A wind direction-based carbon sequestration service flow path characterization method

Abstract

The application discloses a carbon sequestration service flow path characterization method based on wind direction and belongs to the technical field of carbon sequestration services, and solves the problems that the existing carbon sequestration service flow is not visualized and the influence of wind direction is not considered. The application divides a research area into multiple spatial units, obtains the supply and demand of each unit, and determines the carbon sequestration service flow path in combination with annual dominant wind direction, so that the carbon sequestration service flow path can be more finely evaluated and characterized, the carbon sequestration service flow is visualized by using a network model and Gephi software, the spatial flow path of the carbon sequestration service is more intuitive, and the spatial flow law of the carbon sequestration service between the supply area and the demand area is directly revealed, so that managers and researchers can analyze and make decisions to realize reasonable matching of supply and demand.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon sequestration services, in particular to a carbon sequestration service flow path characterization method based on wind direction. BACKGROUND

[0002] Carbon sequestration service is an important regulating ecosystem service, which plays an important role in slowing the rise of atmospheric CO2 concentration and maintaining global carbon balance. It captures carbon in the atmosphere through the carbon sequestration function of the ecosystem and fixes the captured carbon, offsetting part of the CO2 emitted by humans into the atmosphere, thereby regulating the climate. Carbon sequestration service flow is the connecting process of carbon sequestration service from the supply area of the ecosystem to the demand area of human society, and is the description of the path of the service flow, which has the attributes of flow direction, flow speed and flow value.

[0003] For example, the patent with publication number CN118115174A provides a carbon sequestration service flow path simulation method, which includes data collection, including statistical data, vector data and raster data; the collected data is divided into natural ecological system carbon sequestration factors and human social carbon emissions, wherein the natural ecological carbon sequestration factor represents positive carbon sequestration service, and the human social carbon emission represents negative carbon sequestration service; the natural ecological carbon sequestration factor, the human social carbon emission and the result after the mutual action of the two are localized using the SPANs conceptual framework to obtain "source area", "sink area", "use area" and corresponding ecosystem service flow; the service flow is input into the BBN model for simulation, and finally the carbon sequestration service flow probability distribution is obtained.

[0004] Although this invention can obtain the carbon sequestration service flow probability distribution, it is not visualized, which is not convenient for understanding the path of carbon sequestration service flow, and the invention does not consider the influence of wind direction on carbon sequestration service. Wind direction indirectly or directly affects the carbon sequestration capacity of the ecosystem by affecting the gas exchange between plants and the atmosphere, regulating microclimate, changing soil erosion and improvement, affecting biodiversity and habitat composition, and affecting the efficiency of artificial carbon sequestration technology. Suitable wind direction and wind speed can promote the carbon capture efficiency and stability of the ecosystem, thereby enhancing carbon sequestration service; on the contrary, extreme wind direction or strong wind may cause soil erosion, limited plant growth, and even affect the operation of carbon capture technology, reducing the carbon sequestration effect. SUMMARY

[0005] In view of the above problems in the prior art, the present application provides a carbon sequestration service flow path characterization method based on wind direction, which solves the problem that the existing carbon sequestration service flow is not visualized and does not consider the influence of wind direction.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A wind direction-based carbon sequestration service flow path delineation method is provided, comprising the steps of:

[0008] S1, dividing the study area into multiple spatial units, using primary productivity NPP as the supply of carbon sequestration service of each unit, and calculating the demand of carbon sequestration service of each unit.

[0009] S2, calculating the supply and demand difference value of carbon sequestration service of each unit, DSDCS i = CS i - CD i , wherein DSDCS i , CS i and CD i are the supply and demand difference value, supply and demand of the i-th unit of carbon sequestration service respectively.

[0010] S3, using the center point tool of ArcGIS to extract the geographic coordinates of the center point of each unit as nodes, and taking the supply and demand difference value of carbon sequestration service of each unit as the weight of each node, if DSDCS i is greater than 0, the i-th node is a surplus node, otherwise it is a deficit node; the number of surplus nodes and loss nodes facilitates the analysis of the spatial matching state of supply and demand of carbon sequestration service.

