Drainage basin pollution reduction and carbon reduction coupling cooperation relation and drainage basin gravitational force evaluation method

Abstract

The invention relates to the technical field of drainage basin pollution reduction and carbon reduction, in particular to a drainage basin pollution reduction and carbon reduction coupling cooperative relation and drainage basin gravitational force evaluation method, which specifically comprises the following steps: collecting drainage basin pollutant and carbon emission data under a grid scale, collecting drainage basin'natural-economic-social 'factor data, and calculating annual pollutant and carbon reduction / increase emission; calculating the drainage basin pollution reduction and carbon reduction coupling degree and collaboration degree according to the pollutant and carbon reduction / increase discharge capacity, and obtaining a drainage basin pollution reduction and carbon reduction coupling collaboration relationship; the'nature-economy-society 'factor data of the watershed are analyzed, and a'nature-economy-society' comprehensive influence index is obtained; according to a gravity center method, obtaining drainage basin pollution reduction and carbon reduction gravity center coordinates and the distance between the drainage basins, and combining the coupling degree and the'nature-economy-society 'comprehensive influence index to obtain the pollution reduction and carbon reduction gravity intensity between the drainage basins. According to the method, the influence of natural, economic and social factors is fully considered, the drainage basin pollution reduction and carbon reduction coupling cooperation relationship and the gravitation intensity between the drainage basins can be accurately judged, and a scientific basis is provided for promoting cooperation between the drainage basins and establishing a cross-drainage-basin pollution reduction and carbon reduction cooperation mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of watershed pollution reduction and carbon reduction, and in particular to a method for evaluating the coupled synergistic relationship of watershed pollution reduction and carbon reduction and watershed gravity. Background Art

[0002] With the intensification of global climate change and ecological and environmental pressures, watershed pollution reduction and carbon reduction have become the focus of common concern of countries around the world. Since pollutants and greenhouse gases often originate from similar industrial activities or economic behaviors, the two show synergistic effects in some cases. However, in other situations, pollution reduction and carbon reduction may conflict. For example, certain pollutant control technologies may increase carbon emissions. Therefore, quantitative research on the coupled synergistic relationship between watershed pollution reduction and carbon reduction has become the key to ecological and environmental governance. At present, most of the coupled synergistic evaluation methods for watershed pollution reduction and carbon reduction focus on the overall status evaluation, and the dominant situation of pollution reduction or carbon reduction is still unclear, which makes it difficult to accurately formulate effective measures to achieve the dual goals of pollution reduction and carbon reduction in the actual watershed governance process.

[0003] Secondly, river basins are important units of water resources and ecosystems. Most river basins contain multiple cities, and the connections between nature, economy and society are more complex, resulting in complex interactions between river basins in terms of pollution reduction and carbon reduction. Studying the gravity of pollution reduction and carbon reduction between river basins can help scientists and decision makers better understand the collaborative governance mechanism between river basins and promote cross-regional environmental cooperation. However, the gravity intensity algorithm is currently only used to analyze the relationship between carbon emissions between cities, and its application at the river basin level is still in the initial exploration stage, and does not consider the impact of natural, economic and social factors on the system. This limitation makes it impossible to comprehensively and accurately describe and calculate the gravity of pollution reduction and carbon reduction between river basins through quantitative methods. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for evaluating the coupled synergy relationship of watershed pollution reduction and carbon reduction and watershed gravity.

[0005] The technical solution of the present invention to solve the above technical problems is:

[0006] A method for evaluating the coupled synergy relationship of watershed pollution reduction and carbon reduction and watershed gravity, comprising the following steps:

[0007] Step S1: Obtain multi-year time series data of pollutants and carbon emissions in the watershed at the grid scale; obtain time series data of the "natural-economic-social" factors of the watershed; accumulate the pollutant and carbon emission data in the grid of each watershed each year to obtain the total amount of pollutants and carbon emissions in each watershed in that year; calculate the annual reduction / increase of pollutants and carbon emissions based on the multi-year time series data of pollutants and carbon emissions;

[0008] Step S2: Standardize the annual pollutant and carbon emission reduction / increase data; use the coupling degree model to calculate the coupling degree between pollution reduction and carbon reduction in each river basin based on the standardized data set, and then obtain the pollution reduction and carbon reduction coupling degree level of each river basin;

[0009] Step S3: Based on the annual pollutant data and carbon emission reduction / increase data, the pollution reduction and carbon reduction synergy efficiency coefficient is used to calculate the synergy between pollution reduction and carbon reduction in each river basin; and then combined with the coupling degree between pollution reduction and carbon reduction in each river basin obtained in step S2, the pollution reduction and carbon reduction coupling synergy status of each river basin is quantitatively evaluated;

[0010] Step S4: Determine the centroid coordinates of pollutants and carbon emissions in each river basin according to the center coordinates of each grid and the pollutant and carbon emission data in each grid; connect the centroid coordinates of two river basins to obtain the straight-line distance between the centroids of the two river basins and standardize the straight-line distance data;

[0011] Step S5: construct the “natural-economic-social” comprehensive impact index of each basin based on the time series data of the “natural-economic-social” factors of the basin;

[0012] Step S6: Based on the coupling degree of each river basin, the comprehensive impact index of "nature-economy-society" and the straight-line distance between the centers of gravity, the gravitational intensity of pollution reduction and carbon reduction between river basins is calculated.

