A method and system for determining the carbon neutrality effect of land cover type transfer

Abstract

The present invention discloses a method and system for determining the carbon neutrality effect of land cover type transfer, which relates to the application field of ecological environment change monitoring, and the method comprises: calculating the average carbon fixation value according to the vegetation net primary productivity data set in the study period; comparing the land cover types in the first year and the target year to determine the evolution zone of the target area; calculating the carbon fixation of each pixel in the evolution zone in the first year according to the average carbon fixation value in the study period by using the neighborhood proxy method; calculating the carbon fixation change value of each pixel in the evolution zone in the study period according to the carbon fixation of each pixel in the evolution zone in the first year and the carbon fixation of each pixel in the evolution zone in the study period; constructing the carbon neutrality effect matrix of the target area in the study period based on the carbon fixation change value of all pixels in the evolution zone in the study period. The present invention can accurately depict the changes in the carbon neutrality effect brought about by the transfer of different land cover types.

Description

Technical Field

[0001] The present invention relates to the application field of ecological environment change monitoring, and in particular to a method and system for determining the carbon neutrality effect of surface cover type transfer. Background Art

[0002] Terrestrial ecosystems have a huge carbon fixation capacity and will play the role of "ballast stone" and "stabilizer" in the "dual carbon" action. However, under the influence of comprehensive factors, different surface cover types of terrestrial ecosystems will transfer to each other, which will bring about changes in carbon storage in terrestrial ecosystems, leading to "carbon loss" or "carbon sink", and changing the carbon neutrality effect of terrestrial ecosystems. Accurately depicting the changes in carbon neutrality effects brought about by the transfer of different surface cover types is particularly important for clarifying the carbon flow direction of terrestrial ecosystems. However, there is currently no effective technology that can simply and accurately depict the changes in the carbon neutrality effect brought about by the transfer of surface cover types, which will be detrimental to the effective implementation of the "dual carbon" strategy. Therefore, proposing an effective and simple technology to accurately depict the carbon neutrality effect brought about by the transfer of surface cover types has become an urgent problem to be solved. Summary of the invention

[0003] Based on this, an embodiment of the present invention provides a method and system for determining the carbon neutrality effect of surface cover type transfer, so as to accurately characterize the changes in carbon neutrality effect brought about by the transfer of different surface cover types.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for determining the carbon neutrality effect of land cover type transfer, comprising:

[0006] Obtain the land cover type of the target area in the first year, the land cover type of the target year and the net primary productivity of vegetation in the research period; the research period includes: multiple consecutive years; the starting year of the research period is the first year, and the ending year of the research period is the target year;

[0007] Based on the vegetation net primary productivity data set during the study period, the average carbon sequestration value during the study period was calculated;

[0008] Comparing the land cover type of the first year with the land cover type of the target year, determining the evolution zone of the target area during the study period; the evolution zone is the area where the land cover type shifts;

[0009] According to the average carbon fixation amount during the study period, the carbon fixation amount of each pixel in the evolution area in the first year is calculated by using the neighborhood proxy method; the carbon fixation amount in the first year represents the carbon fixation amount of each pixel before the land cover type is transferred;

[0010] According to the net primary productivity of vegetation in the target year, the carbon sequestration amount of each pixel in the evolution area in the target year is calculated;

[0011] Calculate the carbon fixation change value of each pixel in the evolution zone during the study period according to the carbon fixation amount of each pixel in the evolution zone in the first year and the carbon fixation amount of each pixel in the evolution zone in the target year;

[0012] Based on the change values ​​of carbon fixation in all pixels in the evolution zone during the study period, a carbon neutrality effect matrix of the target area during the study period is constructed; the carbon neutrality effect matrix is ​​used to characterize the changes in carbon neutrality effect brought about by the change of surface cover type in the target area during the study period.

[0013] Optionally, according to the average carbon fixation value in the study period, the carbon fixation value of each pixel in the evolution area in the first year is calculated using the neighborhood proxy method, specifically including:

[0014] Determine any pixel in the evolution zone as a target pixel. If the surface cover type of the target pixel in the first year is the first type, and the surface cover type of the target pixel in the study period is the second type, determine all pixels whose surface cover type is the first type among the surrounding pixels of the target pixel in the target year to obtain a replacement pixel set; the surrounding pixels are pixels within a set range around the target pixel;

[0015] Extracting the average carbon fixation amount of the replacement pixel set from the average carbon fixation amount during the study period;

[0016] The average carbon sequestration amount of the replacement pixel set is determined as the carbon sequestration amount of the target pixel in the first year.