[0011] S4, obtaining the annual dominant wind direction in each unit, determining the flow path between all nodes according to the annual dominant wind direction and taking it as the edge between nodes.

[0012] S5, constructing a carbon sequestration service flow network model according to all nodes and edges, and visualizing the carbon sequestration service flow network model by using Gephi.

[0013] In this scheme, considering that the supply and demand of carbon sequestration service often exist spatial mismatch within the study area scale, but it is difficult to intuitively understand the path of the study area, this scheme divides the study area into multiple spatial units, obtains the supply and demand of each unit, and determines the carbon sequestration service flow path combined with the annual dominant wind direction, which not only can more finely evaluate and delineate the carbon sequestration service flow path, but also can visualize the carbon sequestration service flow by using network model and Gephi software, making the spatial flow path of carbon sequestration service more intuitive, and intuitively revealing the spatial flow rule of carbon sequestration service between supply area and demand area, facilitating managers and researchers to analyze and make decisions to realize the reasonable matching of supply and demand.

[0014] Further, the calculation method of the demand of carbon sequestration service is:

[0015]

[0016] C pop = p x l x 365;

[0017] C agri = N f × EF f + N P × EF P + N m × EF m + N e × EF e + N a × EF a + N ir × EF ir ;

[0018]

[0019] C elec = N elec × EF elec ;

[0020] C heat = N heat × EF heat ;

[0021] where C pop , C agri , C anim , C elec and C heat are the carbon emissions of human respiration, agriculture, livestock, electricity and heat in the i-th unit, respectively; p and l are the number of people and the carbon dioxide emissions per person per day in the i-th unit, respectively; N f , N P , N m , N e , N a and N ir are the amount of chemical fertilizer, pesticide, agricultural plastic film, crop planting area, agricultural machinery power and irrigation area in the i-th unit, respectively; EF f , EF P , EF m , EF e , EF a and EF ir are the carbon emission factors of chemical fertilizer, pesticide, agricultural plastic film, crop, agricultural machinery and irrigation in the i-th unit, respectively; and are the CH4 emission factors of animal intestinal fermentation and manure management in the i-th unit, respectively, N i is the annual number of livestock and poultry of the i-th kind, N elec , N heat , EF elec and EF heatare the electricity consumption, total steam and hot water consumption, electricity emission coefficient, and emission factor in the i-th unit, respectively. By calculating the demand for carbon sequestration services in detail, taking into account carbon emissions from multiple sources, including residential respiration, agriculture, animal husbandry, electricity, and heat, the demand estimate is more comprehensive and accurate. This helps to more accurately assess the supply and demand gap for carbon sequestration services in each unit, thereby optimizing resource allocation.

[0022] Furthermore, Gephi's visualization of the carbon sequestration service flow network model includes determining whether each red-letter node can be satisfied by replenishment from a surplus node. If so, the edge between the red-letter node and the corresponding surplus node is a solid black line representing a flow edge; otherwise, it is a dashed red line representing a break edge. Visualizing the carbon sequestration service flow network model using Gephi can intuitively demonstrate whether each red-letter node can be satisfied by replenishment from a surplus node, helping to quickly identify key nodes and paths and improve decision-making efficiency.

[0023] Furthermore, cells corresponding to surplus nodes are ecological surplus areas, while cells corresponding to deficit nodes are ecological deficit areas. Clearly demarcating ecological surplus and deficit areas will help identify areas requiring key protection and areas requiring increased carbon sequestration services.

[0024] Furthermore, step S6 of evaluating the carbon sequestration service flow within the study area includes calculating the network density of the carbon sequestration service flow network model. The greater the network density, the better the overall connectivity of the carbon sequestration service flow network model.

[0025] Furthermore, the calculation method of the dominant wind direction per unit year is:

[0026]

[0027] Among them, d dom is the annual dominant wind direction of the unit, f(d j ) is the wind frequency distribution in the unit, n is the wind direction d j The number of times, m is the total number of wind direction measurements, d j is the jth wind direction in d, where d includes at least 16 wind directions. Determining the annual dominant wind direction through wind frequency distribution ensures data accuracy and reliability, helping to more accurately simulate the impact of wind direction on carbon sequestration service flow pathways.

