A method and system for determining total primary productivity of a terrestrial ecosystem

Abstract

The application provides a land ecosystem gross primary productivity determination method and system, and the method comprises the following steps: collecting historical eco-hydro-meteorological data and measured values of land ecosystem gross primary productivity in a research area; constructing a generalized water-energy complementary gross primary productivity model, wherein the generalized water-energy complementary gross primary productivity model comprises a comprehensive coordination index, an energy limitation correction parameter and an available water amount correction parameter, the water amount limitation reference productivity and the energy limitation reference productivity are nonlinearly coupled by the comprehensive coordination index, the energy limitation correction parameter and the available water amount correction parameter; calibrating the comprehensive coordination index, the energy limitation correction parameter and the available water amount correction parameter; inputting the to-be-calculated eco-hydro-meteorological data into the generalized water-energy complementary gross primary productivity model after parameter calibration, and obtaining the target land ecosystem gross primary productivity. The application improves the estimation accuracy of the gross primary productivity.

Description

Technical Field

[0001] This invention relates to the field of ecosystem carbon cycle simulation and quantitative estimation of terrestrial vegetation productivity, specifically to a method and system for determining the total primary productivity of terrestrial ecosystems. Background Technology

[0002] Gross primary productivity (GMP) of terrestrial ecosystems is a key indicator characterizing the intensity of vegetation photosynthesis and terrestrial carbon sequestration capacity, playing a crucial role in global carbon cycle research, climate change assessment, and ecosystem service function analysis. Accurate simulation of GMP is one of the core issues in current land surface process modeling and ecosystem modeling research.

[0003] Existing methods for estimating gross primary productivity (GMP) mainly include empirical statistical models, light energy use efficiency (SEE) models, physiological process models, and semi-empirical models based on flux observations. Among these, SEE models have been widely used in regional and global-scale studies due to their simple structure and high computational efficiency. These models are typically based on the linear relationship between absorbed photosynthetically active radiation (EPA) and fixed SEE, with adjustments made by introducing stress factors such as temperature and water. However, existing models generally suffer from the following problems: first, water and energy constraints are often treated separately, lacking a unified physical mechanism to characterize their synergistic limitation of carbon assimilation; second, model parameters largely rely on empirical settings, resulting in insufficient spatial transferability and physical interpretability. These two issues lead to insufficient accuracy in the constructed GMP models, consequently resulting in low accuracy in the determined GMP of terrestrial ecosystems.

[0004] Therefore, there is an urgent need for a method and system for determining the total primary productivity of terrestrial ecosystems, which can synergistically handle water and energy constraints and overcome the technical problem of inaccurate estimation of total primary productivity of terrestrial ecosystems caused by setting model parameters based on experience. Summary of the Invention

[0005] In view of this, it is necessary to provide a method and system for determining the total primary productivity of terrestrial ecosystems, in order to solve the technical problems of the separate treatment of water and energy constraints in the existing technology, and the inaccurate estimation of the total primary productivity of terrestrial ecosystems caused by the empirical setting of model parameters.

[0006] To address the aforementioned technical problems, in a first aspect, the present invention provides a method for determining the total primary productivity of a terrestrial ecosystem, comprising: Historical eco-hydrological and meteorological data of the study area and the measured values ​​of total primary productivity of terrestrial ecosystems corresponding to the historical eco-hydrological and meteorological data were collected. A generalized hydropower complementary total primary productivity model is constructed, comprising a comprehensive coordination index reflecting the ecosystem's baseline productivity of total primary productivity under hydropower constraints, an energy constraint correction parameter for correcting the calculation of effective radiation absorbed by plant photosynthesis and the conversion error of the baseline productivity of total primary productivity, and an available water quantity correction parameter for correcting the available water quantity under the influence of climate conditions and human activities. The generalized hydropower complementary total primary productivity model nonlinearly and complementaryly couples the water quantity constraint baseline productivity with the energy constraint baseline productivity through the comprehensive coordination index, the energy constraint correction parameter, and the available water quantity correction parameter. The historical eco-hydrological and meteorological data are input into the generalized hydropower complementary total primary productivity model to obtain the predicted value of the total primary productivity of the terrestrial ecosystem. Based on the measured value of the total primary productivity of the terrestrial ecosystem, and with the optimization of the preset objective function as the goal, the comprehensive coordination index, the energy limitation correction parameter, and the available water correction parameter are calibrated. Obtain the eco-hydrological and meteorological data to be calculated for the study area, and input the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration to obtain the total primary productivity of the target terrestrial ecosystem.

