Evaluation method and system for carbon sink effect of coastal wetland

Abstract

The present application relates to a carbon stock monitoring technique, and specifically relates to an evaluation method and system for the carbon sink effect of a coastal wetland. The evaluation method comprises: acquiring a remote sensing image set, within a preset time period, of a coastal wetland to be subjected to evaluation; respectively identifying evolution data of different types of coastal wetlands in the remote sensing image set, wherein the evolution data comprises conversion data between different types of wetlands, and net change data, other than the conversion data, of each type of coastal wetland; and on the basis of the conversion data and the net change data, evaluating the carbon sink effect of the coastal wetland to be subjected to evaluation, so as to obtain a carbon sink effect evaluation result. In addition to performing qualitative analysis on a mature wetland area in the prior art, the present application further takes into comprehensive consideration factors which represent a carbon sink effect, such as evolution data and evolution types before and after the evolution of a coastal wetland to be subjected to evaluation, so as to comprehensively perform carbon sink effect evaluation on said coastal wetland, thereby more accurately obtaining the carbon sink effect of said coastal wetland.

Description

A method and system for evaluating carbon sequestration effects in coastal wetlands Technical Field

[0001] The present invention relates to the technical field of carbon storage monitoring, and more specifically, to a method and system for evaluating the carbon sequestration effect of coastal wetlands. Background Art

[0002] Due to the influence of periodic tidal inundation by seawater, coastal wetlands have a strong carbon sink function and are an important way to reduce atmospheric carbon dioxide (CO2) concentrations and mitigate global climate change. The carbon stored in these coastal wetland ecosystems is called "blue carbon." It is estimated that half of the carbon stored by living marine organisms worldwide is located in coastal blue carbon ecosystems. As an important type of coastal blue carbon ecosystem, coastal wetlands have a huge carbon absorption capacity and fall within the practice scope of "nature-based solutions". They are one of the important ocean-based climate change governance methods. Studies have shown that the annual carbon storage capacity of coastal wetlands is expected to reach 0.22GgC per square kilometer.

[0003] Current research on coastal wetland carbon sequestration often relies on measuring soil organic carbon content and the number and population of organisms in coastal wetlands. However, existing techniques for detecting carbon sequestration capacity often involve establishing sampling sites within one or more types of coastal wetlands, or using static simulation chambers. After sampling at a specific location for an extended period, the carbon sequestration capacity of that type of wetland is determined.

[0004] However, coastal wetlands are sensitive and vulnerable areas to global changes. Due to the influence of biological activities, human activities, climate and other factors, coastal wetlands are often in a state of change. For example, some coastal wetlands have disappeared, some have become artificial coastal wetlands, and some have changed their types due to human activities or biological invasions.

[0005] The carbon sequestration forms and carbon sequestration capacities of different types of coastal wetlands vary greatly. This is illustrated by taking salt marshes, mangroves, and mudflats as examples:

[0006] Among them, salt marshes and mangroves are production-type carbon sink wetlands, while mudflats are input-type carbon sink wetlands. The main carbon sink capacity of salt marshes and mangroves is often through plant photosynthesis, while mudflats receive carbon input from the surrounding areas, such as carbon input from mangroves, salt marshes or coastal seagrass beds.

[0007] Therefore, when coastal wetlands change, their carbon sequestration capacity will often change accordingly. If the carbon sequestration effect testing method in existing technology is used for testing, it is often difficult to accurately evaluate the carbon sequestration effect of coastal wetlands, and it is difficult to provide theoretical guidance for the management of native coastal wetlands.

[0008] Therefore, how to accurately evaluate the carbon sequestration effect of coastal wetlands and provide theoretical guidance for the management of coastal wetlands has become a technical problem that needs to be solved urgently.

[0009] Summary of the Invention

[0010] The purpose of the present invention is to provide a method and system for evaluating the carbon sequestration effect of coastal wetlands, so as to solve the technical problem of how to accurately evaluate the carbon sequestration effect of coastal wetlands and provide theoretical guidance for the management of coastal wetlands.

[0011] To achieve the above object, the present invention provides the following solutions:

[0012] According to the first aspect, an embodiment of the present application provides a method for evaluating the carbon sequestration effect of coastal wetlands, including: obtaining a set of remote sensing images of the coastal wetland to be evaluated within a preset time period; respectively identifying the evolution data of different types of coastal wetlands in the remote sensing image set, the evolution data including conversion data between different types of wetlands and net change data of each type of coastal wetland excluding the conversion data; evaluating the carbon sequestration effect of the coastal wetland to be evaluated based on the conversion data and the net change data to obtain a carbon sequestration effect evaluation result; wherein the carbon sequestration form and carbon sequestration effect of the coastal wetland corresponding to the conversion data are different from the carbon sequestration form and carbon sequestration effect of the coastal wetland corresponding to the net change data.

[0013] Optionally, the evolution data of respectively identifying different types of coastal wetlands in the remote sensing image set includes: respectively identifying the types of coastal wetlands in the remote sensing image set; determining the area data of each type of coastal wetland to be evaluated in each remote sensing image based on the identified types of coastal wetlands; determining the transition areas between different types of wetlands and the net change areas of each type of coastal wetland excluding the transition data according to the time sequence of the remote sensing image set and the area data; and using the transition data of the transition area and the net change data of the net change area as the evolution data.