[0028] Furthermore, wind direction d = [0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135°, 157.5°, 180°,

[0029] 202.5°, 225°, 247.5°, 270°, 292.5°, 315°, 337.5°]. Dividing the wind direction into 16 directions provides a more detailed wind direction classification, which helps to more accurately analyze the impact of wind direction on the carbon sequestration service flow path and improves the accuracy of the carbon sequestration service flow network model.

[0030] Furthermore, there is loss in the process of supplementary transfer of carbon sequestration service flow between the red node and the surplus node. The calculation method of the total loss factor in the carbon sequestration service flow path in the unit is:

[0031] R total =W d ×R t ×R v ×R b

[0032]

[0033] R v =exp(-k×NDVI)

[0034] R b =exp(-c×ρ)

[0035] Among them, R total is the total loss factor in the carbon sequestration service flow path in the unit, W d is the weight factor of the annual dominant wind direction, R t 、R v and R b are terrain resistance factor, vegetation resistance factor and building resistance factor respectively. is the average wind direction in unit d, d dom is the annual dominant wind direction in the cell, σ is the smoothing parameter, θ is the angle between the annual dominant wind direction and the slope in that direction, NDVI is the Normalized Difference Vegetation Index, k and c are constants representing the influence of vegetation and buildings on wind speed, respectively, and ρ is the building density in the annual dominant wind direction. By introducing terrain resistance factors, vegetation resistance factors, and building resistance factors, the impact of multiple factors on the carbon sequestration service flow path is comprehensively considered, making the loss calculation more comprehensive and accurate. This helps to more realistically simulate the actual transmission of carbon sequestration service flows.

[0036] The present invention discloses a method for depicting carbon sequestration service flow paths based on wind direction, which has the following beneficial effects:

[0037] 1. The present application can more accurately assess and depict the carbon sequestration service flow path by dividing the study area into multiple spatial units, obtaining the supply and demand of each unit, and determining the carbon sequestration service flow path in combination with the annual dominant wind direction. The present application can also visualize the carbon sequestration service flow using network models and Gephi software, making the spatial flow path of carbon sequestration service more intuitive, and directly revealing the spatial flow rules of carbon sequestration service between the supply area and the demand area, which facilitates managers and researchers to analyze and make decisions to achieve reasonable matching of supply and demand.

[0038] 2. The present application improves the accuracy of carbon sequestration service supply and demand matching. By collecting regional characteristic data, the present application can accurately calculate the carbon sequestration service supply and demand of each unit, and further determine the supply and demand difference of carbon sequestration service. Based on the scientific calculation of net primary productivity (NPP) and carbon emissions, the present application provides accurate data support for the matching of carbon sequestration service supply and demand.

[0039] 3. The present application enhances the visualization of carbon sequestration service flow path. By using Gephi software and geographic coordinate data extracted by ArcGIS, the present application constructs a carbon sequestration service flow network model, and realizes the intuitive display of spatial flow path between nodes through Geo layout. This visualization processing not only makes the path of carbon sequestration service flow clear and visible, but also represents the surplus or deficit state through nodes of different sizes and colors, further enhancing the intuitiveness and ease of understanding of information.

[0040] 4. The present application provides a theoretical basis and tool for regional carbon management. The network model of the present application provides a theoretical basis and visualization support for regional carbon management. By analyzing the relevant parameters of the carbon sequestration service flow network model, such as the number of surplus nodes and deficit nodes, the number of flow edges and interruption edges, and the network density, the overall state of regional carbon sequestration service flow can be evaluated, thereby providing scientific guidance for the formulation and implementation of carbon management measures.

