiple waterside lines and merge them to generate an outer envelope line. Interpolate the elevation values ​​on the waterside line within the maximum interpolation range based on the elevation value of the outer envelope line to obtain continuous elevation information.

[0059] Generate a digital grid model DEM of river terrain using continuous elevation information. The river terrain includes: underwater terrain, terrain from the maximum waterline to the minimum waterline, and terrain above the maximum waterline.

[0060] Further,

[0061] Determining the length of a unit river section includes:

[0062] Find the unit river section length l such that

[0063] Where ΔA i =A 1i -A 0i , A 1i A is the water surface area of ​​a unit river section when a flood occurs; 0i It is the water surface area of ​​a unit river section under normal conditions.

[0064] A method system for deploying remote sensing hydrological stations, characterized by comprising:

[0065] The selection module is used to select isoflux river sections based on DEM data and satellite-monitored rainfall data;

[0066] The river topography information acquisition module is used to extract the waterside lines of isoflux river sections based on remote sensing data, and select river sections with open sides or one side in the isoflux river sections; construct digital grid models (DEMs) of the river sections with open sides or one side based on the waterside lines, and use the digital grid models (DEMs) to obtain river topography information of the river sections;

[0067] Typical observation river section selection module, used to select open and semi-open river sections from river sections with open sides or open on one side as typical river sections;

[0068] Based on the river topography information, a curve of the relationship between water surface area and reservoir capacity is constructed. The length of a unit river section is determined by combining the water volume and water surface area of ​​a typical river section under normal conditions and during floods. A river section with a length that is n times the length of the unit river section is selected as a typical observation river section.

[0069] The deployment module is used to deploy remote sensing hydrological stations to collect remote sensing images of typical observation river sections, and the remote sensing images of the typical observation river sections are used to calculate the river flow of the typical observation river sections.

[0070] Compared with the prior art, the present disclosure has the following advantages:

[0071] The selection of equal-flux river sections based on DEM data and satellite-monitored rainfall data, whose stable hydrological characteristics help reduce uncertainty and provide a stable basis for subsequent operations;

[0072] Remote sensing data is used to extract water edges, and based on this, a digital grid model (DEM) is constructed to obtain precise terrain information. Accurate water edges and terrain information help select open and semi-open river sections with less interference and good visibility as typical river sections. These river sections have simpler flow conditions and more representative data, thus overcoming the problem that traditional hydrological stations cannot effectively cover large watersheds.

[0073] Open and semi-open river sections are selected as typical river sections from river sections with open sides or one side. The relationship curve between water surface area and reservoir capacity is constructed based on the river terrain information. The reasonable unit river section length is determined by combining the different state data of typical river sections. The typical observation river sections selected based on this can fully reflect the characteristics of the river channel, which helps to solve the problems of poor accuracy and monitoring effect of existing remote sensing hydrological stations.

[0074] The present invention can improve the overall remote sensing observation effect, realize the accurate identification and spatiotemporal dynamic monitoring of flood processes, and overcome the problems of insufficient temporal continuity and spatial coverage of traditional hydrological stations.

[0075] Other features and advantages of the present disclosure will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present disclosure. The purposes and other advantages of the present disclosure can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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.

[0077] Figure 1 A schematic diagram of the method of the present invention is shown. DETAILED DESCRIPTION

[0078] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0079] Traditional hydrological station monitoring can be summarized as "trading time for space." This involves long-term monitoring at fixed sites to obtain hydrological data such as flow and water level at a specific location over time. This approach describes the evolution of hydrological events through time series and is suitable for long-term hydrological observation and data accumulation. However, traditional hydrological stations are limited by their distribution and density, making it difficult to effectively cover large river basins. This is particularly limiting for monitoring data-starved rivers and remote mountainous areas.

[0080] Remote sensing hydrological stations employ a "space-for-time" approach, using remote sensing data to capture instantaneous water distribution and spatial characteristics through large-scale monitoring of fixed flow fields. The advantage of remote sensing hydrological stations lies in their wide-area coverage. Using multi-source remote sensing imagery, they can comprehensively and instantly capture hydrological characteristics at various locations within a watershed, thereby describing hydrological events in spatial terms.