[0017] Optionally, based on the carbon fixation change values ​​of all pixels in the evolution area during the study period, a carbon neutrality effect matrix of the target area during the study period is constructed, specifically including:

[0018] Determine the carbon neutrality effect value of each pixel in the evolution area according to the change value of carbon fixation of each pixel in the study period;

[0019] According to the carbon fixation change value of each pixel in the evolution zone during the study period, the carbon fixation amount transferred in and the carbon fixation amount transferred out of each target type in the target area during the study period are calculated; the carbon fixation amount transferred in is the sum of the carbon fixation changes caused by the conversion of each surface cover type to the target type during the study period of the target area; the carbon fixation amount transferred out is the sum of the carbon fixation changes caused by the conversion of the target type to each surface cover type during the study period of the target area; the target type is any surface cover type in the target area;

[0020] Determine the input carbon neutrality effect value of each target type according to the input carbon fixation amount of each target type, and determine the output carbon neutrality effect value of each target type according to the output carbon fixation amount of each target type;

[0021] Add all types of carbon sequestration in and all types of carbon sequestration out to determine the total carbon neutrality effect value of the target area during the study period;

[0022] According to the carbon neutrality effect value of each pixel, the input carbon neutrality effect value of each target type, the output carbon neutrality effect value of each target type and the total carbon neutrality effect value of the target area in the target year, a carbon neutrality effect matrix of the target area during the study period is constructed.

[0023] Optionally, according to the carbon sequestration of each pixel in the evolution zone in the first year and the carbon sequestration of each pixel in the evolution zone in the target year, the carbon sequestration change value of each pixel in the evolution zone during the study period is calculated, specifically including:

[0024] For any pixel in the evolution zone, the carbon sequestration amount of the pixel in the target year is subtracted from the carbon sequestration amount of the pixel in the first year to obtain the carbon sequestration change value of the pixel during the study period.

[0025] Optionally, the carbon neutrality effect value of each pixel is determined according to the change value of the carbon fixation amount of each pixel in the evolution area during the study period, specifically including:

[0026] For any pixel in the evolution zone, if the change value of the carbon fixation of the pixel during the study period is greater than zero, the carbon neutrality effect value of the pixel is determined to be positive; if the change value of the carbon fixation of the pixel during the study period is less than zero, the carbon neutrality effect value of the pixel is determined to be negative; if the change value of the carbon fixation of the pixel during the study period is equal to zero, the carbon neutrality effect value of the pixel is determined to be zero.

[0027] Optionally, according to the vegetation net primary productivity dataset within the study period, the average carbon fixation amount within the study period is calculated, specifically including:

[0028] Calculate the average of the vegetation net primary productivity data set within the study period to obtain the productivity average;

[0029] Based on the productivity average, the average carbon fixation value during the study period was calculated.

[0030] Optionally, according to the net primary productivity of vegetation in the target year, the carbon sequestration amount of each pixel in the evolution area in the target year is calculated, specifically including:

[0031] According to the net primary productivity of vegetation in the target year, calculate the amount of carbon dioxide fixed by each pixel in the evolution area in the target year;

[0032] According to the amount of fixed carbon dioxide, the amount of carbon fixation of each pixel in the evolution area in the target year is calculated.

[0033] The present invention also provides a system for determining the carbon neutrality effect of land cover type transfer, comprising:

[0034] A data acquisition module is used to acquire the land cover type of the target area in the first year, the land cover type of the target year, and the net primary productivity data set of vegetation in the research period; the research period includes: a plurality of consecutive years; the starting year of the research period is the first year, and the ending year of the research period is the target year;

[0035] A carbon fixation average value calculation module is used to calculate the carbon fixation average value within the study period according to the vegetation net primary productivity data set within the study period;

[0036] An evolution zone determination module, used to compare the land cover type of the first year with the land cover type of the target year, and determine the evolution zone of the target area within the study period; the evolution zone is the area where the land cover type shifts;

[0037] A module for determining carbon fixation before transfer, for calculating the carbon fixation of each pixel in the evolution area in the first year by using a neighborhood proxy method according to the average carbon fixation value in the study period; the carbon fixation value in the first year represents the carbon fixation value of each pixel before the land cover type transfers;

[0038] A module for determining carbon sequestration after transfer, used to calculate the carbon sequestration of each pixel in the evolution area in the target year according to the net primary productivity of vegetation in the target year;

[0039] A carbon fixation change calculation module, used to calculate the carbon fixation change value of each pixel in the evolution zone during the study period according to the carbon fixation of each pixel in the evolution zone in the first year and the carbon fixation of each pixel in the evolution zone in the target year;

[0040] The carbon neutrality effect matrix construction module is used to construct the carbon neutrality effect matrix of the target area during the study period based on the change value of carbon fixation in all pixels in the evolution zone during the study period; the carbon neutrality effect matrix is ​​used to characterize the changes in carbon neutrality effect brought about by the change of surface cover type in the target area during the study period.