[0041] 5. The present application simulates the dynamic changes of regional carbon sequestration service flow from the perspective of carbon sequestration service supply and demand, which plays an important role in the formation, transportation, transformation and maintenance of carbon sequestration service. The present application builds a bridge between carbon sequestration service supply and demand. The quantification and mapping of ecosystem service flow is the focus and difficulty of ecosystem service research. The present application visualizes the carbon sequestration service flow path based on wind direction, which is an attempt and exploration to a great extent, providing data and analysis support for local carbon management measures, and providing reference for regional carbon-related research. The present application has important significance for achieving the goal of low-carbon city and mitigating global warming. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Figure 1 is a schematic diagram of the composition of the carbon sequestration service flow network model;

[0043] Figure 2a visualized carbon sequestration service flow network model diagram; DETAILED DESCRIPTION

[0044] The specific embodiments of the present application are described below to facilitate the understanding of the present application for those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all the inventions utilizing the concept of the present application are within the scope of protection.

[0045] Embodiment 1

[0046] This embodiment takes a certain plateau city as a research area, and refers to Figure 1 , provides a carbon sequestration service flow path description method based on wind direction, comprising the steps of:

[0047] S1, divide a certain plateau city into multiple spatial units, use primary productivity NPP as the supply of carbon sequestration service of each unit, and calculate the demand of carbon sequestration service of each unit. NPP can not only reflect the productivity of vegetation community in natural environment, but also reflect the carbon fixation capacity of the earth's surface, therefore, the present application uses NPP to represent the supply of carbon sequestration service of a certain plateau city. In the embodiment, the NPP data is selected from the MODIS data (https: / / search.earthdata.nasa.gov / search / ) of the United States National Aeronautics and Space Administration (NASA), and the spatial resolution is 500m. The zoning statistics are carried out by using ArcGIS, and the carbon sequestration service supply reference table 1 of each prefecture-level city is obtained.

[0048] Table 1 Carbon sequestration service supply in 2019

[0049]

[0050]

[0051] The carbon sequestration service demand reference table 2 is shown in the following table.

[0052] Table 2 Carbon sequestration service demand in 2019

[0053]

[0054]

[0055] S2, calculate the carbon sequestration service supply and demand difference value DSDCS of each unit i = CS i - CD i , wherein DSDCS i , CS iand CD i respectively are the carbon fixation service supply-demand difference value, supply and demand of the i-th unit.

[0056] S3, the geographic coordinates of the center point of each unit are extracted as nodes by using the center point tool of ArcGIS, and the carbon fixation service supply-demand difference value of each unit is taken as the weight of each node. If the SDCS i is greater than 0, the i-th node is a surplus node, otherwise it is a deficit node; the number of surplus nodes and deficit nodes is conducive to analyzing the supply-demand space matching state of carbon fixation service. If the SDCS i is greater than 0, the i-th unit is an ecological surplus area, otherwise it is an ecological deficit area, that is, the unit corresponding to the surplus node is an ecological surplus area, and the unit corresponding to the deficit node is an ecological deficit area. Clearly dividing the ecological surplus area and the ecological deficit area helps to identify which areas need to be protected and which areas need to increase the supply of carbon fixation service.

[0057] In this embodiment, 37 nodes represent the surplus or deficit state of carbon fixation service, and the nodes are numbered according to 1-37.

[0058] S4, the annual dominant wind direction in each unit is obtained, and the flow path between all nodes is determined according to the annual dominant wind direction and taken as the edge between nodes.

[0059] S5, according to Figure 2 , a carbon fixation service flow network model is constructed according to all nodes and edges, and Gephi is used for visual processing of the carbon fixation service flow network model. The visual processing of the carbon fixation service flow network model by Gephi includes: judging whether each deficit node can be satisfied by the surplus node, if yes, the edge between the deficit node and the corresponding surplus node is a black solid line representing the flow edge, otherwise it is a red dotted line representing the interrupted edge.

[0060] In this embodiment, the 37 nodes are shown in Table 3.

[0061] Table 3

[0062]

[0063]

[0064] S6, according to the visual processing of the carbon fixation service flow network model, the carbon fixation service flow in the study area is evaluated, which includes calculating the network density of the carbon fixation service flow network model. The greater the network density, the better the overall connectivity of the carbon fixation service flow network model.

[0065] Table 4

[0066]

[0067] As shown in Table 4, there were 18 carbon surplus nodes, 19 deficit nodes, 29 flow edges and 11 interruption edges in a certain plateau area in 2019, and the network density of the service flow network was only 0.022. Compared with previous years, the carbon sequestration service shortage problem in a certain plateau area continued to worsen, and the connectivity of the service flow network remained at a low level.