[0014] Optionally, the carbon sequestration effect of the coastal wetland to be evaluated is evaluated based on the conversion data and the net change data to obtain a carbon sequestration effect evaluation result, including: determining a net change evaluation result based on the net change data and the type of coastal wetland that has undergone a net change, wherein the net change data is the changed area of ​​non-coastal wetlands changed to coastal wetlands or coastal wetlands changed to non-coastal wetlands and the type of the changed coastal wetlands; determining a first type of coastal wetland before the conversion and a second type of coastal wetland after the conversion and a conversion area based on the conversion data; determining a conversion evaluation result based on the conversion area using a first weight coefficient corresponding to the first type and a second weight coefficient corresponding to the second type; and taking the sum of the net change evaluation result and the conversion evaluation result as the carbon sequestration effect evaluation result.

[0015] Optionally, the types of coastal wetlands include production wetlands and input wetlands; the first type of wetlands include mangroves and / or salt marshes; the second type of wetlands include tidal flats; the first weight coefficient is a1, wherein a1 is the identification probability that the conversion area of ​​the coastal wetland is a mangrove and / or salt marsh; the second weight coefficient is b1, wherein b1 is the identification probability that the conversion area of ​​the coastal wetland is a tidal flat, and the sum of a1 and b1 is less than or equal to 1; the conversion evaluation result determined based on the conversion area using the first weight coefficient corresponding to the first type and the second weight coefficient corresponding to the second type includes: taking the product of the preset carbon sequestration capacity of the mangroves and / or salt marshes under the conversion area and the first weight coefficient as the first evaluation result in the wetland conversion process; taking the product of the preset carbon sequestration capacity of the tidal flats under the conversion area and the second weight coefficient as the second evaluation result in the wetland conversion process; and taking the sum of the first evaluation result and the second evaluation result as the conversion evaluation result.

[0016] Optionally, the first type of wetland includes mudflats; the second type of wetland includes mangroves and / or salt marshes; the first weight coefficient is 1+b2, wherein b2 is the identification probability that the conversion area of ​​the coastal wetland is a mudflat; the second weight coefficient is a2, wherein a2 is the identification probability that the conversion area of ​​the coastal wetland is a mangrove and / or salt marsh, and the sum of a2 and b2 is less than or equal to 1; the conversion evaluation result determined based on the conversion area using the first weight coefficient corresponding to the first type and the second weight coefficient corresponding to the second type includes: taking the product of the preset carbon sequestration capacity of the mudflat under the conversion area and the first weight coefficient as the third evaluation result in the wetland conversion process; taking the product of the preset carbon sequestration capacity of the mangroves and / or salt marsh under the conversion area and the second weight coefficient as the fourth evaluation result in the wetland conversion process; and taking the sum of the third evaluation result and the fourth evaluation result as the conversion evaluation result.

[0017] Optionally, the first weight coefficient is c times 1+b2, where c is the increase factor of deposition efficiency and c is greater than 1.

[0018] Optionally, the first weight coefficient and the second weight coefficient are adjusted based on the duration of the conversion, wherein the longer the duration of the distance conversion occurs, the smaller the first weight coefficient is, and the larger the second weight coefficient is.

[0019] Optionally, the method further includes: respectively identifying different types of coastal wetland areas in the remote sensing image set; obtaining environmental information within the preset time period; and adjusting the carbon sequestration effect assessment result based on the environmental information.

[0020] Optionally, the environmental information includes temperature information; the adjusting the carbon sink effect evaluation result based on the environmental information includes: determining the organic carbon decomposition coefficient based on the temperature information; adjusting the carbon sink effect evaluation result based on the decomposition coefficient; and / or, the environmental information includes the spring rainfall; the adjusting the carbon sink effect evaluation result based on the environmental information includes: determining the organic carbon generation coefficient based on the spring rainfall; adjusting the carbon sink effect evaluation result based on the organic carbon generation coefficient.

[0021] According to the second aspect, an embodiment of the present application provides a coastal wetland carbon sequestration effect evaluation system, including: an acquisition module for acquiring a set of remote sensing images of the coastal wetland to be evaluated within a preset time period; an identification module for respectively identifying the evolution data of different types of coastal wetlands in the remote sensing image set, the evolution data including conversion data between different types of wetlands and net change data of each type of coastal wetland excluding the conversion data; an evaluation module for evaluating the carbon sequestration effect of the coastal wetland to be evaluated based on the conversion data and the net change data to obtain a carbon sequestration effect evaluation result; wherein the carbon sequestration form and carbon sequestration effect of the coastal wetland corresponding to the conversion data are different from the carbon sequestration form and carbon sequestration effect of the coastal wetland corresponding to the net change data.

[0022] When evaluating the carbon sequestration effect of the coastal wetlands to be evaluated, especially when evaluating wetlands in areas with more frequent changes, the above-mentioned method and system of the present invention, in addition to the qualitative analysis of mature wetland areas in the existing technology, also comprehensively considers the evolution data of the coastal wetlands to be evaluated, and considers the evolution type, wetland type before and after evolution, carbon sequestration form before and after evolution, carbon sequestration capacity before and after evolution, carbon sequestration amount before and after evolution and other factors that characterize the carbon sequestration effect to comprehensively evaluate the carbon sequestration effect of the coastal wetlands to be evaluated, which can more accurately obtain the carbon sequestration effect of the wetlands to be evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] FIG1 shows a flow chart of a method for evaluating carbon sequestration effects of coastal wetlands according to the present invention;

[0025] FIG2 shows a flow chart of another coastal wetland carbon sequestration effect assessment method of the present invention;

[0026] FIG3 shows a schematic diagram of the coastal wetland carbon sequestration effect evaluation system of the present invention. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described with reference to the accompanying drawings. In the drawings, the same reference numerals represent components with the same structure or similar structures but the same functions.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0029] In the following description, various aspects of the present invention will be described. However, it will be apparent to those skilled in the art that the present invention may be practiced utilizing only some or all of the structures or processes of the present invention. Specific numbers, configurations, and sequences are described for clarity of explanation, but it is apparent that the present invention may be practiced without these specific details. In other cases, well-known features will not be described in detail to avoid obscuring the present invention.

