River micro-plastic spatial distribution simulation method and system

Abstract

The invention discloses a river micro-plastic spatial distribution simulation method and system. Comprising the following steps: firstly, determining a small watershed range covered by each tributary according to geographic space data of a monitoring area, and performing grid division on the small watershed range of each tributary to obtain a corresponding grid division layer; then, assigning each grid in the grid division layer according to the human activity data of the monitoring area, and determining the human activity data of each grid; and then, respectively carrying out statistical analysis on the human activity data of all grids in the small watershed range of each branch, determining an average value of the human activity data of the grids in the small watershed range of each branch, and calculating a micro-plastic abundance simulation value of each branch through a micro-plastic distribution simulation model according to the average value of the human activity data of the grids in the small watershed range of each branch. And finally, according to the micro-plastic abundance simulation values of all branches in the monitoring area, determining a micro-plastic spatial distribution result of the monitoring area by adopting a spatial interpolation algorithm. And large-range and low-cost rapid monitoring of micro-plastic distribution is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of data calculation methods applicable to specific applications, and particularly relates to a method and system for simulating the spatial distribution of river microplastics. Background Art

[0002] Wetland resources refer to ecosystems that cover specific areas on the earth's surface and are permanently or seasonally waterlogged, including natural or artificially formed areas such as swamps, lakes, rivers, tidal flats, and coastal wetlands. Wetlands are known as the "kidneys of the earth" because of their irreplaceable ecological functions in regulating climate, purifying water quality, and maintaining biodiversity. With the continuous development of social economy, the protection and threatened situation of wetland resources have received increasing attention, and microplastic pollution is an important aspect threatening wetland ecology. At present, the monitoring of wetland microplastics mainly relies on field sampling, and then microplastics are monitored in the laboratory through methods such as microscopic analysis, spectral analysis, and thermal analysis. The current wetland microplastic monitoring methods are time-consuming, costly in terms of manpower and funds, and it is difficult to meet the rapid monitoring of the spatial distribution of microplastics in large-scale wetlands. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, the present invention proposes a method and system for simulating the spatial distribution of river microplastics, which can quickly simulate the spatial distribution of microplastics in large-scale wetlands. The specific technical solutions are as follows:

[0004] In the first aspect, a method for simulating the spatial distribution of river microplastics is provided. In the first possible implementation manner of the first aspect, it includes:

[0005] Determine the small watershed range corresponding to each tributary within the monitoring area according to the geographical spatial data of the monitoring area, and perform grid division on each small watershed range;

[0006] Based on the human activity data of the monitoring area, assign values to each grid in each small watershed range to determine the human activity data corresponding to each grid;

[0007] Statistically analyze the human activity data corresponding to the grids in each small watershed range, and calculate the simulated microplastic abundance values of each tributary through a microplastic distribution simulation model according to the average value of the corresponding grid human activity data;

[0008] According to the simulated microplastic abundance values of all tributaries in the monitoring area, use a spatial interpolation algorithm to determine the simulated result of the spatial distribution of river microplastics in the monitoring area.

[0009] Combined with the first possible implementation manner of the first aspect, in the second possible implementation manner of the first aspect, the human activity data includes: population quantity, building vector data, and / or road vector data.

[0010] Combined with the first implementation manner of the first aspect, in the third implementation manner of the first aspect, the geospatial data includes: the digital elevation model of the monitoring area.

[0011] Combined with the first implementation manner of the first aspect, in the fourth implementation manner of the first aspect, determining the small watershed range corresponding to the tributary within the monitoring area includes:

[0012] Based on the geospatial data, using a hydrological analysis method to determine the small watershed range corresponding to the tributary within the monitoring area.

[0013] Combined with the first implementation manner of the first aspect, in the fifth implementation manner of the first aspect, the specific calculation formula of the microplastic distribution simulation model is as follows:

[0014] MP simulate = α×P + β×B + χ×R - c;

[0015] Wherein, P, B, and R are respectively the average value of the grid population quantity, the average value of the grid building area, and the average value of the grid road vector data of the small watershed range, α, β, and χ are respectively the coefficients corresponding to the average value of the grid population quantity, the average value of the grid building area, and the average value of the grid road vector data, and c is a constant.