[0068] Specifically, the calculation method of the demand amount of carbon sequestration service is as follows:

[0069]

[0070] In the formula, C pop , C agri , C anim , C elec and C heat are the carbon emissions of residents, agriculture, animal husbandry, electricity and heat in the i th unit, respectively.

[0071] In the formula, C pop = p x l x 365; p and l are the number of people and the carbon dioxide emission per person per day in the i th unit, respectively, and l = 0.75 kg.

[0072] C agri = N f × EF f + N P × EF P + N m × EF m + N e × EF e + N a × EF a + N ir × EF ir ; In the formula, N f , N P , N m , N e , N a and N ir are the use amounts of chemical fertilizers (kg), pesticides (kg), agricultural plastic film (kg), crop planting area (hm 2 ), agricultural machinery power (kW) and irrigation area (hm 2 ) in the i th unit, respectively; EF f , EF P , EF m , EF e , EF a and EF ir are the carbon emissions of chemical fertilizers, pesticides, agricultural plastic film, crop planting, agricultural machinery and irrigation, respectively.The carbon emission factors of fertilizer, pesticide, agricultural plastic film, crop, agricultural machinery and irrigation are 0.8956 kg / kg, 4.934 kg / kg, 5.180 kg / kg, 16.47 kg / hm, 0.1800 kg / kW and 20.476 kg / hm respectively. 2 2

[0073] are CH4 emission factors of animal intestinal fermentation and feces management, with the unit of kg / head / year. i is the annual feeding quantity of the i-th livestock and poultry, with the unit of head / year. 28 and 265 are global warming potential factors of CH4 and N2O in a time scale of one hundred years.

[0074] C elec = N elec × EF elec ; N elec and EF elec are the power consumption and power emission coefficient in the i-th unit respectively.

[0075] C heat = N heat × EF heat ; C heat is calculated from the total amount of steam and hot water N heat and the emission factor EF heat , and in this embodiment, the value of C heat is 0.11.

[0076] As a further scheme of this embodiment, the calculation method of the annual dominant wind direction is as follows:

[0077]

[0078] wherein d dom is the annual dominant wind direction of the unit, f(d j ) is the wind frequency distribution in the unit, n is the number of times of the wind direction d j , m is the total number of wind direction measurements, and d j is the j-th wind direction in the wind direction.

[0079] Wind direction d = [0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135°, 157.5°, 180°,

[0080] ​​​​​202.5°, 225°, 247.5°, 270°, 292.5°, 315°, 337.5°].

[0081] The wind direction is divided into 16 directions, which provides more detailed wind direction classification, helps to more accurately analyze the influence of wind direction on the carbon sequestration service flow path, and improves the accuracy of the carbon sequestration service flow network model.

[0082] As a further scheme of the embodiment, in order to make the loss calculation more comprehensive and accurate, and help to more realistically simulate the actual transmission of carbon sequestration service flow, considering various factors, in the judgment of whether each deficit node can be satisfied by the surplus node, a total loss factor of the carbon sequestration service flow path in the unit is introduced, and the calculation method is:

[0083] R total = W d × R t × R v × R b

[0084]

[0085] R v = exp(-k×NDVI)

[0086] R b = exp(-c×ρ)

[0087] Wherein, R total is the total loss factor of the carbon sequestration service flow path in the unit, W d is the weight factor of the annual dominant wind direction, R t , R v and R b are the terrain resistance factor, the vegetation resistance factor and the building resistance factor respectively, is the average wind direction of the unit in the wind direction d, d dom is the annual dominant wind direction in the unit, σ is the smoothing parameter, θ is the angle between the annual dominant wind direction and the aspect in the direction, NDVI is the normalized vegetation index, k and c are constants representing the influence degree of vegetation and buildings on wind speed respectively, and ρ is the building density in the annual dominant wind direction. By introducing the terrain resistance factor, the vegetation resistance factor and the building resistance factor, the influence of various factors on the carbon sequestration service flow path is considered comprehensively, so that the loss calculation is more comprehensive and accurate. This helps to more realistically simulate the actual transmission of carbon sequestration service flow.