[0030] Referring to the background technology, the existing technology often evaluates the carbon sequestration effect based on mature coastal wetlands. The evaluation of the carbon sequestration effect of mature coastal wetlands is often more accurate. However, coastal wetlands are relatively sensitive and fragile ecological environments. Some external factors, such as climate, human activities, and biological invasions, may cause major changes in coastal wetlands. Therefore, when using the existing technology to conduct qualitative analysis of mature coastal wetlands, if the type of coastal wetlands changes, the evaluation results are often not accurate enough. Therefore, the inventors found that coastal wetlands can be divided into mature areas and changing areas. The mature areas can be evaluated using the evaluation method of qualitative analysis of mature coastal wetlands in the existing technology. When evaluating the carbon sequestration effect of the changing areas, if the evaluation method of qualitative analysis of mature coastal wetlands in the existing technology is used, the evaluation results are often not accurate enough, especially for coastal wetlands with obvious changes. Therefore, in this application, the inventors divide the changing areas into net change areas and conversion areas. On the basis of the mature coastal wetland carbon sink effect evaluation method, the evaluation of net change areas and conversion areas is added to more accurately evaluate the carbon sequestration effect of the coastal wetlands to be evaluated.

[0031] Therefore, the present invention provides a method for evaluating the carbon sequestration effect of coastal wetlands, which can achieve accurate estimation of the carbon sequestration effect of coastal wetland ecosystems.

[0032] 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.

[0033] FIG1 is a flow chart of a method for evaluating carbon sequestration effects of coastal wetlands according to an embodiment of the present invention. As shown in the figure, the method includes:

[0034] S10. Acquire a set of remote sensing images of the coastal wetland to be assessed within a preset time period. In this embodiment, the preset time period can be a time period of various dimensions, such as six months, one year, two years, three years, five years, or ten years. This is not a limitation in this embodiment. Within the preset time period, acquire remote sensing images of the coastal wetland to be assessed at regular intervals. In this embodiment, the remote sensing images can be either multispectral or hyperspectral.

[0035] In this embodiment, the coastal wetlands to be evaluated may include mature coastal wetlands, i.e., wetlands that are not easily changed near the central areas of various types of coastal wetlands, and also include evolving coastal wetlands, such as the marginal areas of various types of coastal wetlands, which are areas that are more prone to change due to the influence of the environment, human activities, or biological invasions.

[0036] In this embodiment, coastal wetlands can include various types, such as salt marshes, mangroves, mudflats, and coastal seagrass beds. Hyperspectral image data and multispectral image data of the wetlands collected by satellite are obtained. For example, the hyperspectral image data can be acquired by a first satellite over multiple time periods, with a size of 1185×1342 pixels, 285 tunnels, and a spatial resolution of 30 meters. The multispectral image data can be acquired by a second satellite over the same time period, with a size of 3555×4026 pixels, 47 tunnels, and a selected spatial resolution of 10 meters.

[0037] In this embodiment, due to the differences in temporal and spatial resolutions between hyperspectral and multispectral image data, preprocessing is required. In this embodiment, geographic registration can be performed on the hyperspectral and multispectral image data. For example, spatial registration and atmospheric correction can be performed to compensate for the loss in classification caused by the temporal difference between the two image data. Due to the different resolutions and sizes of the hyperspectral and multispectral image data, upsampling is required. For example, the hyperspectral image data is upsampled by a factor of 3 to achieve the same size as the multispectral image data.

[0038] S20. Identify evolution data of different types of coastal wetlands in the remote sensing image set respectively, wherein the evolution data includes conversion data between different types of wetlands and net change data of each type of coastal wetland excluding the conversion data.

[0039] As an exemplary embodiment, a pre-trained classification network can be used for classification to obtain different types of coastal wetlands. In an exemplary embodiment, the classification network model can be implemented in Python and trained using real wetland remote sensing images. Of course, the use of other languages ​​to implement the classification network model is not limited in this embodiment. The specific training process includes: first, all parameters of the model are randomly initialized, and then the training data is input. After the data is pre-processed such as geographic information registration, it is input into the classification network model for forward propagation and the output is obtained; then, the loss of the model at this time is calculated using the constructed discriminant loss function and classification loss function respectively; the model parameters are updated through back propagation, and the accuracy of the current model is tested. In a certain number of training rounds, the model parameters are continuously updated through back propagation, and the model is saved each time the current best accuracy is broken through, so that the final trained network model can be obtained. In an optional embodiment, the training parameters are set as follows: the number of training rounds is 200, the learning rate is 0.005, and the stochastic gradient descent is used as the optimization function.

[0040] In this embodiment, after obtaining the coastal wetland type classification results of each remote sensing image, the scope and area of ​​each type of coastal wetland are determined, and the conversion areas between different types of wetlands and the net change areas of each type of coastal wetland excluding the conversion data are determined according to the time sequence of the remote sensing image set and the area data.