[0016] Combined with the first implementation manner of the first aspect, in the sixth implementation manner of the first aspect, using a spatial interpolation algorithm to determine the simulation result of the spatial distribution of river microplastics in the monitoring area includes:

[0017] Assigning the calculated microplastic abundance simulation values to the estuaries of the corresponding tributaries respectively, and using the Kriging interpolation algorithm to determine the simulation result of the spatial distribution of river microplastics in the monitoring area.

[0018] Combined with the first implementation manner of the first aspect, in the seventh implementation manner of the first aspect, it further includes:

[0019] Based on the simulation result of the spatial distribution of river microplastics in the monitoring area, generating a corresponding simulation result map of the spatial distribution of river microplastics.

[0020] In the second aspect, a system for simulating the spatial distribution of river microplastics is provided. In the first implementation manner of the second aspect, it includes:

[0021] A grid division module, configured to determine the small watershed range corresponding to each tributary within the monitoring area according to the geospatial data of the monitoring area, and perform grid division on each small watershed range;

[0022] A grid assignment module, configured to assign values to each grid in the range of each small watershed based on the human activity data of the monitoring area, and determine the human activity data corresponding to each grid;

[0023] A simulation calculation module, configured to statistically analyze the human activity data corresponding to the grids in the range of each small watershed, and calculate the simulated microplastic abundance values of each tributary through a microplastic distribution simulation model according to the average value of the corresponding grid human activity data;

[0024] A spatial interpolation module, configured to determine the simulated spatial distribution result of river microplastics in the monitoring area by using a spatial interpolation algorithm according to the simulated microplastic abundance values of all tributaries in the monitoring area.

[0025] Combined with the first implementation manner of the second aspect, in the second implementation manner of the second aspect, it further includes:

[0026] A result mapping module, configured to generate a corresponding simulated spatial distribution result map of river microplastics based on the simulated spatial distribution result of river microplastics in the monitoring area.

[0027] Beneficial effects: By using the method and system for simulating the spatial distribution of river microplastics of the present invention, the spatial distribution of river microplastics in a large area can be quickly obtained, which has the advantages of high speed and high efficiency compared with the existing methods. Moreover, there is no need to carry out on-site sampling work, saving a large amount of labor costs and capital costs. The spatial distribution of historical microplastics in river wetlands can be simulated by collecting historical human activity data, which is beneficial to the analysis and comparison of monitoring results. And it has a relatively simple operation method and is easy to operate. Description of the Drawings

[0028] In order to more clearly illustrate the specific implementation manners of the present invention, the drawings required for use in the specific implementation manners will be briefly introduced below. In all the drawings, the components or parts do not necessarily draw according to the actual ratio.

[0029] Figure 1 It is a flowchart of the method for simulating the spatial distribution of river microplastics provided by an embodiment of the present invention;

[0030] Figure 2 It is a system block diagram of the system for simulating the spatial distribution of river microplastics provided by an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of the range of small watersheds of all tributaries on both sides of the river. Specific Embodiments

[0032] The embodiments of the technical solution of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0033] As Figure 1 shown in the flowchart of the method for simulating the spatial distribution of river microplastics, the simulation method includes:

[0034] Step 1: Determine the small watershed range corresponding to each tributary within the monitoring area according to the geospatial data of the monitoring area, and divide the small watershed ranges into grids;

[0035] Step 2: Assign values to each grid in the small watershed ranges based on the human activity data of the monitoring area to determine the human activity data corresponding to each grid;

[0036] Step 3: Statistically analyze the human activity data corresponding to the grids in the small watershed ranges, and calculate the simulated microplastic abundance values of each tributary through the microplastic distribution simulation model according to the average value of the corresponding grid human activity data;

[0037] Step 4: Determine the simulated result of the spatial distribution of river microplastics in the monitoring area by using the spatial interpolation algorithm according to the simulated microplastic abundance values of all tributaries in the monitoring area.

[0038] Specifically, first, the area range covered by each tributary within the wetland area can be determined according to the obtained geospatial data of the wetland area, that is, the small watershed range, and the small watershed range corresponding to each tributary can be divided into grids to obtain the corresponding grid division layer. Then, the human activity data of the wetland area can be used to assign values to each grid in the grid division layer to determine the human activity data corresponding to each grid. After that, the human activity data of all grids in the small watershed range covered by each tributary can be statistically analyzed respectively to determine the average value of the grid human activity data in the small watershed range of each tributary, and the simulated microplastic abundance value of each tributary can be calculated accordingly through the microplastic distribution simulation model. Finally, the spatial distribution result of microplastics within the wetland area can be determined by using the spatial interpolation algorithm according to the simulated microplastic abundance values of all tributaries in the wetland area.