[0041] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0042] The embodiment of the present invention proposes a method and system for determining the carbon neutrality effect of surface cover type transfer, which calculates the average carbon fixation value based on the vegetation net primary productivity dataset within the study period; compares the surface cover types of the first year and the target year to determine the evolution zone of the target area; calculates the carbon fixation of each pixel in the evolution zone in the first year based on the average carbon fixation value using the neighborhood proxy method; calculates the carbon fixation change value of each pixel in the evolution zone during the study period based on the carbon fixation amount in the first year and the carbon fixation amount in the target year; constructs a carbon neutrality effect matrix for the target area during the study period based on the carbon fixation change values ​​of all pixels in the evolution zone during the study period. The present invention can accurately characterize the changes in carbon neutrality effects brought about by the transfer of different surface cover types, and is simple and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 A flow chart of a method for determining the carbon neutrality effect of land cover type transfer provided in an embodiment of the present invention;

[0045] Figure 2 A schematic diagram of a carbon neutrality effect matrix provided by an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the comprehensive carbon neutrality effect of the mutual transfer of surface cover types in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020;

[0047] Figure 4 Structural diagram of the system for determining the carbon neutrality effect of surface cover type transfer provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] The purpose of the present invention is to provide a method for determining the carbon neutrality effect of land cover type transfer, so as to accurately characterize the changes in carbon storage and carbon neutrality effect of terrestrial ecosystems brought about by the transfer of different land cover types.

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] First, the land cover change carbon neutral effect (LC_CNE) is introduced.

[0052] The carbon neutrality effect of land cover type transfer refers to the degree to which the increase or decrease in carbon fixation in terrestrial ecosystems caused by the transfer of land cover offsets each other. When LC_CNE is negative, it means that the increase in carbon fixation in terrestrial ecosystems caused by the transfer of land cover is not enough to offset the decrease in carbon fixation caused by it, and the carbon fixation level of the ecosystem decreases. Conversely, it means that the increase in carbon fixation in terrestrial ecosystems caused by the transfer of land cover exceeds the decrease in carbon fixation caused by it, and the carbon fixation level of the ecosystem increases.

[0053] See also Figure 1 The method for determining the carbon neutrality effect of land cover type transfer provided in this embodiment includes:

[0054] Step 101: Obtain the land cover type of the target area in the first year, the land cover type of the target year, and the net primary productivity of vegetation during the study period.

[0055] The research period includes: a plurality of consecutive years; the starting year of the research period is the first year, and the ending year of the research period is the target year. The vegetation net primary productivity data set within the research period includes: the vegetation net primary productivity of each year within the research period.

[0056] Step 102: Calculate the average carbon fixation value during the study period based on the vegetation net primary productivity data set during the study period. Specifically:

[0057] The average value of the vegetation net primary productivity data set within the study period is calculated to obtain the productivity average value; based on the productivity average value, the average carbon fixation amount within the study period is calculated.

[0058] Step 103: Compare the land cover type of the first year with the land cover type of the target year to determine the evolution zone of the target area during the study period; the evolution zone is the area where the land cover type shifts.

[0059] Step 104: Based on the average carbon fixation value during the study period, the carbon fixation value of each pixel in the evolution area in the first year is calculated using the neighborhood proxy method.

[0060] The carbon sequestration amount in the first year represents the carbon sequestration amount of each pixel before the land cover type is transferred.

[0061] The step 104 specifically includes:

[0062] 1) Determine any pixel in the evolution zone as the target pixel. If the surface cover type of the target pixel in the first year is the first type, and the surface cover type of the target pixel in the study period is the second type, determine the pixels with the first type of surface cover in the surrounding pixels of the target pixel in the target year to obtain a replacement pixel set; the surrounding pixels are the pixels within a set range around the target pixel. For example, the surrounding pixels can be pixels within a radius of 800 pixels outside the target pixel.

[0063] 2) Extracting the average carbon fixation amount of the replacement pixel set from the average carbon fixation value during the study period.

[0064] 3) Determine the average carbon sequestration amount of the replacement pixel set as the carbon sequestration amount of the target pixel in the first year.

[0065] Step 105: Calculate the carbon fixation of each pixel in the evolution area in the target year according to the net primary productivity of vegetation in the target year. Specifically:

[0066] Based on the net primary productivity of vegetation in the target year, calculate the amount of carbon dioxide fixed by vegetation in each pixel in the evolution zone in the target year; based on the amount of carbon dioxide fixed, calculate the amount of carbon sequestration by vegetation in each pixel in the evolution zone in the target year. Net primary productivity of vegetation refers to the organic matter fixed and retained by green vegetation per unit area and per unit time, which characterizes the changes in the ability of the ecosystem to capture and store carbon.

[0067] The specific calculation principle is as follows:

[0068] Studies have shown that 1kg of carbon is equivalent to 2.2kg of organic matter. Based on the relationship between the synthesis of organic matter by vegetation photosynthesis and its absorption of CO2 and release of O2

[0069] It can be seen that every 1.00kg of organic matter produced by vegetation can fix 1.63kg of CO2 and release 1.19kg of O2, and 1kg of CO2 contains 0.27kg of carbon. Based on this relationship, the annual carbon fixation and oxygen release of the ecosystem in the target area can be obtained through the total net primary productivity of vegetation, and the calculation formula is:

[0070]

[0071]

[0072] In the formula, Indicates the amount of CO2 fixed per unit area of ​​an ecosystem (g / m 2 ), W c Indicates the carbon fixation per unit area of ​​the ecosystem (g / m 2 ), NPP refers to the net primary productivity of vegetation per unit area per year in the ecosystem (g C / m 2 ).