[0013] As a preferred solution of the present invention: in step S1, the time series data of the "natural-economic-social" factors of the watershed include: natural: main stream flow of the watershed, average annual precipitation, vegetation coverage, number of species in the watershed; economic: GDP of the watershed, average utilization rate of watershed resources, export trade volume of the watershed, and flow of ecological compensation funds; social: population flow, watershed logistics volume, mileage of watershed roads, and urbanization rate. For natural factors, the flow of the main stream of the basin and the average annual precipitation reflect the circulation intensity of pollutants and carbon between basins with water as the medium, the vegetation coverage reflects the carbon storage capacity between basins, and the number of species in the basin reflects the degree of negative impact of pollutants and carbon on the basin; for economic factors, the GDP of the basin and the average utilization rate of basin resources reflect the emission intensity of pollutants and carbon in the basin, the export trade volume of the basin reflects the circulation intensity of pollutants and carbon between basins with economic exchange as the medium, and the flow of ecological compensation funds reflects the intensity of ecological governance in the basin; for social factors, population mobility, basin logistics volume, and basin road mileage reflect the circulation intensity of pollutants and carbon between basins with people and objects as the medium, and the urbanization rate reflects the emission intensity of pollutants and carbon in the basin.

[0014] As a preferred solution of the present invention: in step S1, the total amount of pollutants and the total amount of carbon emissions are calculated as follows:

[0015]

[0016]

[0017] Among them, POL i is the total amount of pollutant emissions in year i; POL ij is the emission of pollutants in the jth grid in the i-th year; CAR i is the total carbon emissions in year i; CAR ij is the carbon emission in the jth grid in year i; n is the total number of grids in each basin.

[0018] As a preferred solution of the present invention: in step S1, the annual reduction / increase of pollutants and carbon emissions is calculated, and the specific calculation formula is:

[0019] ΔPOL i =POL i-1 -POL i ;

[0020] ΔCAR i =CAR i-1 -CAR i ;

[0021] Where, ΔPOL i is the difference in pollutant emissions between year i and year (i-1), where ΔPOL i >0 means pollutant emission reduction, ΔPOL i <0 means pollutant emission increase; POL i-1 is the total amount of pollutant emissions in year (i-1); POL i is the total amount of pollutant emissions in year i; ΔCAR i is the difference in carbon emissions between year i and year (i-1), where ΔCAR i >0 means carbon reduction, ΔCAR i <0 means carbon emission increase; CAR i-1 is the total carbon emissions in year (i-1), CAR i is the total carbon emissions in year i.

[0022] As a preferred solution of the present invention: in step S2, the specific formula for standardizing the pollutant and carbon emission reduction / increase data is as follows:

[0023]

[0024]

[0025] Among them, U is the standardized reduction / increase of pollutant emissions, ΔPOL iis the reduction / increase of pollutant emissions before standardization, B is the reduction / increase of carbon emissions after standardization, ΔCAR i is the reduction / increase of carbon emissions before normalization, and k is the total number of pollutant data.

[0026] As a preferred solution of the present invention: in step S2, the coupling degree model is:

[0027]

[0028] Among them, C i is the coupling degree of pollution reduction and carbon reduction in the i-th year, and its value range is [0,1]; C i The closer it is to 1, the higher the coupling degree; U i is the difference of pollutant emissions in the i-th year after standardization; B i is the standardized carbon emission difference in year i.

[0029] As a preferred solution of the present invention: in step S3, the synergy efficiency coefficient of pollution reduction and carbon reduction is used to calculate the synergy between pollution reduction and carbon reduction in each river basin. The specific formula is as follows:

[0030]

[0031] Among them, S i is the coordination degree of pollution reduction and carbon reduction in the i-th year; ΔPOL i POL is the difference in pollutant emissions between year i and year (i-1); i is the total amount of pollutant emissions in year i; ΔCAR i is the difference in carbon emissions between year i and year (i-1); CAR i is the total carbon emissions in year i;

[0032] S i The value range is (-∞,+∞), when S i When <0, it means that pollution reduction and carbon reduction are not coordinated; when 0≤S i When <0.8, it indicates synergy dominated by carbon reduction; when 0.8≤S i When S is ≤1.2, it indicates the synergy of pollution reduction and carbon reduction. i When it is >1.2, it indicates coordination dominated by pollution reduction.

[0033] As a preferred solution of the present invention: in step S4, the centroid method is used to determine the centroid of pollutants and carbon emissions in each river basin, and the specific formula is as follows:

[0034]

[0035]

[0036] Among them, X i , Y i are the horizontal and vertical coordinates of the center of gravity of pollutants and carbon emissions in the basin in year i, respectively; j ,y j is the horizontal and vertical coordinates of the jth grid cell; POL ij is the emission of pollutants in the jth grid in the i-th year; CAR ij is the carbon emission in the jth grid in year i; n is the total number of grids in each basin.

[0037] As a preferred solution of the present invention: in step S5, the improved CRITIC method is used to calculate the "nature-economy-society" comprehensive impact index. The improved CRITIC method can fully consider the variability and conflict between the 12 "nature-economy-society" factors selected in step S1, so that the weighting of each factor is more scientific, and then the "nature-economy-society" comprehensive impact index is calculated. The specific steps are:

[0038] Step S501: construct an initial factor matrix:

[0039]

[0040] Step S502: Standardize the “nature-economy-society” factor data to obtain a standardized matrix:

[0041]

[0042] Among them, for a certain river basin, a ij , a′ ij are the jth “natural-economic-social” factor in the i-th year before and after standardization, respectively;

[0043] Step S503: Calculate the variability of each factor based on the standardized "nature-economy-society" factor. Variability refers to the volatility of the same factor under time changes. The larger the value, the stronger the volatility of the factor over time, so the greater the weight assigned. The specific formula is as follows:

[0044]

[0045] Among them, E j is the variation index of the jth “nature-economy-society” factor; a′ ij is the jth “nature-economy-society” factor in the i-th year after standardization; is the average value of the jth factor; m is the number of factors;