[0081] This approach overcomes the problems of temporal continuity and insufficient spatial coverage in traditional methods, and is particularly suitable for dynamic flood monitoring of data-free rivers and large-scale water resource management.

[0082] Based on this, Figure 1 A schematic diagram of the method according to the present invention is shown, and specific implementation details of the present invention include:

[0083] Remote sensing hydrological station establishment process:

[0084] 1. Step 1: Select the isoflux river section

[0085] Specifically, they include:

[0086] 1.1) Data collection and preprocessing

[0087] Data collection: Use the 30m resolution Copernicus DEM to collect rainfall station data in the basin (or use satellite remote sensing rainfall products).

[0088] Watershed division: Based on DEM data, depression-filling processing is performed to generate a depression-free DEM, water flow direction data and cumulative runoff are calculated, watershed boundaries and river networks are extracted, and the watershed is divided into sub-basins according to the cumulative runoff, and the mainstream and tributaries of the runoff path are clarified.

[0089] 1.2) Calculation and analysis of cumulative flux intensity

[0090] 1.2.1) Based on the cumulative number of confluences (Method 1)

[0091] From upstream to downstream, the benchmark points are determined using the confluence accumulation grid map, the confluence accumulation numbers of each grid and the changing trends of the river section are counted, and the runoff flow on the confluence path is calculated using the confluence accumulation numbers.

[0092] Identify the location where the cumulative flux intensity changes by 5%, and classify the river section with a change within 5% as a stable flux river section. The confluence classification index is calculated based on the cumulative confluence number of the benchmark points of adjacent stable flux river sections for classification.

[0093] 1.2.2) Based on runoff accumulation and rainfall data (Method 2)

[0094] Interpolation methods such as the inverse distance weighted method are used to spread the point rainfall into a surface rainfall distribution map, and the rainfall per unit area of ​​each cell in the basin is calculated.

[0095] The cumulative flux intensity of the hydrological station is calculated based on the cumulative number of confluences, and then the stable flux river sections are identified and the confluence classification index is calculated in the same way as Method 1.

[0096] 1.3) Confluence classification and river section determination

[0097] According to the river flow monitoring specifications, the sections with flux errors within 5% are determined to be stable sections, and the rest are unstable sections.

[0098] 2. Step 2: Identify the topographic features of typical river sections and select river sections with open sides or one side based on remote sensing data.

[0099] Specifically, they include:

[0100] 2.1) Data Collection and Processing

[0101] Identify the river channel in the study area, specify the time range, and collect remote sensing image data from satellites such as Landsat series, Sentinel series, and Gaofen series at different times.

[0102] Perform radiometric correction, atmospheric correction, geometric correction and other operations on remote sensing image data to ensure image accuracy and consistency.

[0103] 2.2) Extract waterside and centerline

[0104] Extract river water morphology information from remote sensing image data and calculate water body normalization index using different bands Based on this index, multiple water edge lines and center lines at different times are extracted. Green and NIR are the remote sensing reflectances of the green band and near-infrared band, respectively.

[0105] 2.3) Determine the relevant waterside and center lines

[0106] The perpendicular line through the center line intersects with the water edge line, and the distance between the intersection points is calculated as the water surface width.

[0107] The average water surface width is calculated to obtain the average water surface width and determine the average water edge. The water surface widths are compared to determine the maximum water edge and the minimum water edge, and the center line corresponding to the minimum water edge is used as the basis for subsequent calculations.

[0108] 2.4) Calculate the moving distance ratio and identify the river section shape

[0109] The distance between the center line corresponding to the maximum water edge and the minimum water edge (first distance) and the distance between the center line corresponding to the average water edge and the minimum water edge (second distance) are calculated.

[0110] For the waterside lines on both sides of the river, the moving distance ratio value is calculated according to the formula (first distance - second distance) / second distance * 100%, and the threshold is set to 10%.

[0111] If the moving distance ratio of the waterside lines on both sides is <10%, the river section is a vertical river section; if the moving distance ratio of the waterside lines on one side is <10% and the other side is ≥10%, it is a unilateral vertical and unilateral open river section; if the moving distance ratio of the waterside lines on both sides is ≥10%, it is a bilateral open river section, thus selecting the river section with open sides or unilateral open.