[0039] In this way, without field sampling and methods such as microscopic analysis, spectral analysis, and thermal analysis, the monitoring of the spatial distribution of microplastics over a large area can be quickly realized. A large amount of labor costs and capital costs are saved. And the spatial distribution of historical microplastics in rivers and wetlands can be simulated by collecting historical human activity data, which is conducive to the analysis and comparison of monitoring results. And the operation method is relatively simple, with the advantage of being simple and easy to operate.

[0040] In this embodiment, optionally, the human activity data includes: population quantity, building vector data, and / or road vector data.

[0041] Human activities are the main sources of microplastics, and population quantity, building area, and road vector data are the main factors reflecting human activities. Through on-site analysis of the distribution and influencing factors of microplastics in multiple wetlands, it is found that microplastics generated by population, buildings, and roads will enter the water environment under the action of road surface runoff, municipal drainage, wind transportation, etc., and continuously flow into the main stream through tributaries. Therefore, in this embodiment, population quantity, building vector data, and road vector data are selected as parameters for simulating the spatial distribution of microplastics in wetland areas.

[0042] In this embodiment, optionally, the geospatial data includes: the digital elevation model of the monitoring area. Specifically, the small watershed range of tributaries within the monitoring area can be determined according to the elevation information in the digital elevation model or digital surface model of the monitoring area. Since the digital surface model not only contains elevation information but also other information, it is more complex to calculate the small watershed range of tributaries compared to the digital elevation model that directly records elevation information. Therefore, for the convenience of calculating the watershed range, this embodiment selects the digital elevation model to determine the small watershed range corresponding to tributaries within the monitoring area.

[0043] In this embodiment, optionally, determining the small watershed range corresponding to tributaries within the monitoring area includes: based on the geospatial data, using a hydrological analysis method to determine the small watershed range corresponding to tributaries within the monitoring area.

[0044] Specifically, on the basis of the digital elevation model of the wetland area, the hydrological analysis function in Arcgis10.8 software can be used to determine the small watershed range covered by each tributary in the wetland area. Specifically, first, the depression filling process can be performed on the digital elevation model of the wetland area to eliminate the depression points in the digital elevation model and avoid distortion of water flow simulation. Then, the eight-direction method can be used to determine the water flow direction of each grid in the digital elevation model, and the water flow accumulation amount flowing into each grid can be statistically calculated to reflect the surface runoff intensity. After that, according to the set flow threshold for screening, the grids with a flow rate greater than the flow threshold are selected to form a grid river network, and the grid river network is converted into vector line data to obtain a vector river network. Then, the pouring points where tributaries flow into the main stream are marked in the vector river network. Finally, taking the pouring points as the starting point for regional division, the small watershed range of each tributary can be determined according to the flow direction data. The specific results are as Figure 3 shown.

[0045] After determining the small watershed range corresponding to each tributary, the Createfishnet tool in Arcgis 10.8 software can be used to divide the small watershed range of each tributary into grids, and each divided grid is uniquely coded to obtain the corresponding grid division layer.

[0046] Then, based on the obtained population quantity data, the Zonal Statistics as Table tool in Arcgis 10.8 software is used to determine the population quantity of each grid in the grid division layer. And based on the obtained building vector data, the Spatial Join tool in Arcgis 10.8 software is used to determine the grid code corresponding to each building in the wetland area. And the Dissolve tool in Arcgis 10.8 software is used to perform polygon fusion according to the grid code, so as to determine the building area corresponding to each grid in the grid division layer. And based on the road vector data, the Internet tool in Arcgis 10.8 software is used to perform spatial overlay of the divided grid division layer and the obtained road vector data, and the Dissolve tool in Arcgis 10.8 software is used to perform polygon fusion according to the grid code, so as to calculate the road length within each grid range.

[0047] After assigning values to the human activity data of each grid in the wetland area, statistical analysis can be performed on the human activity data of the grids included in the small watershed range of each tributary, so as to determine the average value of the human activity data of the grids corresponding to each tributary.