[0046] Step S504: Pearson correlation coefficient method is used to calculate the correlation between the “nature-economy-society” factors, and then the conflict between the factors is calculated. The conflict between the factors refers to the degree of association between different factors. The greater the conflict between two factors, the weaker the association between the two factors, and the more different points of information reflected, so the greater the weight assigned. The specific formula is as follows:

[0047]

[0048] Among them, R j is the conflict index of the jth “nature-economy-society” factor; |r qj | is the absolute value of the Pearson correlation coefficient between the qth factor and the jth factor; m is the number of factors;

[0049] Step S505: Calculate the weight of each factor according to the variation index and conflict index of each "nature-economy-society" factor. The specific formula is as follows:

[0050]

[0051] Among them, W j is the weight of the jth “nature-economy-society” factor; E j is the variation index of the jth “nature-economy-society” factor; R j is the conflict index of the jth “nature-economy-society” factor; m is the number of factors;

[0052] Step S506: Calculate the “Nature-Economy-Society” comprehensive impact index according to the weights of each “Nature-Economy-Society” factor. The specific formula is as follows:

[0053]

[0054] Among them, V z is the comprehensive impact index of “nature-economy-society” of the zth basin; W j is the weight of the jth “nature-economy-society” factor; a′ ij is the jth “natural-economic-social” factor in the i-th year after standardization; m is the number of factors.

[0055] As a preferred solution of the present invention: in step S6, the calculation formula of the gravitational strength is:

[0056]

[0057]

[0058] Among them, G ijis the gravitational strength of basin i on basin j. The larger the value, the stronger the relationship, influence and coupling effect between basins in reducing pollution and carbon emissions. ij is the gravity coefficient of basin i to basin j; C i , C j are the coupling degrees of basin i and basin j respectively; V i 、V j D is the comprehensive impact index of “nature-economy-society” of basin i and basin j; ij is the straight-line distance from the centroid of the watershed.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] 1. The method for evaluating the coupled synergistic relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed of the present invention collects and analyzes pollutant and carbon emission data in the watershed, and calculates the coupling degree and synergy of pollution reduction and carbon reduction in the watershed using a coupling degree model and a synergy efficiency coefficient. It can clearly evaluate the coupling relationship of pollution reduction and carbon reduction between watersheds and accurately determine the synergistic dominant relationship.

[0061] 2. The method for evaluating the coupled synergistic relationship of pollution reduction and carbon reduction in river basins and the gravity of river basins of the present invention adopts the coupling degree of pollution reduction and carbon reduction, and analyzes and calculates the gravitational intensity of pollution reduction and carbon reduction between river basins while fully considering the influence of nature, economy and society. It can help understand the gravitational radiation relationship of pollution reduction and carbon reduction between river basins, and is conducive to timely adjusting pollution reduction and carbon reduction policies according to the gravitational relationship, promoting coordinated cooperation between river basins, establishing a cross-basin pollution reduction and carbon reduction cooperation mechanism, improving the overall effect of pollution reduction and carbon reduction, and providing a more scientific decision-making basis for sustainable development and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a flow chart of the coupled synergistic relationship for watershed pollution reduction and carbon reduction and the watershed gravity evaluation method of the present invention.

[0063] Figure 2 Schematic diagram of the grid coordinate locations in Basin 1 and Basin 2.

[0064] Figure 3 This is a table of pollutant emissions and carbon emissions parameters for each grid in Basin 1 and Basin 2 from 2019 to 2023.

[0065] Figure 4 This is a time series data table of the “Nature-Economy-Society” factors for each grid in Basin 1 and Basin 2 from 2019 to 2023.

[0066] Figure 5 Schematic diagram of the centroid and straight-line distance connection in Basin 1 and Basin 2.

[0067] Figure 6It is the calculation result of the variation index of each "natural-economic-social" factor in the basin.

[0068] Figure 7 is the Pearson correlation coefficient between the “natural-economic-social” factors in the basin.

[0069] Figure 8 It is the calculation result of the conflict index of each “natural-economic-social” factor in the basin.

[0070] Fig. 9 It is the calculation result of the weights of each “natural-economic-social” factor in the basin.

[0071] Fig.10 It is the calculation result of the comprehensive impact index of “nature-economy-society” of each river basin. DETAILED DESCRIPTION

[0072] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0073] Please refer to Figure 1 The method for evaluating the coupled synergy relationship of watershed pollution reduction and carbon reduction and watershed gravity of the present invention comprises the following steps:

[0074] Step S1: Obtain multi-year time series data of pollutants and carbon emissions in the watershed at the grid scale; obtain the time series data of the "natural-economic-social" factors of the watershed; accumulate the pollutant and carbon emission data in the grid of each watershed each year, and obtain the total amount of pollutants and carbon emissions in each watershed in that year; calculate the annual reduction (increase) of pollutants and carbon emissions based on the multi-year time series data of pollutants and carbon emissions;

[0075] In this embodiment, the time series data of the "natural-economic-social" factors of the river basin include: natural: river basin mainstream flow, average annual precipitation, vegetation coverage, and number of species in the river basin; economic: river basin GDP, average utilization rate of river basin resources, river basin export trade volume, and ecological compensation fund flow; social: population mobility, river basin logistics volume, river basin road mileage, and urbanization rate. For natural factors, the flow of the main stream of the basin and the average annual precipitation reflect the circulation intensity of pollutants and carbon between basins with water as the medium, the vegetation coverage reflects the carbon storage capacity between basins, and the number of species in the basin reflects the degree of negative impact of pollutants and carbon on the basin; for economic factors, the GDP of the basin and the average utilization rate of basin resources reflect the emission intensity of pollutants and carbon in the basin, the export trade volume of the basin reflects the circulation intensity of pollutants and carbon between basins with economic exchange as the medium, and the flow of ecological compensation funds reflects the intensity of ecological governance in the basin; for social factors, population mobility, basin logistics volume, and basin road mileage reflect the circulation intensity of pollutants and carbon between basins with people and objects as the medium, and the urbanization rate reflects the emission intensity of pollutants and carbon in the basin.