[0073] Step 106: Calculate the carbon fixation change value of each pixel in the evolution zone during the study period based on the carbon fixation amount of each pixel in the evolution zone in the first year and the carbon fixation amount of each pixel in the evolution zone in the target year.

[0074] Specifically, for any pixel in the evolution zone, the carbon sequestration amount of the pixel in the target year is subtracted from the carbon sequestration amount of the pixel in the first year to obtain the carbon sequestration change value of the pixel during the study period.

[0075] Step 107: Based on the carbon fixation change values ​​of all pixels in the evolution zone during the study period, construct a carbon neutrality effect matrix of the target area during the study period.

[0076] The carbon neutrality effect matrix is ​​used to characterize the changes in the carbon neutrality effect brought about by the transfer of the land cover type in the target area during the study period. For example, when the ecosystem is converted from farmland to forest or from forest to farmland, the carbon neutrality effect caused by this phenomenon can be clarified by using the method of the embodiment of the present invention. In particular, when the carbon neutrality effect is negative, the land cover type that has been transferred can be traced back, and corresponding protection measures can be implemented to avoid corresponding events in the future, ultimately promoting ecosystem carbon neutrality and helping to achieve the "dual carbon" goal.

[0077] The step 107 specifically includes:

[0078] 1) Determine the carbon neutrality effect value of each pixel according to the change value of carbon fixation of each pixel in the evolution area during the study period, so as to determine the carbon neutrality effect value at the pixel scale. Specifically:

[0079] For any pixel in the evolution zone, if the carbon fixation change value of the pixel during the study period is greater than zero, the carbon neutrality effect value of the pixel is determined to be positive; if the carbon fixation change value of the pixel during the study period is less than zero, the carbon neutrality effect value of the pixel is determined to be negative; if the carbon fixation change value of the pixel during the study period is equal to zero, the carbon neutrality effect value of the pixel is determined to be zero. The expression of the carbon neutrality effect value LC_CNE(x,y) of the pixel (x,y) is:

[0080]

[0081] LC_WC(x,y)=WC Post (x,y)-WC Pre (x,y) (4)

[0082] Among them, LC_WC is the change in carbon fixation caused by the change of land cover type, x and y are the longitude and latitude of the center of a pixel, and WC Post is the amount of carbon sequestered after the land cover type is shifted (i.e. in the target year), WC Pre It is the carbon sequestration amount before the transfer of surface cover type (i.e. in the first year), LC_CNE is the carbon neutrality effect value caused by the transfer of surface cover type. A positive value indicates that the transfer of surface cover type in the pixel has brought about an increase in carbon sequestration, which is helpful to achieve the carbon neutrality goal and presents a positive carbon neutrality effect. A negative value indicates that the transfer of surface cover type in the pixel has brought about a decrease in carbon sequestration, which is not conducive to the realization of carbon neutrality goal and presents a negative carbon neutrality effect. A value of zero indicates that the transfer of surface cover type in the pixel has achieved carbon neutrality.

[0083] 2) According to the carbon fixation change value of each pixel in the evolution zone during the study period, calculate the carbon fixation amount transferred in and out of each target type in the target area during the study period; the carbon fixation amount transferred in is the sum of the carbon fixation changes caused by the conversion of each surface cover type in the target area to the target type during the study period; the carbon fixation amount transferred out is the sum of the carbon fixation changes caused by the conversion of the target type to each surface cover type in the target area during the study period; the target type is any surface cover type in the target area. The expressions for the carbon fixation amount transferred in and out are:

[0084]

[0085]

[0086]

[0087] Among them, LC i refers to the land cover type in the first year of the study period, LC j is the land cover type in the target year, It is the sum of the carbon sequestration changes of all pixels that have undergone a specific land cover type transfer during the study period. in The change in carbon sequestration caused by the conversion of other types of land cover to a certain land cover type during the study period, LC_WC out It is the change in carbon sequestration caused by the conversion of a certain land cover type to other land cover types during the study period, and n is the maximum number of land cover types in a certain area.

[0088] 3) Determine the carbon neutrality effect value of each target type based on the carbon sequestration amount of each target type, and determine the carbon neutrality effect value of each target type based on the carbon sequestration amount of each target type. This step realizes the determination of the carbon neutrality effect value at the scale of surface cover type.

[0089] 4) Add all types of carbon sequestration inputs to all types of carbon sequestration outputs to determine the total carbon neutrality effect value of the target area in the target year, thereby determining the carbon neutrality effect value at the regional scale. The expression for the total carbon neutrality effect value is:

[0090]

[0091] LC_CNE is the total carbon neutrality effect value brought about by the transfer of surface cover types in the target area during the study period. A positive value indicates that the transfer of surface cover types in the region has brought about an increase in carbon fixation, which is conducive to the realization of the carbon neutrality goal and presents a positive carbon neutrality effect. A negative value indicates that the transfer of surface cover types in the region has brought about a decrease in carbon fixation, which is not conducive to the realization of the carbon neutrality goal and presents a negative carbon neutrality effect. A value of zero indicates that the transfer of surface cover types in the region has achieved carbon neutrality.