[0041] For example, 20 sets of remote sensing images are captured in time sequence, and the range and area of ​​salt marshes, mangroves, and mudflats in each remote sensing image are determined, and the changes in each type of wetland are determined in time sequence.

[0042] In one embodiment, the change may be classified into the type and area of ​​change from a non-coastal wetland to a certain type of coastal wetland or several types of coastal wetlands.

[0043] In another embodiment, the change may also be a change in type and area from one type of coastal wetland to another or several other types of coastal wetlands, for example, mudflats becoming salt marshes and / or mangroves, or mangroves and / or salt marshes becoming mudflats.

[0044] Net change data of the net change area within a preset time period is collected, illustratively including the wetland type and net change area of ​​the net change area, such as the area of ​​mangrove loss, the area of ​​mangrove gain, the area of ​​salt marsh loss, the area of ​​salt marsh gain, the area of ​​tidal flat loss, and the area of ​​tidal flat gain. In this embodiment, the change in the net change area may be due to environmental factors, human activities, or other factors. For example, the destruction of mangroves or salt marshes may lead to the partial loss of mangroves, or the artificial construction of mangroves or salt marshes may increase the number of mangroves or salt marshes, or the reclamation or landfill of tidal flats may lead to the loss of tidal flats.

[0045] Conversion data for conversion zones within a preset time period is collected. For example, the wetland type and area of ​​the conversion zone may be included. For example, sea level, temperature, or other climatic factors may cause mangroves or salt marshes to degrade and become mudflats. Another example is the invasion of mudflats by salt marsh or mangrove plants, resulting in a decrease in mudflat area and an increase in salt marsh or mangroves. Areas where coastal wetland types have changed are considered conversion zones.

[0046] In this embodiment, the change area and change type of the net change area and the conversion area and conversion type of the conversion area can be used as the evolution data of different types of coastal wetlands.

[0047] S30. Evaluate the carbon sequestration effect of the coastal wetland to be evaluated based on the conversion data and the net change data to obtain a carbon sequestration effect evaluation result.

[0048] In this embodiment, the net change area can be divided into an increase area and a decrease area. In this embodiment, the increase area and decrease area of ​​each wetland type can be counted separately. For each wetland type, when evaluating the carbon sequestration capacity, the carbon sequestration capacity of the coastal wetland type corresponding to the decrease area can be subtracted. For the increase in coastal wetlands, the carbon sequestration capacity of the increase in area can be obtained by multiplying the type of coastal wetland corresponding to the increase in area by the growth coefficient of the increase in coastal wetland (the growth coefficient gradually approaches 1 as the wetland in the increase in area matures). (Since the biological population of the newly created coastal wetland has not reached the level of mature coastal wetlands and is in a state of growth over time, the carbon sequestration capacity can gradually increase from the initial carbon sequestration capacity to the preset carbon sequestration capacity of the increased coastal wetland type over time.) The initial carbon sequestration capacity can be 40-60% of the preset carbon sequestration capacity, and the preset carbon sequestration capacity can be the carbon sequestration capacity of a mature coastal wetland of the corresponding type.

[0049] As for the carbon sink amount, since the original carbon sink amount in the reduced area will not change fundamentally in a short period of time, in this embodiment, the carbon sink amount in the reduced area can be counted and evaluated according to the original carbon sink amount. When evaluating the carbon sink amount in the increased area, since there is no blue carbon deposition before the increase, additional statistics can be performed according to the time of increase, and then the carbon sink effect evaluation results such as the carbon sink capacity and carbon sink amount of the net change area can be obtained.

[0050] As an exemplary embodiment, the conversion area is converted from one wetland type to another wetland type, and has carbon sequestration capacity and carbon sequestration amount before and after the conversion.

[0051] Different wetland types often have varying carbon sequestration capacities, amounts, and forms. For example, mangroves are coastal wetlands that are productive carbon sinks. The majority of their carbon sequestration comes from plant uptake, with some carbon coming from imported sources, such as particulate and dissolved organic carbon from the ocean brought in by tides, or from rivers. The average carbon accumulation rate for mangrove systems is 194 g / m² / year. Salt marshes are coastal wetlands that are productive carbon sinks. The majority of their carbon sequestration comes from plant uptake, with some carbon coming from imported sources, such as particulate and dissolved organic carbon from the ocean brought in by tides, or from rivers, or from mangrove exports. The average carbon accumulation rate for salt marshes is 164 g / m² / year. However, mudflats, with their own low biomass, have poor production capacity. Therefore, their primary carbon source is carbon imported from salt marshes, mangroves, or the ocean. The average carbon accumulation rate of the tidal flats is 140-160g / m2 / yr. Therefore, based on the different carbon sequestration capacities and sources of carbon sequestration of different types of coastal wetlands, the conversion area can be evaluated based on the type before and after conversion and the area of ​​the conversion area.

[0052] Since the conversion zone changes dynamically rather than suddenly, it is possible that the carbon sequestration forms and carbon sequestration capacities of coastal wetland types before and after conversion exist within the conversion zone. Therefore, in this embodiment, when evaluating the conversion zone, the area of ​​the conversion zone, the wetland types before and after conversion can be comprehensively considered to assess the carbon sequestration capacity and amount of the conversion zone, thereby accurately evaluating the carbon sequestration effect of the conversion zone.