[0076] The specific formulas used for the accumulation of pollutants and total carbon emissions are as follows:

[0077]

[0078]

[0079] Among them, POL i is the total amount of pollutant emissions in year i; POL ij is the emission of pollutants in the jth grid in the i-th year; CAR i is the total carbon emissions in year i; CAR ij is the carbon emission in the jth grid in year i; n is the total number of grids in each basin;

[0080] The specific formulas used to calculate the annual reduction (increase) of pollutants and carbon emissions are as follows:

[0081] ΔPOL i =POL i-1 -POL i ;

[0082] ΔCAR i =CAR i-1 -CAR i ;

[0083] Where, ΔPOL i ΔPOL is the difference in pollutant emissions between year i and year (i-1); i >0 means pollutant emission reduction, ΔPOL i <0 means pollutant emission increase; POL i-1 is the total amount of pollutant emissions in year (i-1); POL i is the total amount of pollutant emissions in year i; ΔCAR i ΔCAR is the difference in carbon emissions between year i and year (i-1), i >0 means carbon reduction, ΔCAR i <0 means carbon emission increase; CAR i-1 is the total carbon emissions in year (i-1); CAR i is the total carbon emissions in year i.

[0084] Assume that both Basin 1 and Basin 2 contain 6 grids (the grid distribution and the location of each grid coordinate point are as follows: Figure 2 ), the parameters (unit, t) composition of each grid from 2019 to 2023 and the parameters of the “nature-economy-society” factor are as follows Figure 3 and Figure 4 As shown in the figure, the total emissions of pollutants and carbon in the two basins are calculated by the accumulation method:

[0085] Total emissions of pollutants and carbon in Basin 1 (t):

[0086] POL 2019 =63+59+59+56+57+65=359 (the same applies to the others, the calculation method is omitted);

[0087] POL 2020 =308;POL 2021 =234;POL 2022 =227;POL 2023 =180;

[0088] CAR 2019 =358; CAR 2020 =299; CAR 2021 =237; CAR 2022 =225; CAR 2023 =181;

[0089] Total emissions of pollutants and carbon in Basin 2 (t):

[0090] POL 2019 =841;POL 2020 =779;POL 2021 =725;POL 2022 =702;POL 2023 =673;

[0091] CAR 2019 =505; CAR 2020 =437; CAR 2021 =386; CAR 2022 =702; CAR 2023 =673;

[0092] Based on the cumulative results of pollutant and carbon emissions in Basin 1 and Basin 2, the difference in pollutant and carbon emissions between the two basins from 2019 to 2023 is calculated. Since data before 2019 are not assumed, the difference is calculated starting from 2020:

[0093] Difference in pollutant and carbon emissions in Basin 1 (t):

[0094] ΔPOL 2020 =359-308=51 (the same applies to the others, the calculation method is omitted);

[0095] ΔPOL 2021 =74; ΔPOL 2022 =7; ΔPOL 2023 =47;

[0096] ΔCAR 2020 =59; ΔCAR 2021 =62; ΔCAR 2022 =12; ΔCAR 2023 =44;

[0097] Difference in pollutant and carbon emissions in Basin 2 (t):

[0098] ΔPOL 2020 =62; ΔPOL 2021 =54; ΔPOL 2022 =23; ΔPOL 2023 =29;

[0099] ΔCAR 2020 =68; ΔCAR 2021 =51;ΔCAR 2022 =65; ΔCAR 2023 =52.

[0100] Step S2: Standardize the annual pollutant and carbon emission reduction (increase) data; use the coupling degree model to calculate the coupling degree between pollution reduction and carbon reduction in each river basin based on the standardized data set, and then obtain the pollution reduction and carbon reduction coupling degree level of each river basin;

[0101] The specific formula used in the present invention to standardize the pollutant and carbon reduction (increase) emission data is as follows:

[0102]

[0103]

[0104] Among them, U is the reduction (increase) of pollutant emissions after standardization; ΔPOL i is the reduction (increase) of pollutant emissions before standardization; B is the reduction (increase) of carbon emissions after standardization; ΔCAR i is the reduction (increase) of carbon emissions before standardization; k is the total number of pollutant data;

[0105] The coupling degree model used is used to calculate the coupling degree between pollution reduction and carbon reduction in each river basin. The specific formula is as follows:

[0106]

[0107] Among them, C i is the coupling degree of pollution reduction and carbon reduction in the i-th year, with a value range of [0,1], C i The closer it is to 1, the higher the coupling degree; i is the difference of pollutant emissions in the i-th year after standardization; B i is the carbon emission difference in the i-th year after standardization.

[0108] By standardizing the difference between pollutant and carbon emissions in each basin calculated in step S1:

[0109] Normalized discharge difference for Basin 1:

[0110]

[0111] U 2021 =0.545; U 2021 =0.052; U 2021 =0.346;

[0112] B 2020 =0.384; B 2020 =0.404; B 2020 =0.078; B 2020 =0.287;

[0113] Normalized discharge difference for Basin 2:

[0114] U 2020 =0.456; U 2021 =0.397; U 2021 =0.169; U 2021 =0.213;

[0115] B 2020 =0.443; B 2020 =0.332; B 2020 =0.423; B 2020 =0.339;

[0116] The coupling model used then calculates the coupling between pollution reduction and carbon reduction in Basin 1 and Basin 2 from 2020 to 2023:

[0117] The coupling degree of pollution reduction and carbon reduction in Basin 1 each year:

[0118]

[0119] C 2021 =0.989; C 2022 =0.979; C 2023 =0.996;

[0120] The coupling degree of pollution reduction and carbon reduction in Basin 2 each year:

[0121] C 2020 =1.000; C 2021 =0.996; C 2022 =0.903; C 2023 =0.974.