[0112] The deployment of remote sensing hydrological stations enables remote sensing images to clearly observe the selected river sections that are open on both sides or one side, making it easier to conduct hydrological observations based on remote sensing images using remote sensing hydrological stations in the future.

[0113] 3. Step 3: Create river section terrain:

[0114] Specifically, the steps for constructing river section terrain based on water surface lines are as follows:

[0115] 3.1) Determine the waterside elevation;

[0116] For straight river sections: if the altimetry satellite measuring point coincides with the river section, take the elevation value at the intersection; if there is an angle, select the elevation value at the intersection of the altimetry satellite measuring point and the flow section, and assign it to the corresponding point on the waterside line.

[0117] For curved river sections: Due to the lateral gradient caused by centrifugal force, the elevation value at the water's edge is determined based on linear fitting of several existing points.

[0118] 3.2) Interpolation of elevation points and generation of a digital grid model: Extract multiple waterside lines and fuse them to generate an outer envelope line. Using this outer envelope line as the maximum interpolation range, interpolate the elevation values ​​on the waterside lines to obtain comprehensive and continuous elevation information.

[0119] Generate a digital grid model DEM of river terrain using elevation information

[0120] 4. Step 4: Roughly determine the typical river section:

[0121] Open and semi-open river sections are selected as typical river sections among river sections with stable runoff flow.

[0122] 5. Step 5: Determine the length of the unit river section:

[0123] The length of a typical river section is 5 unit river section lengths. Once the unit river section length is determined, the specific length of the typical river section can be confirmed.

[0124] The water volume of a typical river section under normal conditions is V0, and the water surface area of ​​the river section is A0. when When a flood comes, the water volume in a typical river section will rise. At this time, the water volume in the typical river section will increase to V1, and the water surface area of ​​the river section will also increase to A1.

[0125] Normal state: the amount of water in a unit river section is V 01 、V 02 、V 03 、V 04 、V 05 , the water surface area corresponding to a unit river section is A 01 、A 02 、A 03 、A 04 、A 05 ;

[0126] When a flood occurs: the amount of water in a unit river section is V 11 、V 12 、V 13 、V 14 、V 15 , the water surface area corresponding to a unit river section is A 11 、A 12 、A 13 、A 14 、A 15 ;

[0127] In the unit river section, when the flood occurs, the changed water volume is ΔV i , and the changed water surface area is ΔA i Then we have:

[0128] ΔV i = V 1i -V 0i

[0129] ΔA i = A 1i -A 0i

[0130] In the formula, i = 1, 2, 3, 4, 5.

[0131] Since the topography of the river section is known, the water volume in the unit river section and the water surface area of the unit river section have a certain correlation:

[0132] ΔV i = f(ΔA i )

[0133] The water surface area of the unit river section is related to the length of the unit river section. According to the correlation between the water volume in the river section and the water surface area of the river section, there is a unit river section length 1, so that:

[0134]

[0135] Take the length l at this time as the unit river section length.

[0136] Based on the unit river section length, a river section with a length of n times the unit river section length is selected as a typical observation river section in a typical river section. The length of the typical river section is greater than 5 times the unit river section length.

[0137] 6、Step 6: Use remote sensing images to carry out hydrological observation

[0138] Specifically, it includes:

[0139] 6.1) Estimation of river flow

[0140] Based on the selected typical river section, preferentially select a river section with open sides or a single open side for flow calculation to avoid setting measurement points in areas with steep or vertical sides on both sides. Take a 10-kilometer river section as a unit, and set a measurement point every 500 meters to measure the river section width. Calculate the river section flow through the multi-site hydraulic geometry relationship to realize the estimation of the river flow.

[0141] 6.2) River width extraction

[0142] Remote sensing images (such as Landsat and Sentinel-2) are used to extract the multi-temporal cross-sectional water surface width of typical river sections.

[0143] 6.3) Establish hydraulic geometry

[0144] This method sets the initial cross section at 500m intervals between river sections, obtains the spatiotemporal width changes of the river through remote sensing images, and calculates the flow rate based on the hydraulic geometric relationship between flow rate and water surface width.