[0053] In this embodiment, when evaluating the carbon sequestration effect of the coastal wetlands to be evaluated, especially when evaluating wetlands in areas with more frequent changes, in addition to the qualitative analysis of mature wetland areas in the existing technology, the evolution data of the coastal wetlands to be evaluated are also comprehensively considered, and factors characterizing the carbon sequestration effect such as the evolution type, the wetland type before and after the evolution, the carbon sequestration form before and after the evolution, the carbon sequestration capacity before and after the evolution, and the carbon sequestration amount before and after the evolution are considered to comprehensively evaluate the carbon sequestration effect of the coastal wetlands to be evaluated, so that the carbon sequestration effect of the wetlands to be evaluated can be obtained more accurately.

[0054] Furthermore, different types of coastal wetlands may experience a decrease or increase in their original carbon sink capacity before and after conversion. For example, when mudflats are converted to mangroves or salt marshes, their original input-based carbon sink capacity not only does not decrease, but the mangroves or salt marshes' barrier effect slows tidal currents, further increasing tidal carbon input from the ocean and boosting their carbon sink capacity. When mangroves or salt marshes are converted to mudflats, they gradually lose their productive capacity and become solely input-based carbon sinks. Without the barrier effect of the vegetation, tidal currents accelerate, accelerating carbon input to the ocean and causing some carbon loss into the ocean. Therefore, the carbon sink effect of a converted area cannot be assessed based on the current coastal wetland type. If the conversion is too rapid or over a large area, and if the changes in carbon sink form or capacity in the converted area due to wetland conversion are not considered, the overall carbon sink effect assessment is likely to be inaccurate.

[0055] Therefore, as shown in FIG2 , the carbon sequestration effect of the coastal wetland to be evaluated is evaluated based on the conversion data and the net change data to obtain the carbon sequestration effect evaluation result, including the following steps:

[0056] S31. Determine a net change assessment result based on the net change data and the type of coastal wetland that has undergone net change, wherein the net change data is the change in area of ​​non-coastal wetlands converted to coastal wetlands or coastal wetlands converted to non-coastal wetlands and the type of coastal wetlands that have undergone change;

[0057] S32. Determine the first type of the coastal wetland before the conversion and the second type of the coastal wetland after the conversion and the conversion area based on the conversion data.

[0058] S33 . Determine a conversion evaluation result based on the conversion area using a first weight coefficient corresponding to the first type and a second weight coefficient corresponding to the second type.

[0059] S34. The sum of the net change assessment results and the conversion assessment results shall be used as the carbon sink effect assessment result.

[0060] Regarding step S31, in this embodiment, the net change area can be divided into an increase area and a decrease area, wherein the increase area is the area where non-coastal wetlands change to coastal wetlands, and the decrease area is the area where coastal wetlands change to non-coastal wetlands.

[0061] In this embodiment, the area of ​​increase and decrease of each wetland type and the type of coastal wetland that has changed can be counted separately. For each wetland type, when evaluating the carbon sequestration capacity, the carbon sequestration capacity of the type of coastal wetland corresponding to the decreased area can be subtracted; the carbon sequestration capacity of the increased area can be obtained by multiplying the type of coastal wetland corresponding to the increased area by the growth coefficient (as the wetland in the increased area matures, the growth coefficient gradually approaches 1). (Since the biological population of the newly created coastal wetland has not reached the level of mature coastal examples and is growing over time, the carbon sequestration capacity can gradually increase from the initial carbon sequestration capacity to the preset carbon sequestration capacity over time). The initial carbon sequestration capacity can be 40-60% of the preset carbon sequestration capacity, and the preset carbon sequestration capacity can be the carbon sequestration capacity of a mature coastal wetland of the corresponding type.

[0062] For step S32 and step S33, after identifying the type of coastal wetland in time sequence, a before-after comparison is performed in time sequence to obtain the conversion data of the coastal wetland type in the preset time period, for example, the wetland type before and after the conversion, the area of ​​the conversion area that undergoes conversion in the preset time period, and other data.

[0063] Since the original carbon sequestration forms of different types of coastal wetlands may disappear or increase before and after conversion, the conversions between different types have different weights when evaluating the carbon sequestration effects.

[0064] In this embodiment, the first type of coastal wetland before the conversion corresponds to the first weight coefficient; the second type of coastal wetland after the conversion corresponds to the second weight coefficient. In this embodiment, different types before the conversion correspond to different weight coefficients, and different types after the conversion correspond to different weight coefficients.

[0065] For example, consider a case where the first type of wetland includes mangroves and / or salt marshes, and the second type of wetland includes tidal flats. The conversion area consists of mangroves and / or salt marshes being converted to tidal flats. Prior to conversion, the mangroves and / or salt marshes primarily produced carbon through plant production. During the conversion process, their carbon production capacity gradually declines, while the carbon input can remain unchanged or decrease. Therefore, the conversion area retains both the carbon sequestration capacity of the first type prior to conversion and the carbon sequestration capacity of the second type after conversion. When evaluating carbon sequestration effectiveness, the conversion evaluation result can be determined for the conversion area based on the conversion area using a first weighting factor corresponding to the first type and a second weighting factor corresponding to the second type. For example, the carbon sequestration capacity of the first type of coastal wetland is A, and the carbon sequestration capacity of the second type of coastal wetland is B. Since the conversion area is an immature coastal wetland, the carbon sequestration capacity of the conversion area is assessed by multiplying A by the first weighting factor to obtain the carbon sequestration capacity of the first type during conversion, and multiplying B by the second weighting factor to obtain the carbon sequestration capacity of the second type during conversion. The sum of the first and second carbon sequestration capacities is used as the carbon sequestration evaluation result for the conversion area.