[0048] Among them, the specific calculation formula for the average value of the grid population quantity is as follows:

[0049]

[0050] The specific calculation formula for the average value of the grid building area is as follows:

[0051]

[0052] The specific calculation formula for the average value of the grid road vector data is as follows:

[0053]

[0054] Among them, n is the total number of grids corresponding to the small watershed range, p i 、b i 、r i are the population quantity, building vector data, and road vector data corresponding to a single grid respectively.

[0055] In this embodiment, optionally, the specific calculation formula of the microplastic distribution simulation model is as follows:

[0056] MP simulate = α×P + β×B + χ×R - c;

[0057] Wherein, P, B, and R are respectively the average value of the grid population quantity, the average value of the grid building area, and the average value of the grid road vector data within the small watershed range; α, β, and χ are respectively the coefficients corresponding to the average value of the grid population quantity, the average value of the grid building area, and the average value of the grid road vector data, which can be set to 0.183, 0.002, and 0.032 respectively; c is a constant, which can be set to 19.948.

[0058] In this embodiment, optionally, a spatial interpolation algorithm is used to determine the simulation result of the spatial distribution of river microplastics in the monitoring area, including:

[0059] Assign the calculated simulated values of microplastic abundance to the estuaries of the corresponding tributaries respectively, and use the Kriging interpolation algorithm to determine the simulation result of the spatial distribution of river microplastics in the monitoring area.

[0060] Specifically, after calculating the simulated values of microplastic abundance corresponding to each tributary in the wetland area through the microplastic distribution simulation model, the corresponding simulated values of microplastic abundance can be assigned to the estuaries of each tributary. Then, based on the simulated values of microplastic abundance at the estuaries of each tributary, the Kriging interpolation algorithm is used to obtain the simulated values of microplastic abundance at other position points of the river, and the simulation result of the spatial distribution of river microplastics in the wetland area is obtained. The specific calculation formula of the Kriging algorithm is as follows:

[0061]

[0062] Wherein, m is the number of estuaries, Mnz j is the weight coefficient corresponding to the estuary, and Z(x j ) is the simulated value of microplastic abundance at the estuary of the tributary.

[0063] In this embodiment, optionally, it further includes:

[0064] Based on the simulation result of the spatial distribution of river microplastics in the monitoring area, a corresponding simulation result map of the spatial distribution of river microplastics is generated.

[0065] Specifically, after obtaining the simulation result of the spatial distribution of river microplastics in the entire wetland area, a corresponding simulation result map of the spatial distribution of river microplastics can be generated according to the simulation result of the spatial distribution of river microplastics, and the simulation result map of the spatial distribution of river microplastics is adjusted to an appropriate size, and at the same time, a scale, a north arrow, a legend, etc. are configured. Then, using the Exportmap tool, the image resolution is set to intuitively display the spatial distribution of river microplastics in the wetland area.

[0066] As Figure 2 shown in the system block diagram of the river microplastic spatial distribution simulation system, the simulation system includes:

[0067] A grid division module, configured to determine the small watershed range corresponding to each tributary within the monitoring area according to the geospatial data of the monitoring area, and perform grid division on each small watershed range;

[0068] A grid value assignment module, configured to assign values to each grid in each small watershed range based on the human activity data of the monitoring area, and determine the human activity data corresponding to each grid;

[0069] A simulation calculation module, configured to statistically analyze the human activity data corresponding to the grids in each small watershed range, and calculate the simulated microplastic abundance values of each tributary through a microplastic distribution simulation model according to the average value of the corresponding grid human activity data;

[0070] A spatial interpolation module, configured to determine the simulation result of the river microplastic spatial distribution within the monitoring area by using a spatial interpolation algorithm according to the simulated microplastic abundance values of all tributaries within the monitoring area.

[0071] Specifically, the simulation system includes a grid division module, a grid value assignment module, a simulation calculation module, and a spatial interpolation module. Among them, the grid division module can determine the area range covered by each tributary within the wetland area, that is, the small watershed range, according to the geospatial data of the obtained wetland area, and perform grid division on the small watershed range corresponding to each tributary to obtain the corresponding grid division layer. The grid value assignment module can assign values to each grid in the grid division layer according to the human activity data of the obtained wetland area to determine the human activity data corresponding to each grid. The simulation calculation module can respectively perform statistical analysis on the human activity data of all grids in the small watershed range covered by each tributary, determine the average value of the grid human activity data in the small watershed range of each tributary, and calculate the simulated microplastic abundance value of each tributary accordingly through the microplastic distribution simulation model. The spatial interpolation module can determine the microplastic spatial distribution result within the wetland area by using a spatial interpolation algorithm according to the simulated microplastic abundance values of all tributaries in the wetland area.