[0145] w=aQ b

[0146] Where w is the water surface width, m; Q is the flow rate, m3 / s; a and b are hydraulic geometric parameters.

[0147]

[0148] Where x is the section number; w x is the average cross-sectional width, a x 、b x is the hydraulic geometric parameter of the x-th section; E is the specific parameter in the river channel;

[0149]

[0150] Where, is the water surface width of each section; p and y are fitting coefficients; x1, x2, ..., x n Subscripts correspond to cross-section locations within the reach.

[0151] The river width and flow were measured at multiple fixed sections in the same river section to establish a regression relationship between width and flow. The AMHG method was used to link the river width and flow at multiple stations through a log-linear relationship, where Approximate y to calculate specific hydraulic geometric parameters a and b.

[0152] 6.4) Traffic estimation and optimization:

[0153] Based on the range of hydraulic geometry parameters a and b and their log-linear relationship, the flow rate at any section can be calculated for a given pair of a and b values ​​and the river width. A genetic algorithm (GA) is used to solve the flow rate problem, optimizing it to minimize flow variance and ensure that the estimated results are within a reasonable range. Finally, the average of the multi-site flow rates is used as the flow estimate for the river section.

[0154] Table 1 GA parameter recommendation table

[0155]

[0156]

[0157] (1) For a pair of cross sections within a range, use GA to converge to a, b values inside to calculate the optimal flow (according to the classical hydraulic geometry relationship and the observed multi-time width calculation) Assuming the flow range is as follows:

[0158] Minimum allowable flow = observed minimum width x 0.5 m depth x 0.1 m / s velocity

[0159] Maximum allowable flow = observed maximum width x 10 m depth x 5 m / s velocity

[0160] (2) Repeat step 1 for 50 times to obtain 100 hydraulic geometry estimates for a pair of cross sections.

[0161] (3) Arrange steps 1 and 2 in geospatial, apply GA to all possible cross section pairs within the mass conservation range, which will produce (n 2 -n) x 100 GA-selected hydraulic geometry parameter estimates for each interface, where n is the number of cross sections within a 10 km range.

[0162] (4) Aggregate (n 2 -n) x 100 hydraulic geometry estimates to obtain the final hydraulic geometry for each interface in n cross sections. The GA output must be extracted from (n 2 -n) x 100 aggregate hydraulic geometry estimates provided by the spatial arrangement of individual hydraulic geometry for each cross section. The single-parameter nature of AMHG is utilized. The median value of a provided by GA is used in combination with the remote sensing AMHG approximation to calculate the corresponding b value for each cross section. Repeat this process using the median b value estimated by GA and AMHG to calculate a value, giving a, b values for each river section.

[0163] (5) Calculate flow Q according to the final selected hydraulic geometry parameters a, b. After determining the hydraulic geometry a and b, apply the resulting parameters to the cross-sectional water surface width obtained from remote sensing images to estimate the flow of each cross section in the relationship between flow and water surface width. This produces n flow estimates (one for each cross section), with the average flow as the estimated flow.

[0164] In summary: This patent proposes a remote sensing hydrological station layout method, aiming to use multi-source remote sensing data to dynamically monitor rivers and water bodies, especially for flood monitoring and early warning needs in ungauged rivers and remote mountainous areas.

[0165] This method combines the high spatial resolution advantage of remote sensing images with the dynamic modeling capability of traditional hydrological models, and through reasonable layout of remote sensing hydrological stations, realizes accurate identification and spatiotemporal dynamic monitoring of flood processes.

[0166] Based on the method of the present invention, the embodiment of the present disclosure further provides a system corresponding to the above method, which includes:

[0167] The selection module is used to select isoflux river sections based on DEM data and satellite-monitored rainfall data;

[0168] The river topography information acquisition module is used to extract the waterside lines of isoflux river sections based on remote sensing data, and select river sections with open sides or one side in the isoflux river sections; construct digital grid models (DEMs) of the river sections with open sides or one side based on the waterside lines, and use the digital grid models (DEMs) to obtain river topography information of the river sections;

[0169] Typical observation river section selection module, used to select open and semi-open river sections from river sections with open sides or open on one side as typical river sections;

[0170] Based on the river topography information, a curve of the relationship between water surface area and reservoir capacity is constructed. The length of a unit river section is determined by combining the water volume and water surface area of ​​a typical river section under normal conditions and during floods. A river section with a length that is n times the length of the unit river section is selected as a typical observation river section.