[0092] 5) Based on the carbon neutrality effect value of each pixel (pixel scale), the carbon neutrality effect value of each target type (land cover type scale), the carbon neutrality effect value of each target type (land cover type scale) and the total carbon neutrality effect value of the target area in the target year (regional scale), the carbon neutrality effect matrix of the target area in the target year is constructed. The carbon neutrality effect value of each pixel is as follows: Figure 2 As shown in part (a) of the table, the carbon neutrality effect values ​​of each target type are as follows: Figure 2 As shown in part (b) of the table, the carbon neutrality effect values ​​of each target type are as follows: Figure 2 As shown in part (c) of the Target Area, the total carbon neutrality effect value in the target year is as follows: Figure 2 As shown in part (d) of .

[0093] The method for determining the carbon neutrality effect of surface cover type transfer in the above embodiment is further described in detail below.

[0094] The idea of ​​constructing the carbon neutrality effect matrix of land cover type transfer in this specific example is as follows: for a certain study area, on the basis of the land cover type transfer matrix, the changes in carbon fixation of each land cover type before the land cover type transfer (Pre_WC) and after the land cover type transfer (Post_WC) are coupled, and by comparing the difference between Pre_WC and Post_WC, the increase in carbon fixation is taken as the positive effect of carbon neutrality, and the decrease in carbon fixation is taken as the negative effect of carbon neutrality, thereby constructing the carbon neutrality effect matrix of land cover type transfer. The carbon neutrality effect matrix constructed in this embodiment can be used to quantitatively study the carbon neutrality effect brought about by the interactive evolution of different land cover types, and finally comprehensively evaluate the comprehensive impact of land cover type transfer on the carbon neutrality of terrestrial ecosystems in the study area.

[0095] First, the data sources used in this specific example are explained.

[0096] The vegetation NPP used in this specific example comes from the global annual 500-meter vegetation net primary productivity dataset (GLASS_NPP) obtained from the 2019 global ecological environment remote sensing monitoring released by the National Remote Sensing Center of the Ministry of Science and Technology of the People's Republic of China, covering the period from 2001 to 2018. This product is simulated by the optimized EC-LUE model. According to the research records of ZhengY (2020), the optimized EC-LUE model performs well in simulating the spatiotemporal changes of global vegetation productivity, with higher simulation accuracy than the original EC-LUE model and other LUE models, providing a set of long-term, high-resolution and reliable global vegetation production estimation products.

[0097] The land cover data used in this specific example comes from the global land cover remote sensing mapping product (GlobeLand30) developed by the National Basic Geographic Information Center of China. It has a spatial resolution of 30 meters and provides data for 3 years in 2000, 2010, and 2020, including 10 types of land cover, such as cultivated land and forests. This product has been widely used in the study of the evolution of ecosystems in different parts of the world, and the product has a high degree of credibility. This specific example uses data from the Guangdong-Hong Kong-Macao Greater Bay Area in 2000 and 2020, with a total of 8 types of land cover, including cultivated land, forest land, grassland, shrub land, wetland, water body, impervious surface and others.

[0098] Secondly, the neighborhood proxy method used is explained in detail.

[0099] Since this specific example aims to obtain the carbon sequestration and its value changes caused by the transfer of land cover types in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020, it is necessary to remove the influence of factors other than land cover type transfer and obtain the value of vegetation NPP before and after the land cover type transfer in the land cover type transfer area as accurately as possible. Among them, this specific example obtains the land cover type transfer in the study area by comparing the difference in GlobeLand30 product data in 2000 and 2020, and uses GLASS_NPP in 2018 to represent the vegetation NPP after the land cover type transfer (i.e., the current vegetation NPP, Post_NPP). In addition, in order to remove the impact of comprehensive external factors such as climate change on vegetation NPP, this specific example first obtained the average GLASS_NPP from 2001 to 2018 to represent the vegetation NPP in the study area under natural conditions, and further used the neighborhood proxy method to obtain the vegetation NPP before the surface cover transfer in the surface cover type transfer area (i.e., the vegetation NPP in the natural state without the effect of surface cover type transfer, Pre_NPP).

[0100] The neighborhood proxy method was proposed by Imhoof in 2004 and is mainly used to study the impact of urban expansion on vegetation NPP. This method is based on the first law of geography, which holds that the surface of other land cover types near a certain land cover type is the best representation of the land conditions before the transformation of the land cover type. There is a complex "n to n" evolution relationship in the transfer of land cover types, that is, a certain land cover type may evolve into multiple other land cover types, and multiple other land cover types may also evolve into the same land cover type at the same time. For this reason, this specific example expands the application field of the neighborhood proxy method to the complex evolution process of multiple types of land cover types.