[0066] As an exemplary embodiment, the identification of the conversion area is obtained by classifying remote sensing images, usually based on the significant features of a certain type of wetland. The features of the conversion area may not be particularly obvious. Therefore, the recognition probability can be used to determine the conversion degree of the current conversion area. For example, the conversion of salt marsh to tidal flat is that as the salt marsh plants degenerate, the salt marsh plant characteristics gradually weaken and the tidal flat characteristics gradually strengthen. The degradation may be a relatively slow process. Therefore, there are salt marsh plant characteristics and tidal flat characteristics in the conversion area. The recognition probability can be used to characterize the number of salt marsh plants, and then characterize the degree of salt marsh degradation or the degree of conversion of the tidal flat.

[0067] In this embodiment, the first type of wetland includes mangroves and / or salt marshes; the second type of wetland includes tidal flats. Specifically, the conversion of salt marshes or mangroves to tidal flats is used as an example for description:

[0068] The first weight coefficient is a1, where a1 is the identification probability that the conversion area of ​​the coastal wetland is mangroves and / or salt marshes; the second weight coefficient is b1, where b1 is the identification probability that the conversion area of ​​the coastal wetland is a mudflat, and the sum of a1 and b1 is less than or equal to 1.

[0069] Determining the conversion evaluation result based on the conversion area by using a first weight coefficient corresponding to the first type and a second weight coefficient corresponding to the second type includes:

[0070] The product of the preset carbon sequestration capacity of the mangroves and / or salt marshes in the conversion area and the first weight coefficient is used as a first evaluation result in the wetland conversion process;

[0071] The product of the preset carbon sequestration capacity of the tidal flat under the conversion area and the second weight coefficient is used as the second evaluation result in the wetland conversion process;

[0072] The sum of the first evaluation result and the second evaluation result is used as the conversion evaluation result.

[0073] As an exemplary embodiment, during the conversion of mangroves or salt marshes to tidal flats, their production capacity gradually decreases, gradually becoming an input-type carbon sink. Therefore, when evaluating carbon sink effectiveness, the preset (original) carbon sink capacity can be multiplied by the corresponding identification probability (weight) to obtain the carbon sink capacity of the types included in the conversion area (types before and after conversion). The carbon sink capacity of the conversion area can be the product of the carbon sink capacity A of the first type of coastal wetland and the first weight coefficient a1, and the carbon sink capacity B of the second type of coastal wetland and the second weight coefficient b1.

[0074] As another optional embodiment, the first type of wetland includes mudflats; the second type of wetland includes salt marshes or mangroves. Specifically, the conversion of mudflats into salt marshes or mangroves is used as an example for explanation:

[0075] The conversion of mudflats to salt marshes or mangroves not only increases their productivity but also their sedimentation efficiency. For example, the conversion of mudflats to salt marshes, where Spartina alterniflora is present, not only increases plant biomass and organic litter input, but its dense vegetation also slows water flow, accelerating sediment accumulation and increasing the sedimentation rate.

[0076] During the conversion of tidal flats to salt marshes or mangroves, vegetation increases and new vegetation branches and leaves will be added to the soil. Therefore, the sedimentation capacity will increase while the sedimentation capacity of the original tidal flats remains unchanged. Therefore, the first weight coefficient is 1+b2, where b2 is the identification probability that the conversion area of ​​the coastal wetland is a tidal flat; during the conversion of tidal flats to salt marshes or mangroves, the production capacity changes from almost none to gradually increasing. Therefore, the second weight coefficient is a2, where a2 is the identification probability that the conversion area of ​​the coastal wetland is a mangrove and / or salt marsh, and the sum of a2 and b2 is less than or equal to 1.

[0077] Determining the conversion evaluation result based on the conversion area by using a first weight coefficient corresponding to the first type and a second weight coefficient corresponding to the second type includes:

[0078] The product of the preset carbon sequestration capacity of the tidal flat under the conversion area and the first weight coefficient is used as the third evaluation result in the wetland conversion process;

[0079] The product of the preset carbon sequestration capacity of the mangroves and / or salt marshes in the conversion area and the second weight coefficient is used as the fourth assessment result in the wetland conversion process;

[0080] The sum of the third evaluation result and the fourth evaluation result is used as the conversion evaluation result.

[0081] By comprehensively considering various situations during the conversion process, a more accurate assessment of the carbon sequestration effect in the conversion area can be made.

[0082] In an alternative embodiment, to further accurately assess the carbon sequestration effect of the conversion area, during the conversion of mudflats to salt marshes or mangroves, dense vegetation can slow water flow, accelerate sediment accumulation, and increase the deposition rate. Therefore, c times 1 + b2, where c is the deposition efficiency multiplier and c is greater than 1. In this embodiment, c can gradually increase with the increase in vegetation in the conversion area. In this embodiment, c can also be positively correlated with the second type of identification probability, that is, c is positively correlated with the identification probability of salt marshes or mangroves.

[0083] As an exemplary embodiment, in the process of converting from the first type to the second type, as time goes by, it gets closer and closer to the second type. Therefore, the first weight coefficient and the second weight coefficient are adjusted based on the duration of the conversion, wherein the longer the time for the conversion to occur, the smaller the first weight coefficient, and the larger the second weight coefficient.