[0072] In this embodiment, optionally, it further includes:

[0073] A result mapping module, configured to generate a corresponding simulation result map of the river microplastic spatial distribution based on the simulation result of the river microplastic spatial distribution within the monitoring area.

[0074] Specifically, the simulation system further includes a result mapping module. The result mapping module can generate a corresponding simulation result map of the spatial distribution of river microplastics based on the spatial distribution result of microplastics obtained by the spatial interpolation module, adjust the simulation result map of the spatial distribution of river microplastics to an appropriate size, and at the same time configure a scale, a north arrow, a legend, etc. Then, using the Export map tool, set the image resolution to intuitively display the spatial distribution of river microplastics in the wetland area.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method for simulating the spatial distribution of microplastics in a river, characterized in that: include: Determine the small watershed range corresponding to each tributary within the monitoring area based on the geographic spatial data of the monitoring area, and divide each small watershed range into grids; Assigning a value to each grid in each small watershed based on the human activity data in the monitoring area to determine the human activity data corresponding to each grid; The human activity data corresponding to the grids in each small watershed are counted, and the simulated value of microplastic abundance in each tributary is calculated through the microplastic distribution simulation model based on the average value of the corresponding grid human activity data; According to the simulated values ​​of microplastic abundance in all tributaries within the monitoring area, a spatial interpolation algorithm is used to determine the simulated results of the spatial distribution of microplastics in rivers within the monitoring area.

2. The method for simulating the spatial distribution of river microplastics according to claim 1, characterized in that: The human activity data includes: population, building vector data and / or road vector data.

3. The method for simulating the spatial distribution of river microplastics according to claim 1, characterized in that: The geospatial data includes: a digital elevation model of the monitoring area.

4. The method for simulating the spatial distribution of river microplastics according to claim 1, characterized in that: Determine the small watershed range corresponding to the tributaries within the monitoring area, including: Based on the geospatial data, a hydrological analysis method is used to determine the scope of the small watershed corresponding to the tributaries within the monitoring area.

5. The method for simulating the spatial distribution of river microplastics according to claim 1, characterized in that: The specific calculation formula of the microplastic distribution simulation model is as follows: MP simulate =α×P+β×B+χ×Rc; Among them, P, B, and R are the average grid population, grid building area, and grid road vector data in the small watershed, respectively; α, β, and χ are the coefficients corresponding to the average grid population, grid building area, and grid road vector data, respectively; and c is a constant.

6. The method for simulating the spatial distribution of river microplastics according to claim 1, characterized in that: The spatial interpolation algorithm is used to determine the simulation results of the spatial distribution of river microplastics in the monitoring area, including: The calculated simulated values ​​of microplastic abundance are assigned to the river estuaries of the corresponding tributaries, and the Kriging interpolation algorithm is used to determine the simulated results of the spatial distribution of river microplastics in the monitoring area.

7. The method for simulating the spatial distribution of river microplastics according to claim 1, characterized in that: Also includes: Based on the simulation results of the spatial distribution of river microplastics in the monitoring area, a corresponding simulation result map of the spatial distribution of river microplastics is generated.

8. A system for simulating the spatial distribution of microplastics in rivers, characterized in that: include: A grid division module is configured to determine the small watershed range corresponding to each tributary within the monitoring area according to the geographic spatial data of the monitoring area, and to perform grid division on each small watershed range; A grid assignment module is configured to assign a value to each grid in each small watershed based on the human activity data in the monitoring area, and determine the human activity data corresponding to each grid; A simulation calculation module is configured to collect statistics on human activity data corresponding to the grids in each small watershed, and calculate the simulated value of microplastic abundance of each tributary through a microplastic distribution simulation model based on the average value of the corresponding grid human activity data; The spatial interpolation module is configured to determine the simulation results of the spatial distribution of microplastics in rivers within the monitoring area using a spatial interpolation algorithm based on the simulated values ​​of microplastic abundance in all tributaries within the monitoring area.

9. The river microplastic spatial distribution simulation system according to claim 8, characterized in that: Also includes: The result mapping module is configured to generate a corresponding river microplastic spatial distribution simulation result map based on the river microplastic spatial distribution simulation results within the monitoring area.

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