[0101] Specifically for a certain land cover type, assuming that the cultivated land pixel A is expanded by occupying the forest, then the carbon sequestration of pixel A is replaced by the average carbon sequestration of all forest pixels within a radius of 800 pixels outside pixel A, so as to obtain the vegetation carbon sequestration of pixel A before the cultivated land evolution (Pre_WC). The specific operation process is as follows:

[0102] S1, obtain two periods of land cover data (t1 and t n ) and obtain the average distribution data of NPP of terrestrial ecosystem vegetation during the period;

[0103] S2, based on t1 to t n The average distribution data of NPP of terrestrial ecosystem vegetation during the period were calculated using the above formula (1) and formula (2) to obtain the average distribution data of carbon fixation in terrestrial ecosystems:

[0104] S3, by comparing the land cover data of the two periods (t1 and t n ), to obtain the areas where the land cover evolved and did not evolve during the period;

[0105] S4, for the pixel where the land cover evolution occurs (such as pixel A), clarify the distribution of each type of land cover type (such as forest) before the land cover evolution of the pixel (t1);

[0106] S5, obtain the distribution of all forest pixels (excluding A) within a set range (such as a radius of 800 pixels) around the pixel A, and use the forest pixel distribution range to extract Further, the average terrestrial ecosystem carbon sequestration value of all forest pixels within the distribution range of the forest pixel is obtained and used to replace the terrestrial ecosystem carbon sequestration value of pixel A (A_Pre_WC);

[0107] S6, compared to t n The values ​​of carbon fixation of terrestrial ecosystem in pixel A during the period (A_Post_WC) and A_Pre_WC. When A_Post_WC is greater than A_Pre_WC, it means that from t1 to t n During this period, the evolution of land cover enhanced the carbon fixation capacity of pixel A, and pixel A showed a positive carbon neutralization effect, and vice versa, a negative carbon neutralization effect;

[0108] S7, the same treatment is performed on all pixels where land cover evolution occurs;

[0109] S8, comprehensively count the carbon neutrality effects brought about by the mutual transformation of different surface cover types, and finally obtain the carbon neutrality effect matrix of surface cover type transfer.

[0110] It is worth noting that this specific example assumes that the vegetation NPP in urban and water areas is 0.

[0111] The following is an analysis of the results of changes in carbon fixation.

[0112] Table 1 shows the carbon neutrality effect matrix of land cover type transfer in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020. Figure 3 The results of the comprehensive carbon neutrality effect of the mutual transfer of surface cover types in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020 are shown. Figure 3 It shows the changes in carbon sequestration from bare land, cities, water bodies, wetlands, shrublands, grasslands, forests, and farmland to other types.

[0113] According to Table 1 and Figure 3The results of the carbon neutrality effect matrix of land cover type transfer shown in the figure show that land cover type caused the Guangdong-Hong Kong-Macao Greater Bay Area to release 13,941.18 tons of C, reflecting a negative carbon neutrality effect. Among them, the conversion of cultivated land to forest land in the study area during the study period brought a large increase in carbon sinks to the local area, about 1,202.67 tons of C. In addition, the conversion of water bodies to cultivated land also increased carbon sinks in the study area by 1,579.31 tons of C. However, due to the occupation of impermeable surfaces and water bodies, the carbon sink in the study area lost 13,615.44 tons of C. In summary, the mutual conversion of cultivated land and other land cover types in the Guangdong-Hong Kong-Macao Greater Bay Area in the past 20 years reflects a negative carbon neutrality effect (9,522.44 tons of C were released). The conversion of forest land into impervious surfaces, water bodies, and wetlands released 6149.70 tons of C, but the conversion of forest land into grassland, cultivated land, shrubs, and bare land, and the conversion of grassland, cultivated land, water bodies, shrubs, and bare land into forest land, added 7168.65 tons of C to the Guangdong-Hong Kong-Macao Greater Bay Area, that is, the mutual conversion of land cover types increased the carbon sink of forest land in the study area (absorbing 1016.81 tons of C), reflecting a positive carbon neutralization effect. Similarly, the grassland and shrubs lost 3176.16 tons of C and 507.64 tons of C in the study area due to the encroachment of impervious surfaces, water bodies, and wetlands, respectively, but considering the mutual conversion effects of various land cover types, grassland and shrubs also showed a positive carbon neutralization effect (increasing the carbon sink by 1456.72 tons of C and 409.35 tons of C, respectively). The mutual conversion of wetlands and other land cover types released 188.52 tons of C, showing a negative carbon neutralization effect. The conversion of water bodies to other land cover types added 2633.83 tons of C to the study area, but the conversion of other land cover types to water bodies released 6256.92 tons of C. In general, water bodies showed a negative carbon neutralization effect (releasing 3623.09 tons of C). The carbon neutralization effect of impervious surfaces is mainly reflected in the reduction of carbon sinks caused by the conversion of other land cover types to impervious surfaces (releasing 17394.11 tons of C), which is the land cover type with the most obvious negative carbon neutralization effect in the study area. Finally, considering the mutual conversion effects of various land cover types, the carbon neutralization effect of bare land is negative.