[0084] As an exemplary embodiment, when evaluating the carbon sequestration effect of coastal wetlands in an assessment area, the carbon sequestration effect is calculated as the sum of the net change area carbon sequestration effect assessment results, the transition area carbon sequestration effect assessment results, and the mature area carbon sequestration effect assessment results. In this embodiment, carbon sequestration effects, such as carbon sequestration amount and carbon sequestration capacity, are also affected by the environment. Therefore, different types of coastal wetland areas are identified in the remote sensing image collection; environmental information within the preset time period is obtained; and the carbon sequestration effect assessment results are adjusted based on this environmental information.

[0085] Exemplarily, the environmental information includes temperature information; and adjusting the carbon sink effectiveness assessment result based on the environmental information includes: determining an organic carbon decomposition coefficient based on the temperature information; and adjusting the carbon sink effectiveness assessment result based on the decomposition coefficient. Rising average temperatures accelerate the decomposition rate of organic carbon, particularly for tidal flats, which primarily serve as input-based carbon sinks. Therefore, in this embodiment, the carbon sink effectiveness needs to be adjusted based on temperature information.

[0086] Furthermore, when assessing carbon sequestration effectiveness in deciduous latitudes, it's also necessary to consider whether plants are germinating and growing smoothly. In spring, when plants are in the budding stage, excessive rainfall can hinder germination and, in turn, reduce plant productivity. Therefore, it's also necessary to obtain the amount of spring rainfall and determine an organic carbon generation coefficient based on this amount. The carbon sequestration effectiveness assessment results are then adjusted based on this organic carbon generation coefficient. In this embodiment, the organic carbon generation coefficient can be obtained based on experience or experimentation.

[0087] As another optional embodiment, the coastal wetland also includes seagrass beds. Therefore, the transparency of the coastal waters also needs to be identified. In this embodiment, remote sensing images can be used to identify the transparency of the coastal waters. The higher the transparency, the stronger the carbon fixation capacity of the seagrass beds and the higher the carbon sink effect. Therefore, the transparency of the seawater in a preset time period can be identified based on remote sensing images to obtain the average transparency. Based on the average transparency, the preset carbon sink capacity of the seagrass beds can be adjusted to obtain the carbon sink effect evaluation results of the seagrass beds.

[0088] As an exemplary embodiment, after obtaining remote sensing images of coastal wetlands within a preset time period, the evolution data of coastal wetlands to be assessed in the future can be predicted based on the evolution data within the preset time period. Predetermined evolution data can then be obtained, and predictions can be made for the coastal wetlands to be assessed based on the predicted evolution data. This can then provide targeted improvements, for example, preventing the reduction of carbon sequestration capacity.

[0089] As another optional embodiment, the organic carbon types and the organic carbon content of each type in the soil samples of the coastal wetland to be evaluated are obtained, and the organic carbon types include production-type organic carbon and input-type organic carbon; and the carbon sink amount within the preset time period is determined based on the changes in production-type organic carbon and input-type organic carbon within the preset time period.

[0090] In this example, soil profiles were excavated and plant biomass was collected at the designed sampling points. Each profile was excavated to a depth of 1 meter, and soil samples were collected at regular intervals of 0-10 cm, 10-20 cm, 20-30 cm, and 30-40 cm. Field work included investigations of the geographical location of the soil profile and the soil-forming environment (topography, climate, vegetation, etc.).

[0091] An embodiment of the present application also provides a coastal wetland carbon sequestration effect evaluation system, as shown in Figure 3, including: an acquisition module 10, used to obtain a remote sensing image set of the coastal wetland to be evaluated within a preset time period; an identification module 20, used to respectively identify the evolution data of different types of coastal wetlands in the remote sensing image set, the evolution data including conversion data between different types of wetlands and net change data of each type of coastal wetland excluding the conversion data; an evaluation module 30, used to evaluate the carbon sequestration effect of the coastal wetland to be evaluated based on the conversion data and the net change data, and obtain a carbon sequestration effect evaluation result; wherein the carbon sequestration form and carbon sequestration effect of the coastal wetland corresponding to the conversion data are different from the carbon sequestration form and carbon sequestration effect of the coastal wetland corresponding to the net change data.

[0092] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0093] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0094] In addition, all functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0095] Those skilled in the art will appreciate that all or part of the steps of the above-mentioned method embodiments may be implemented by hardware associated with program instructions, and the aforementioned program may be stored in a computer-readable storage medium. When the program is executed, the program executes the steps of the above-mentioned method embodiments. The aforementioned storage medium includes various media that can store program codes, such as mobile storage devices, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0096] Alternatively, if the above-mentioned integrated unit of the present invention is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, magnetic disks or optical disks.

[0097] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for evaluating the carbon sink effect of coastal wetlands, characterized in that: include: Obtain a set of remote sensing images of the coastal wetland to be assessed within a preset time period; Respectively identifying the evolution data of different types of coastal wetlands in the remote sensing image set, wherein the evolution data includes conversion data between different types of wetlands and net change data of each type of coastal wetland except the conversion data; The carbon sink effect of the coastal wetland to be evaluated is evaluated based on the conversion data and the net change data to obtain a carbon sink effect evaluation result; wherein the carbon sink form and carbon sink effect of the coastal wetland corresponding to the conversion data are different from the carbon sink form and carbon sink effect of the coastal wetland corresponding to the net change data.