[0122] According to the calculation results of the coupling degree of pollution reduction and carbon reduction in each river basin, the coupling degree level of pollution reduction and carbon reduction in each river basin can be analyzed. The coupling degree value range is [0,1]. The closer to 1, the higher the coupling degree of pollution reduction and carbon reduction in the river basin, and the stronger the correlation between pollution reduction and carbon reduction. For example, in this embodiment, the coupling degrees of river basin 1 in the four years are 1.000, 0.989, 0.979 and 0.996 respectively, and the coupling degrees of river basin 2 in the four years are 1.000, 0.996, 0.903 and 0.974 respectively.

[0123] Step S3: Based on the annual pollutant and carbon emission reduction (increase) data, the synergy between pollution reduction and carbon reduction in each river basin is calculated using the pollution reduction and carbon reduction synergy efficiency coefficient; and then combined with the coupling degree between pollution reduction and carbon reduction in each river basin in step S2, the pollution reduction and carbon reduction coupling synergy state of each river basin is quantitatively evaluated;

[0124] The present invention uses the pollution reduction and carbon reduction synergy efficiency coefficient to calculate the synergy between pollution reduction and carbon reduction in each river basin. The specific formula is as follows:

[0125]

[0126] Among them, S i is the coordination degree of pollution reduction and carbon reduction in the i-th year; ΔPOL i POL is the difference in pollutant emissions between year i and year (i-1); i is the total amount of pollutant emissions in year i; ΔCAR i is the difference in carbon emissions between year i and year (i-1); CAR i is the total carbon emissions in year i;

[0127] S i The value range is (-∞,+∞), when S i When <0, it means that pollution reduction and carbon reduction are not coordinated; when 0≤S i When <0.8, it indicates synergy dominated by carbon reduction; when 0.8≤S i When S is ≤1.2, it indicates the synergy of pollution reduction and carbon reduction. i When it is >1.2, it indicates coordination dominated by pollution reduction.

[0128] Then, combined with the coupling degree of pollution reduction and carbon reduction in each river basin in step S2, the coupling synergy state of pollution reduction and carbon reduction in each river basin is quantitatively evaluated. The coupling synergy state corresponding to the coupling degree and synergy value range is shown in Table 1:

[0129] Table 1: Coupling coordination status table

[0130]

[0131]

[0132] The synergy efficiency coefficient of pollution reduction and carbon reduction is used to calculate the synergy between pollution reduction and carbon reduction in Basin 1 and Basin 2 from 2020 to 2023:

[0133] The coordination degree of pollution reduction and carbon reduction in Basin 1 each year:

[0134]

[0135] S 2021 =1.209; S 2022 =0.578; S 2023 =1.074;

[0136] The coordination degree of pollution reduction and carbon reduction in Basin 2 each year:

[0137] S 2020 =0.511; S 2021 =0.564; S 2022 =0.162; S 2023 =0.223;

[0138] Combined with the coupling degree of pollution reduction and carbon reduction between Basin 1 and Basin 2 calculated in step S2, and compared with the coupling synergy state table (i.e., Table 1), the coupling synergy state of pollution reduction and carbon reduction between Basin 1 and Basin 2 from 2020 to 2023 is determined; that is:

[0139] The coupling synergy status of Basin 1 during the four years were: high coupling and coordinated emission reduction driven by pollution reduction and carbon reduction, high coupling and coordinated emission reduction dominated by pollution reduction, high coupling and coordinated emission reduction dominated by carbon reduction, and high coupling and coordinated emission reduction driven by pollution reduction and carbon reduction;

[0140] The coupling synergy status of Basin 2 during the four years was: high coupling and carbon reduction-dominated synergistic emission reduction.

[0141] Step S4: According to the center coordinates of each grid (the center coordinates of the grid with irregular boundaries are determined by the center of the largest inscribed circle) and the pollutant and carbon emission data in each grid, the center of gravity of pollutants and carbon emissions in each river basin is determined using the center of gravity method; the center of gravity coordinates of the two river basins are connected to obtain the straight-line distance between the centers of gravity of the two river basins and standardize the straight-line distance data.

[0142] The present invention adopts the centroid method to determine the centroid of pollutants and carbon emissions in each river basin. The specific formula is as follows:

[0143]

[0144]

[0145] Among them, X i , Y i are the horizontal and vertical coordinates of the pollutant and carbon emission centers of the basin in year i;j ,y j is the horizontal and vertical coordinates of the jth grid cell; POL ij is the emission of pollutants in the jth grid in the i-th year; CAR ij is the carbon emission in the jth grid in year i; n is the total number of grids in each basin.

[0146] According to the basin grid parameter table from 2019 to 2023 in step S1, the horizontal and vertical coordinates of the center of each grid in each basin are determined (the coordinates of the center of the maximum inscribed circle are used for the grid with irregular boundaries); the centroid method is used to calculate the centroid coordinates of the entire basin:

[0147] The horizontal and vertical coordinates of the annual discharge center of gravity in Basin 1:

[0148]

[0149] X 2021 =4.333;X 2022 =4.314;X 2023 =4.285;

[0150] Y 2020 =7.283; Y 2021 =7.237; Y 2022 =7.218; Y 2023 =7.281;

[0151] The horizontal and vertical coordinates of the annual discharge center of gravity in Basin 2:

[0152] X 2020 =11.742;X 2021 =11.725;X 2022 =11.748;X 2023 =11.752;

[0153] Y 2020 =11.190;Y 2021 =11.226; Y 2022 =11.217; Y 2023 =11.235;

[0154] Then connect the centroid coordinates of the two basins calculated by the centroid method to obtain the centroid distance between the two basins ( Figure 5 The centroid distances were standardized and the standardized distances were 0.497, 0.500, 0.502 and 0.500 respectively.