[0171] The deployment module is used to deploy remote sensing hydrological stations to collect remote sensing images of typical observation river sections, and the remote sensing images of the typical observation river sections are used to calculate the river flow of the typical observation river sections.

[0172] 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 cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for deploying remote sensing hydrological stations, characterized in that: include: Based on the DEM data, depression filling is performed to generate a depression-free DEM, calculate the water flow direction data and runoff accumulation, extract the watershed boundaries and river network, divide the watershed into levels based on the runoff accumulation number, and identify the main stream and tributaries of the runoff path; combine with rainfall data to obtain the runoff accumulation raster map; From upstream to downstream of the river section, the runoff flow on the confluence path is calculated using the cumulative confluence grid map to determine the benchmark points, and the cumulative confluence of each grid and the changing trend of the river section are counted. Identify the locations where the cumulative flux intensity changes by 5%, and define the river sections where the change is within 5% as equal flux sections; Based on remote sensing data, the waterfront of isoflux river sections is extracted, and river sections with open sides or one side are selected from these isoflux river sections. A digital grid model (DEM) of the river sections with open sides or one side is constructed based on the waterfront, and the DEM is used to obtain the river topography information of the river sections. Select open and semi-open river sections from river sections with open sides or open on one side as typical river sections; Based on the river topography information, a curve of the relationship between water surface area and reservoir capacity is constructed. The length of a unit river section is determined by combining the water volume and water surface area of ​​a typical river section under normal conditions and during floods. A river section with a length that is n times the length of the unit river section is selected as a typical observation river section. Deploying remote sensing hydrological stations to collect remote sensing images of typical observation river sections, wherein the remote sensing images of the typical observation river sections are used to calculate the river flow of the typical observation river sections; Determining the length of a unit river section includes: Find the length of the unit river section l such that Where ΔA i =A 1i -A 0i , A 1i A is the water surface area of ​​a unit river section when a flood occurs; 0i It is the water surface area of ​​a unit river section under normal conditions.

2. The method for deploying a remote sensing hydrological station according to claim 1, characterized in that: Calculate the river flow of a typical observed river section, including: Using remote sensing images of typical observed river sections, the multi-temporal water surface widths of multiple sections of the typical observed river sections are extracted; based on the multi-station hydraulic geometry of the typical observed river sections and the multi-temporal section water surface widths, the river flow is calculated.

3. The method for deploying a remote sensing hydrological station according to claim 2, characterized in that: The river flow is calculated based on the multi-station hydraulic geometry relationship of the typical observed river section and the water surface width of the multi-phase section; include: Initial cross sections are set at 500m intervals, and flow calculations are performed based on the hydraulic geometry relationship between flow and water surface width: w=aQ b Where, w is the width of the water surface, m; Q is the flow rate, m3 / s; a and b are hydraulic geometric parameters; Where x is the section number; w x is the average cross-sectional width, a x 、b x is the hydraulic geometric parameter of the x-th section; E is the specific parameter in the river channel; Where, is the water surface width of each section; p and y are fitting coefficients; Measurements were taken at multiple fixed sections within the same river reach to establish a regression relationship between water surface width and discharge. The AMHG method was used to link river width and discharge at multiple sites through a log-linear relationship. According to the value range of hydraulic geometric parameters a and b and the logarithmic linear relationship between a and b, the flow rate of any section can be calculated given a pair of a and b values ​​and the river width.

4. The method for deploying a remote sensing hydrological station according to claim 3, wherein: The values ​​of hydraulic geometric parameters a and b are obtained using genetic algorithms, which include: Given the initial value combination of hydraulic geometric parameters a and b; The river flow is calculated using the initial value combination of hydraulic geometric parameters a and b and relevant river data. The calculated value is compared with the actual observed flow to obtain the fitness value. Select the value combination of a and b with fitness higher than the threshold as the individual to enter the next generation population; Perform crossover operations based on the next generation population and mutation operations to obtain a new population; Iterate the new population to obtain the values ​​of hydraulic geometric parameters a and b.