[0114] Table 1 Carbon neutrality effect matrix of land cover type transfer in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020

[0115]

[0116] In order to execute the methods corresponding to the above embodiments and achieve the corresponding functions and technical effects, a system for determining the carbon neutrality effect of surface cover type transfer is provided below.

[0117] See also Figure 4 , the system comprising:

[0118] Data acquisition module 401 is used to obtain the surface cover type of the target area in the first year, the surface cover type of the target year and the vegetation net primary productivity data set within a study period; the study period includes: multiple consecutive years; the starting year of the study period is the first year, and the ending year of the study period is the target year.

[0119] The carbon fixation average value calculation module 402 is used to calculate the carbon fixation average value within the study period according to the vegetation net primary productivity data set within the study period.

[0120] The evolution zone determination module 403 is used to compare the surface cover type of the first year and the surface cover type of the target year to determine the evolution zone of the target area within the study period; the evolution zone is the area where the surface cover type shifts.

[0121] The module 404 for determining the carbon fixation amount before the transfer is used to calculate the carbon fixation amount of each pixel in the evolution zone in the first year according to the average carbon fixation amount in the study period by using the neighborhood proxy method; the carbon fixation amount in the first year represents the carbon fixation amount of each pixel before the surface cover type is transferred.

[0122] The module 405 for determining the carbon sequestration amount after transfer is used to calculate the carbon sequestration amount of each pixel in the evolution area in the target year according to the net primary productivity of vegetation in the target year.

[0123] The carbon fixation change calculation module 406 is used to calculate the carbon fixation change value of each pixel in the evolution zone during the study period based on the carbon fixation of each pixel in the evolution zone in the first year and the carbon fixation of each pixel in the evolution zone in the target year.

[0124] The carbon neutrality effect matrix construction module 407 is used to construct the carbon neutrality effect matrix of the target area in the target year based on the change value of carbon fixation of all pixels in the evolution zone during the study period; the carbon neutrality effect matrix is ​​used to characterize the changes in carbon neutrality effect brought about by the change of surface cover type in the target area during the study period.

[0125] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0126] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for determining the carbon neutrality effect of land cover type transfer, characterized in that: include: Obtain the land cover type of the first year in the target area, the land cover type of the target year, and the net primary productivity of vegetation during the study period; The research period includes: a plurality of consecutive years; the starting year of the research period is the first year, and the ending year of the research period is the target year; Based on the vegetation net primary productivity data set during the study period, the average carbon sequestration value during the study period was calculated; Comparing the land cover type of the first year with the land cover type of the target year, determining the evolution zone of the target area during the study period; the evolution zone is the area where the land cover type shifts; According to the average carbon fixation amount during the study period, the neighborhood proxy method is used to calculate the carbon fixation amount of each pixel in the evolution area in the first year; the carbon fixation amount in the first year represents the carbon fixation amount of each pixel before the land cover type is transferred; According to the net primary productivity of vegetation in the target year, the carbon sequestration amount of each pixel in the evolution area in the target year is calculated; Calculate the carbon fixation change value of each pixel in the evolution zone during the study period according to the carbon fixation amount of each pixel in the evolution zone in the first year and the carbon fixation amount of each pixel in the evolution zone in the target year; Based on the carbon fixation change values ​​of all pixels in the evolution zone during the study period, a carbon neutrality effect matrix of the target area during the study period is constructed; the carbon neutrality effect matrix is ​​used to characterize the changes in the carbon neutrality effect brought about by the transfer of the surface cover type of the target area during the study period; According to the average carbon fixation value during the study period, the neighborhood proxy method is used to calculate the carbon fixation value of each pixel in the evolution area in the first year, specifically including: Determine any pixel in the evolution zone as a target pixel. If the surface cover type of the target pixel in the first year is the first type, and the surface cover type of the target pixel in the study period is the second type, determine all pixels whose surface cover type is the first type among the surrounding pixels of the target pixel in the target year to obtain a replacement pixel set; the surrounding pixels are pixels within a set range around the target pixel; Extracting the average carbon fixation amount of the replacement pixel set from the average carbon fixation amount during the study period; The average carbon sequestration amount of the replacement pixel set is determined as the carbon sequestration amount of the target pixel in the first year.

2. A method for determining the carbon neutrality effect of land cover type transfer according to claim 1, characterized in that: Based on the carbon fixation change values ​​of all pixels in the evolution area during the study period, a carbon neutrality effect matrix of the target area during the study period is constructed, specifically including: Determine the carbon neutrality effect value of each pixel in the evolution area according to the change value of carbon fixation of each pixel in the study period; According to the carbon fixation change value of each pixel in the evolution zone during the study period, the carbon fixation amount transferred in and the carbon fixation amount transferred out of each target type in the target area during the study period are calculated; the carbon fixation amount transferred in is the sum of the carbon fixation changes caused by the conversion of each surface cover type to the target type during the study period of the target area; the carbon fixation amount transferred out is the sum of the carbon fixation changes caused by the conversion of the target type to each surface cover type during the study period of the target area; the target type is any surface cover type in the target area; Determine the input carbon neutrality effect value of each target type according to the input carbon fixation amount of each target type, and determine the output carbon neutrality effect value of each target type according to the output carbon fixation amount of each target type; Add all types of carbon sequestration in and all types of carbon sequestration out to determine the total carbon neutrality effect value of the target area during the study period; According to the carbon neutrality effect value of each pixel, the input carbon neutrality effect value of each target type, the output carbon neutrality effect value of each target type and the total carbon neutrality effect value of the target area in the target year, a carbon neutrality effect matrix of the target area during the study period is constructed.