2. The coastal wetland carbon sink effect assessment method according to claim 1, characterized in that: The evolution data of respectively identifying different types of coastal wetlands in the remote sensing image set includes: Respectively identifying the types of coastal wetlands in the remote sensing image set; Determining area data of each type of coastal wetlands to be assessed in each remote sensing image based on the identified types of coastal wetlands; Determine the conversion area between different types of wetlands and the net change area of ​​each type of coastal wetland excluding the conversion data according to the time sequence of the remote sensing image set and the area data; The conversion data of the conversion area and the net change data of the net change area are used as the evolution data.

3. The coastal wetland carbon sink effect assessment method according to claim 2, characterized in that: The carbon sink effect of the coastal wetland to be evaluated is evaluated based on the conversion data and the net change data to obtain a carbon sink effect evaluation result, which includes: Determine a net change assessment result based on the net change data and the type of coastal wetland that has undergone a net change, wherein the net change data is the change in area from non-coastal wetlands to coastal wetlands or from coastal wetlands to non-coastal wetlands and the type of coastal wetlands that have undergone a net change; Determine, based on the conversion data, a first type of the coastal wetland before the conversion and a second type of the coastal wetland after the conversion and a conversion area; Determine a conversion evaluation result based on the conversion area using a first weight coefficient corresponding to the first type and a second weight coefficient corresponding to the second type; The sum of the net change assessment results and the conversion assessment results is taken as the carbon sink effect assessment result.

4. The coastal wetland carbon sink effect assessment method according to claim 3, characterized in that: The first type of wetland includes mangroves and / or salt marshes; the second type of wetland includes tidal flats; The first weight coefficient is a1, where a1 is the recognition probability that the conversion area of ​​the coastal wetland is a mangrove and / or a salt marsh; The second weight coefficient is b1, where b1 is the recognition probability that the conversion area of ​​the coastal wetland is a tidal flat, where the sum of a1 and b1 is less than or equal to 1; The determining of the conversion evaluation result based on the conversion area by using a first weight coefficient corresponding to the first type and a second weight coefficient corresponding to the second type comprises: The product of the preset carbon sink capacity of the mangroves and / or salt marshes in the conversion area and the first weight coefficient is used as the first evaluation result in the wetland conversion process; The product of the preset carbon sink capacity of the tidal flat under the conversion area and the second weight coefficient is used as the second evaluation result in the wetland conversion process; The sum of the first evaluation result and the second evaluation result is used as the conversion evaluation result.

5. The coastal wetland carbon sink effect assessment method according to claim 3, characterized in that: The first type of wetland includes tidal flats; the second type of wetland includes mangroves and / or salt marshes; The first weight coefficient is 1+b2, wherein b2 is the recognition probability that the conversion area of ​​the coastal wetland is a tidal flat; The second weight coefficient is a2, where a2 is the recognition probability that the conversion area of ​​the coastal wetland is a mangrove and / or a salt marsh, where the sum of a2 and b2 is less than or equal to 1; The product of the preset carbon sink capacity of the tidal flat under the conversion area and the first weight coefficient is used as the third evaluation result in the wetland conversion process; The product of the preset carbon sink capacity of the mangroves and / or salt marshes under the conversion area and the second weight coefficient is used as the fourth evaluation result in the wetland conversion process; The sum of the third evaluation result and the fourth evaluation result is used as the conversion evaluation result.

6. The coastal wetland carbon sink effect assessment method according to claim 5, characterized in that: The first weight coefficient is c times 1+b2, where c is the deposition efficiency increase factor, and c is greater than 1.

7. The coastal wetland carbon sink effect assessment method according to claim 4, characterized in that: The first weight coefficient and the second weight coefficient are adjusted based on the duration of the conversion, wherein the longer the duration of the distance conversion occurs, the smaller the first weight coefficient is, and the larger the second weight coefficient is.

8. The coastal wetland carbon sink effect assessment method according to claim 1, characterized in that: Also includes: Respectively identifying different types of coastal wetland areas in the remote sensing image set; Acquiring environmental information within the preset time period; The carbon sink effect assessment result is adjusted based on the environmental information.

9. The coastal wetland carbon sink effect assessment method according to claim 8, characterized in that: The environmental information includes temperature information; The adjusting the carbon sink effect assessment result based on the environmental information includes: determining an organic carbon decomposition coefficient based on the temperature information; Adjusting the carbon sink effect assessment result based on the decomposition coefficient; and / or, The environmental information includes the amount of spring rainfall; determining an organic carbon generation coefficient based on the spring rainfall amount; The carbon sink effect evaluation result is adjusted based on the organic carbon generation coefficient.

10. A coastal wetland carbon sink effect assessment system, characterized in that: include: An acquisition module, used for acquiring a remote sensing image set of a coastal wetland to be evaluated within a preset time period; An identification module, used to respectively identify the evolution data of different types of coastal wetlands in the remote sensing image set, wherein the evolution data includes conversion data between different types of wetlands and net change data of each type of coastal wetland except the conversion data; An evaluation module is used to evaluate the carbon sink effect of the coastal wetland to be evaluated based on the conversion data and the net change data to obtain a carbon sink effect evaluation result; wherein the carbon sink form and carbon sink effect of the coastal wetland corresponding to the conversion data are different from the carbon sink form and carbon sink effect of the coastal wetland corresponding to the net change data.

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