5. The method for deploying a remote sensing hydrological station according to claim 1, characterized in that: The method of extracting the water edge of an isoflux river section based on remote sensing data includes: Extract river water morphology information from remote sensing image data; Calculate the normalized water index using different bands: Among them, Green and NIR are remote sensing reflectance of green band and near infrared band respectively; Based on the normalized water index, multiple water edges and center lines at different times are extracted; Draw a perpendicular line through the center line so that it intersects with the water's edge, and calculate the distance between the intersection points as the width of the water surface; Calculate the average water surface width to obtain the average water surface width and determine the average water edge; compare the water surface widths to determine the maximum water edge and the minimum water edge.

6. The method for deploying a remote sensing hydrological station according to claim 5, characterized in that: The step of selecting a river section with open sides or one side from a river section with equal flux includes: Calculating a first distance between the center line corresponding to the maximum water edge and the minimum water edge, and a second distance between the center line corresponding to the average water edge and the minimum water edge; For the waterside lines on both sides of the river, calculate the moving distance ratio according to the formula (first distance - second distance) / second distance * 100%; If the moving distance ratio of the water edges on both sides is <10%, the river section is a vertical section; if the moving distance ratio of the water edges on one side is <10% and the other side is ≥10%, it is a unilateral vertical and unilateral open section; if the moving distance ratio of the water edges on both sides is ≥10%, it is a bilateral open section, thus selecting the river section with open sides or unilateral open section.

7. The method for deploying a remote sensing hydrological station according to claim 1, characterized in that: The digital grid model DEM of the river section with open sides or one side based on the waterline is constructed, including: Determine the waterside elevation value; Extract multiple waterside lines and merge them to generate an outer envelope line. Interpolate the elevation values ​​on the waterside line within the maximum interpolation range based on the elevation value of the outer envelope line to obtain continuous elevation information. The digital grid model DEM of the river terrain is generated by using continuous elevation information. The river terrain includes underwater terrain, terrain from the maximum waterline to the minimum waterline, and terrain above the maximum waterline.

8. A method and system for deploying remote sensing hydrological stations, characterized in that: include: The selection module is used to generate a depression-free DEM by filling depressions based on DEM data, calculate water flow direction data and runoff accumulation, extract watershed boundaries and river networks, divide watersheds into different levels based on runoff accumulation, and identify the main streams and tributaries of the runoff path; and combine with rainfall data to generate a runoff accumulation grid map. From upstream to downstream of the river section, the runoff flow on the confluence path is calculated using the cumulative confluence grid map to determine the benchmark points, and the cumulative confluence of each grid and the changing trend of the river section are counted. Identify the locations where the cumulative flux intensity changes by 5%, and define the river sections where the change is within 5% as equal flux sections; The river topography information acquisition module is used to extract the waterside lines of isoflux river sections based on remote sensing data, and select river sections with open sides or one side in the isoflux river sections; construct digital grid models (DEMs) of the river sections with open sides or one side based on the waterside lines, and use the digital grid models (DEMs) to obtain river topography information of the river sections; Typical observation river section selection module, used to select open and semi-open river sections from river sections with open sides or open on one side as typical river sections; Based on the river topography information, a curve of the relationship between water surface area and reservoir capacity is constructed. The length of a unit river section is determined by combining the water volume and water surface area of ​​a typical river section under normal conditions and during floods. A river section with a length that is n times the length of the unit river section is selected as a typical observation river section. A deployment module is used to deploy remote sensing hydrological stations to collect remote sensing images of typical observation river sections, wherein the remote sensing images of the typical observation river sections are used to calculate the river flow of the typical observation river sections; Determining the length of a unit river section includes: Find the length of the unit river section l such that Where ΔA i =A 1i -A 0i , A 1i A is the water surface area of ​​a unit river section when a flood occurs; 0i It is the water surface area of ​​a unit river section under normal conditions.

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