[0088] In the embodiment, the total loss factor is used to more accurately judge whether each deficit node can be satisfied by the surplus node.

[0089] Although the specific embodiments of the application have been described in some detail, by way of example and for clarity of understanding, it should be understood that certain characteristics described herein can be used in various combinations and that other embodiments can be utilized without departing from the spirit of the patent as it is defined by the following claims.

Claims

1. A wind direction-based carbon sequestration service flow path profiling method, characterized in that, The method comprises the following steps: S1, dividing the research area into multiple spatial units, taking the primary productivity NPP as the supply of carbon fixation service of each unit, and calculating the demand of carbon fixation service of each unit; the calculation method of the demand of carbon fixation service is: ； ； ； ； ； ； in, 、 、 、 and Respectively Carbon emissions from residents’ breathing, agriculture, animal husbandry, electricity and heat in each unit; and Separate The number of people in each unit and the daily CO2 emissions per person; 、 、 、 、 and Respectively The amount of fertilizer used, pesticide used, agricultural plastic film used, crop planting area, agricultural machinery power and irrigation area in each unit; 、 、 、 、 and Respectively Carbon emission factors for fertilizers, pesticides, agricultural plastic films, crops, agricultural machinery, and irrigation in each unit; and Respectively CH4 emission factors for animal enteric fermentation and manure management in each unit, For the i The annual number of breeding livestock and poultry, 、 、 and Respectively Electricity consumption, total steam and hot water consumption, electricity emission coefficient and emission factor in each unit; S2, calculate the carbon sequestration service supply-demand difference value of each unit, wherein, , and are the carbon sequestration service supply-demand difference value, supply amount and demand amount of the first unit, respectively. S3, the geographic coordinates of the center point of each unit are extracted as nodes by using the center point tool of ArcGIS, and the carbon sequestration service supply-demand difference value of each unit is taken as the weight of each node. If the value is greater than 0, the first node is a surplus node, otherwise it is a deficit node. node is a surplus node, otherwise it is a deficit node;​ S4, obtaining the annual dominant wind direction in each unit, determining the flow path between all nodes according to the annual dominant wind direction and taking the annual dominant wind direction as the edge between the nodes; the calculation method of the unit annual dominant wind direction is: wherein, is the annual prevailing wind direction for the unit, is the wind frequency distribution in the unit, is the number of times the wind direction is m is the total number of measurements of the wind direction, is the number of times the wind direction is the first wind direction, comprises at least 16 wind directions; S5, constructing a carbon fixation service flow network model according to all nodes and edges, and visualizing the carbon fixation service flow network model by using Gephi.

2. The method of claim 1, wherein, The visualization processing of the carbon fixation service flow network model by Gephi includes: judging whether each deficit node can be satisfied by the surplus node, if yes, the edge between the deficit node and the corresponding surplus node is a black solid line representing the representative flow edge, otherwise it is a red dotted line representing the interrupted edge.

3. The method of claim 1, wherein, The unit corresponding to the surplus node is an ecological surplus area, and the unit corresponding to the deficit node is an ecological deficit area.

4. The method of claim 1, wherein, The evaluation of the carbon fixation service flow in the research area in step S6 includes calculating the network density of the carbon fixation service flow network model.

5. The method of claim 1, wherein, Wind direction 。 6. The method of claim 2, wherein, There is loss in the process of carbon fixation service flow supplement transmission between deficit nodes and surplus nodes, and the calculation method of the total loss factor in the carbon fixation service flow path in the unit is: = wherein, is the total loss factor in the carbon sequestration service flow path in the unit, is the weight factor of the annual prevailing wind direction, , and are the terrain resistance factor, the vegetation resistance factor and the building resistance factor, respectively, is the average wind direction in the unit , is the annual prevailing wind direction in the unit, is a smoothing parameter, is the angle between the annual prevailing wind direction and the aspect of the slope in the annual prevailing wind direction, is a smoothing parameter, is the normalized difference vegetation index, and are constants for the degree of influence of vegetation and buildings on wind speed, respectively, is the building density in the annual prevailing wind direction.

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