[0155] Step S5: construct the “natural-economic-social” comprehensive impact index of each basin based on the time series data of the “natural-economic-social” factors of the basin;

[0156] The present invention adopts the improved CRITIC method to calculate the "nature-economy-society" comprehensive impact index. The improved CRITIC method can fully consider the variability and conflict between the 12 "nature-economy-society" factors selected in step S1, so that the weighting of each factor is more scientific, and then the "nature-economy-society" comprehensive impact index is calculated. The specific steps are:

[0157] Step S501: construct an initial factor matrix:

[0158]

[0159] Step S502: Standardize the “nature-economy-society” factor data to obtain a standardized matrix:

[0160]

[0161] Among them, for a certain river basin, a ij , a′ ij are the jth “natural-economic-social” factor in the i-th year before and after standardization, respectively;

[0162] Step S503: Calculate the variability of each factor based on the standardized "nature-economy-society" factor. Variability refers to the volatility of the same factor under time changes. The larger the value, the stronger the volatility of the factor over time, so the greater the weight assigned. The specific formula is as follows:

[0163]

[0164] Among them, E j is the variation index of the jth “nature-economy-society” factor; a′ ij is the jth “nature-economy-society” factor in the i-th year after standardization; is the average value of the jth factor; m is the number of factors;

[0165] Step S504: Pearson correlation coefficient method is used to calculate the correlation between the “nature-economy-society” factors, and then the conflict between the factors is calculated. The conflict between the factors refers to the degree of association between different factors. The greater the conflict between two factors, the weaker the association between the two factors, and the more different points of information reflected, so the greater the weight assigned. The specific formula is as follows:

[0166]

[0167] Among them, R j is the conflict index of the jth “nature-economy-society” factor; |r qj| is the absolute value of the Pearson correlation coefficient between the qth factor and the jth factor; m is the number of factors;

[0168] Step S505: Calculate the weight of each factor according to the variation index and conflict index of each "nature-economy-society" factor. The specific formula is as follows:

[0169]

[0170] Among them, W j is the weight of the jth “nature-economy-society” factor; E j is the variation index of the jth “nature-economy-society” factor; R j is the conflict index of the jth “nature-economy-society” factor; m is the number of factors;

[0171] Step S506: Calculate the “Nature-Economy-Society” comprehensive impact index according to the weights of each “Nature-Economy-Society” factor. The specific formula is as follows:

[0172]

[0173] Among them, V z is the comprehensive impact index of “nature-economy-society” of the zth basin; W j is the weight of the jth “nature-economy-society” factor; a′ ij is the jth “natural-economic-social” factor in the i-th year after standardization; m is the number of factors.

[0174] According to the "nature-economy-society" factors selected in step S1: Nature: mainstream flow of the basin, average annual precipitation, vegetation coverage, number of species in the basin; Economy: GDP of the basin, average utilization rate of basin resources, export trade volume of the basin, and flow of ecological compensation funds; Society: population flow, basin logistics, mileage of basin roads, and urbanization rate data, construct the initial "nature-economy-society" factor matrix from 2020 to 2023:

[0175] Basin 1:

[0176]

[0177] Watershed 2:

[0178]

[0179] The standardized matrix is ​​obtained by standardizing the “nature-economy-society” factor data. The standardized matrix is ​​as follows:

[0180] Basin 1:

[0181]

[0182] Watershed 2:

[0183]

[0184] Then, the variation index of each factor is calculated based on the standardized "natural-economic-social" factors:

[0185] For example, the variation index of the main stream flow of Basin 1 is:

[0186]

[0187]

[0188] According to the correlation between the “nature-economy-society” factors, the conflict index of each factor is calculated. The Pearson correlation coefficient is as follows: Figure 7 As shown:

[0189] For example, the conflict index of the main stream flow of Basin 1 is:

[0190]

[0191] Then, the weight of each factor is calculated according to the variation index and conflict index of each "natural-economic-social" factor in the two basins:

[0192] For example, the weight of the main stream flow of Basin 1 is:

[0193]

[0194] Then, according to the weight of each "nature-economy-society" factor, the annual "nature-economy-society" comprehensive impact index of the two basins is calculated:

[0195] For example, the comprehensive impact index of “Nature-Economy-Society” in Basin 1 in 2020 is:

[0196]

[0197] Step S6: Based on the coupling degree of each river basin, the comprehensive impact index of "nature-economy-society" and the distance between the centers of gravity, the gravitational intensity of pollution reduction and carbon reduction between river basins is calculated.

[0198] In this embodiment, the specific formula used to calculate the gravitational strength of pollution reduction and carbon reduction between river basins is as follows:

[0199]

[0200]

[0201] Among them, G ijis the gravitational strength of basin i on basin j. The larger the value, the stronger the relationship, influence and coupling effect between basins in reducing pollution and carbon emissions. ij is the gravity coefficient of basin i to basin j; C i , C j are the coupling degrees of basin i and basin j respectively; V i 、V j D is the comprehensive impact index of “nature-economy-society” of basin i and basin j; ij is the straight-line distance from the centroid of the watershed.