3. The method for determining the carbon neutrality effect of land cover type transfer according to claim 1 is characterized in that: According to the carbon sequestration of each pixel in the evolution zone in the first year and the carbon sequestration of each pixel in the evolution zone in the target year, the carbon sequestration change value of each pixel in the evolution zone during the study period is calculated, specifically including: For any pixel in the evolution zone, the carbon sequestration amount of the pixel in the target year is subtracted from the carbon sequestration amount of the pixel in the first year to obtain the carbon sequestration change value of the pixel during the study period.

4. A method for determining the carbon neutrality effect of land cover type transfer according to claim 2, characterized in that: The carbon neutrality effect value of each pixel is determined according to the change value of carbon fixation of each pixel in the evolution area during the study period, specifically including: For any pixel in the evolution zone, if the change value of the carbon fixation of the pixel during the study period is greater than zero, the carbon neutrality effect value of the pixel is determined to be positive; if the change value of the carbon fixation of the pixel during the study period is less than zero, the carbon neutrality effect value of the pixel is determined to be negative; if the change value of the carbon fixation of the pixel during the study period is equal to zero, the carbon neutrality effect value of the pixel is determined to be zero.

5. The method for determining the carbon neutrality effect of land cover type transfer according to claim 1 is characterized in that: Based on the vegetation net primary productivity dataset during the study period, the average carbon sequestration value during the study period was calculated, including: Calculate the average of the vegetation net primary productivity data set within the study period to obtain the productivity average; Based on the productivity average, the average carbon fixation value during the study period was calculated.

6. A method for determining the carbon neutrality effect of land cover type transfer according to claim 1, characterized in that: According to the net primary productivity of vegetation in the target year, the carbon sequestration of each pixel in the evolution area in the target year is calculated, including: According to the net primary productivity of vegetation in the target year, calculate the amount of carbon dioxide fixed by each pixel in the evolution area in the target year; According to the amount of fixed carbon dioxide, the amount of carbon fixation of each pixel in the evolution area in the target year is calculated.

7. A system for determining the carbon neutrality effect of land cover type transfer, characterized in that: include: A data acquisition module is used to obtain the land cover type of the target area in the first year, the land cover type of the target year and the net primary productivity of vegetation during the study period; The research period includes: a plurality of consecutive years; the starting year of the research period is the first year, and the ending year of the research period is the target year; A carbon fixation average value calculation module is used to calculate the carbon fixation average value within the study period according to the vegetation net primary productivity data set within the study period; An evolution zone determination module, used to compare the land cover type of the first year with the land cover type of the target year, and determine the evolution zone of the target area within the study period; the evolution zone is the area where the land cover type shifts; A module for determining carbon fixation before transfer, for calculating the carbon fixation of each pixel in the evolution area in the first year by using a neighborhood proxy method according to the average carbon fixation value in the study period; the carbon fixation value in the first year represents the carbon fixation value of each pixel before the land cover type transfers; A module for determining carbon sequestration after transfer, used to calculate the carbon sequestration of each pixel in the evolution area in the target year according to the net primary productivity of vegetation in the target year; A carbon fixation change calculation module, used to calculate the carbon fixation change value of each pixel in the evolution zone during the study period according to the carbon fixation of each pixel in the evolution zone in the first year and the carbon fixation of each pixel in the evolution zone in the target year; A carbon neutrality effect matrix construction module is used to construct a carbon neutrality effect matrix of the target area during the study period based on the carbon fixation change values ​​of all pixels in the evolution area during the study period; the carbon neutrality effect matrix is ​​used to characterize the changes in the carbon neutrality effect brought about by the transfer of the surface cover type in the target area during the study period; According to the average carbon fixation value during the study period, the neighborhood proxy method is used to calculate the carbon fixation value of each pixel in the evolution area in the first year, specifically including: Determine any pixel in the evolution zone as a target pixel. If the surface cover type of the target pixel in the first year is the first type, and the surface cover type of the target pixel in the study period is the second type, determine all pixels whose surface cover type is the first type among the surrounding pixels of the target pixel in the target year to obtain a replacement pixel set; the surrounding pixels are pixels within a set range around the target pixel; Extracting the average carbon fixation amount of the replacement pixel set from the average carbon fixation amount during the study period; The average carbon sequestration amount of the replacement pixel set is determined as the carbon sequestration amount of the target pixel in the first year.

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