[0202] In this embodiment, the gravity strength of basin 1 on basin 2 is calculated by first calculating the gravity coefficient of basin 1 on basin 2 every year:

[0203] 2020:

[0204] 2021: C 12 =0.498;

[0205] 2022: C 12 =0.520;

[0206] 2023: C 12 =0.506;

[0207] Then, based on the gravity coefficient of Basin 1 to Basin 2, combined with the annual "natural-economic-social" comprehensive impact index, coupling degree and basin center distance, the gravity intensity of Basin 1 to Basin 2 is calculated each year:

[0208] 2020:

[0209] 2021: G 12 =36.339;

[0210] 2022: G 12 =8.896;

[0211] 2023: G 12 =18.706.

[0212] The results show that the gravitational pull of Basin 1 on Basin 2 is strongest in 2021 and weakest in 2022, showing an overall fluctuating development trend.

[0213] This embodiment first presets the raster datasets of the two river basins from 2019 to 2023 (the parameters of each raster include pollutant emissions, carbon emissions, and central coordinates) and the "natural-economic-social" factor datasets of the two river basins (including: natural: river basin mainstream flow, average annual precipitation, vegetation coverage, and number of species in the river basin; economic: river basin GDP, average utilization rate of river basin resources, river basin export trade volume, and ecological compensation fund flow; social: population mobility, river basin logistics, river basin road mileage, and urbanization rate). The coupling degree and synergy method are used to calculate the coupling synergy of pollution reduction and carbon reduction in the two river basins, clearly evaluate the coupling relationship of pollution reduction and carbon reduction in the river basins, and accurately judge the synergy dominant relationship; combined with the "natural-economic-social" comprehensive impact index, coupling degree, and the distance between the pollutant and carbon emission centers of gravity, the gravitational intensity between the two river basins is analyzed and calculated, which can help understand the radiation relationship between pollution reduction and carbon reduction between river basins, and is conducive to promoting coordinated cooperation in pollution reduction and carbon reduction between river basins, and providing a scientific basis for the formulation of pollution reduction and carbon reduction policies between river basins.

[0214] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and a watershed gravity, characterized in that: The following steps are involved: Step S1: Obtain multi-year time series data of pollutants and carbon emissions in the watershed at the grid scale; obtain the time series data of the "natural-economic-social" factors of the watershed; accumulate the pollutant and carbon emission data in the grid of each watershed each year to obtain the total amount of pollutants and carbon emissions in each watershed in that year; calculate the annual reduction / increase of pollutants and carbon emissions based on the multi-year time series data of pollutants and carbon emissions; Step S2: Standardize the annual pollutant and carbon emission reduction / increase data; use the coupling degree model to calculate the coupling degree between pollution reduction and carbon reduction in each river basin based on the standardized data set, and then obtain the pollution reduction and carbon reduction coupling degree level of each river basin; Step S3: Based on the annual pollutant data and carbon emission reduction / increase data, the pollution reduction and carbon reduction synergy efficiency coefficient is used to calculate the synergy between pollution reduction and carbon reduction in each river basin; and then combined with the coupling degree between pollution reduction and carbon reduction in each river basin obtained in step S2, the pollution reduction and carbon reduction coupling synergy status of each river basin is quantitatively evaluated; Step S4: Determine the centroid coordinates of pollutants and carbon emissions in each river basin according to the center coordinates of each grid and the pollutant and carbon emission data in each grid; connect the centroid coordinates of two river basins to obtain the straight-line distance between the centroids of the two river basins and standardize the straight-line distance data; Step S5: Construct the comprehensive impact index of "nature-economy-society" of each river basin based on the time series data of "nature-economy-society" factors of the river basin; Step S6: Based on the coupling degree of each river basin, the "natural-economic-social" comprehensive impact index and the straight-line distance between the centers of gravity, the gravitational intensity of pollution reduction and carbon reduction between river basins is calculated.

2. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed according to claim 1 is characterized in that: In step S1, the watershed "natural-economic-social" factor time series data includes: Natural factors: mainstream flow, annual average precipitation, vegetation coverage, and number of species in the basin; mainstream flow and annual average precipitation reflect the intensity of the flow of pollutants and carbon between basins with water as the medium; vegetation coverage reflects the carbon storage capacity between basins; and the number of species in the basin reflects the degree of negative impact of pollutants and carbon on the basin; Economic factors: GDP of the river basin, average utilization rate of river basin resources, export trade volume of the river basin, and flow of ecological compensation funds; among them, GDP of the river basin and average utilization rate of river basin resources reflect the emission intensity of pollutants and carbon in the river basin, export trade volume of the river basin reflects the circulation intensity of pollutants and carbon between river basins with economic exchange as the medium; flow of ecological compensation funds reflects the intensity of ecological governance in the river basin; Social factors: population mobility, basin logistics volume, basin road mileage, and urbanization rate. Among them, population mobility, basin logistics volume, and basin road mileage reflect the circulation intensity of pollutants and carbon between basins with people and objects as the medium; the urbanization rate reflects the emission intensity of pollutants and carbon in the basin.

3. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the watershed gravity according to claim 1 is characterized in that: In step S1, the total amount of pollutants and the total amount of carbon emissions are calculated as follows: Among them, POL i is the total amount of pollutant emissions in year i; POL ij is the emission of pollutants in the jth grid in the i-th year; CAR i is the total carbon emissions in year i; CAR ij is the carbon emission in the jth grid in year i; n is the total number of grids in each basin.

4. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the watershed gravity according to claim 3 is characterized in that: In step S1, the annual reduction / increase in pollutant and carbon emissions is calculated. The specific calculation formula is: ΔPOL i =POL i-1 -POL i ; ΔCAR i =CAR i-1 -CAR i ; Where, ΔPOL i is the difference in pollutant emissions between year i and year (i-1), where ΔPOL i >0 means pollutant emission reduction, ΔPOL i <0 means pollutant emission increase; POL i-1 is the total amount of pollutant emissions in year (i-1); POL i is the total amount of pollutant emissions in year i; ΔCAR i is the difference in carbon emissions between year i and year (i-1), where ΔCAR i >0 means carbon reduction, ΔCAR i <0 means carbon emission increase; CAR i-1 is the total carbon emissions in year (i-1), CAR i is the total carbon emissions in year i.

5. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed according to claim 4 is characterized in that: In step S2, the specific formula for normalizing the pollutant and carbon emission reduction / increase data is as follows: Among them, U is the standardized reduction / increase of pollutant emissions, ΔPOL i is the reduction / increase of pollutant emissions before standardization, B is the reduction / increase of carbon emissions after standardization, ΔCAR i is the reduction / increase of carbon emissions before normalization, and k is the total number of pollutant data.

6. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed according to claim 5 is characterized in that: In step S2, the coupling degree model is: Among them, C i is the coupling degree of pollution reduction and carbon reduction in the i-th year, and its value range is [0,1]; C i The closer it is to 1, the higher the coupling degree; i is the difference of pollutant emissions in the i-th year after standardization; B i is the standardized carbon emission difference in year i.

7. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed according to claim 6 is characterized in that: In step S3, the synergy efficiency coefficient of pollution reduction and carbon reduction is used to calculate the synergy between pollution reduction and carbon reduction in each river basin. The specific formula is as follows: Among them, S i is the coordination degree of pollution reduction and carbon reduction in the i-th year; ΔPOL i POL is the difference in pollutant emissions between year i and year (i-1); i is the total amount of pollutant emissions in year i; ΔCAR i is the difference in carbon emissions between year i and year (i-1); CAR i is the total carbon emissions in year i; S i The value range is (-∞,+∞), when S i When <0, it means that pollution reduction and carbon reduction are not coordinated; when 0≤S i When <0.8, it indicates synergy dominated by carbon reduction; when 0.8≤S i When S is ≤1.2, it indicates the synergy of pollution reduction and carbon reduction. i When it is >1.2, it indicates coordination dominated by pollution reduction.

8. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed according to claim 7 is characterized in that: In step S4, the centroid method is used to determine the centroid of pollutants and carbon emissions in each river basin. The specific formula is as follows: Among them, X i , Y i are the horizontal and vertical coordinates of the center of gravity of pollutants and carbon emissions in the basin in year i, respectively; j ,y j is the horizontal and vertical coordinates of the jth grid cell; POL ij is the emission of pollutants in the jth grid in the i-th year; CAR ij is the carbon emission in the jth grid in year i; n is the total number of grids in each basin.

9. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the watershed gravity according to claim 8, characterized in that: In step S5, the improved CRITIC method is used to calculate the "nature-economy-society" comprehensive impact index. The improved CRITIC method can fully consider the variability and conflict between the 12 "nature-economy-society" factors selected in step S1, and then calculate the "nature-economy-society" comprehensive impact index. The specific steps are: Step S501: construct an initial factor matrix: Step S502: Standardize the "nature-economy-society" factor data to obtain a standardized matrix: Among them, for a certain river basin, a ij , a i ' j are the jth "natural-economic-social" factor in the i-th year before and after standardization, respectively; Step S503: Calculate the variability of each factor based on the standardized "natural-economic-social" factor, where the so-called variability refers to the volatility of the same factor under time changes. The larger the value, the stronger the volatility of the factor over time, and the greater the weight assigned. The specific formula is as follows: Among them, E j is the variation index of the jth "nature-economy-society" factor; a i ' j is the jth "natural-economic-social" factor in the i-th year after standardization; is the average value of the jth factor; m is the number of factors; Step S504: Pearson correlation coefficient method is used to calculate the correlation between the "nature-economy-society" factors, and then the conflict between the factors is calculated. The conflict between the factors refers to the degree of association between different factors. The greater the conflict between two factors, the weaker the association between the two factors, and the more different points of information reflected, so the greater the weight assigned. The specific formula is as follows: Among them, R j is the conflict index of the jth "nature-economy-society" factor; |r qj | is the absolute value of the Pearson correlation coefficient between the qth factor and the jth factor; m is the number of factors; Step S505: Calculate the weight of each factor according to the variation index and conflict index of each "nature-economy-society" factor. The specific formula is as follows: Among them, W j is the weight of the jth "nature-economy-society" factor; E j is the variation index of the jth "nature-economy-society" factor; R j is the conflict index of the jth "nature-economy-society" factor; m is the number of factors; Step S506: Calculate the comprehensive impact index of "nature-economy-society" according to the weights of each "nature-economy-society" factor. The specific formula is as follows: Among them, V z is the comprehensive impact index of "nature-economy-society" of the zth basin; W j is the weight of the jth "nature-economy-society" factor; a i ' j is the jth "natural-economic-social" factor in the i-th year after standardization; m is the number of factors.

10. The method for evaluating the coupled synergy relationship of pollution reduction and carbon reduction in a watershed and the gravity of a watershed according to claim 9, characterized in that: In step S6, the calculation formula of gravitational strength is: Among them, G ij is the gravitational strength of basin i on basin j. The larger the value, the stronger the relationship, influence and coupling effect between basins in reducing pollution and carbon emissions. ij is the gravity coefficient of basin i to basin j; C i , C j are the coupling degrees of basin i and basin j respectively; V i 、V j D is the comprehensive impact index of "nature-economy-society" of basin i and basin j; ij is the straight-line distance from the centroid of the watershed.

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