[0007] In one possible implementation, the generalized hydropower complementary total primary productivity model is as follows: ; In the formula, GPP is the predicted total primary productivity of terrestrial ecosystems; G(LUE) is the energy baseline productivity; G(W+I) is the water baseline productivity; n is the integrated coordination index; b is the energy constraint correction parameter; and I is the available water correction parameter.

[0008] In one possible implementation, the value range of the integrated coordination index is 0.1 to 5, the value range of the energy limitation correction parameter is 0 to 1, and the value range of the available water correction parameter is -50 to 50.

[0009] In one possible implementation, the energy baseline productivity is: ; In the formula, APAR represents the absorbed photosynthetically active radiation; ε FRAR is the photosynthetically active radiation ratio; PAR is the solar effective radiation ratio. Temperature stress factor; VPD is the regional saturated vapor pressure difference stress factor; VPD is the regional saturated vapor pressure difference. The maximum regional saturated vapor pressure difference for plants to perform photosynthesis; The minimum saturated vapor pressure difference required for plants to perform photosynthesis; The minimum threshold temperature for plants to perform photosynthesis; The maximum threshold for the minimum temperature at which plants can perform photosynthesis.

[0010] In one possible implementation, the water-based productivity is: ; In the formula, W represents net effective moisture; θ max ΔS represents the maximum water use efficiency; P represents the total effective water consumption; ΔS represents the change in soil moisture content; and ΔSnow represents the change in snow depth equivalent.

[0011] In one possible implementation, the preset objective function is the Nash efficiency coefficient, which is: ; In the formula, NSE is the Nash efficiency coefficient. Let be the predicted total primary productivity of the terrestrial ecosystem at time i; Let be the measured value of total primary productivity of the terrestrial ecosystem at time i; m is the number of simulated months. This represents the average of the measured values ​​of total primary productivity of terrestrial ecosystems.

[0012] In one possible implementation, the optimization algorithm used for the calibration of the integrated coordination index, the energy limitation correction parameter, and the available water correction parameter is the SCE-UA optimization algorithm.

[0013] In one possible implementation, before obtaining the total primary productivity of the target terrestrial ecosystem in the generalized hydropower complementary total primary productivity model after inputting the eco-hydrological and meteorological data to be calculated into the parameter calibrated model, the method further includes: Input the historical eco-hydrological and meteorological data into at least one existing gross primary productivity prediction model to obtain at least one existing gross primary productivity prediction value; Based on the at least one existing total primary productivity (TPP) prediction value, the terrestrial ecosystem TPP prediction value, the terrestrial ecosystem TPP measured value, and the preset evaluation index, determine whether the prediction accuracy of the generalized hydropower complementary TPP model is better than that of the existing TPP prediction model. The total primary productivity of the target terrestrial ecosystem is obtained from the generalized hydropower complementary total primary productivity model after the input parameters of the eco-hydrological and meteorological data to be calculated are calibrated, including: When the prediction accuracy of the generalized hydropower complementary total primary productivity model is better than that of the existing total primary productivity prediction model, the target terrestrial ecosystem total primary productivity is obtained by inputting the eco-hydrological and meteorological data to be calculated into the parameter-calibrated generalized hydropower complementary total primary productivity model.

[0014] In one possible implementation, the preset evaluation index includes at least one of the following: Nash efficiency coefficient, Kling-Gupta efficiency coefficient, root mean square error, and coefficient of determination.

[0015] Secondly, the present invention also provides a system for determining the total primary productivity of a terrestrial ecosystem, comprising: The historical data acquisition unit is used to collect historical eco-hydrological and meteorological data of the study area and the measured values ​​of total primary productivity of the terrestrial ecosystem corresponding to the historical eco-hydrological and meteorological data. The model building unit is used to construct a generalized hydropower complementary total primary productivity model. This model includes a comprehensive coordination index reflecting the ecosystem's response to the baseline productivity of total primary productivity under hydropower constraints, an energy constraint correction parameter for correcting the calculation of effective radiation absorbed by plant photosynthesis and the conversion error of the baseline productivity, and an available water quantity correction parameter for correcting the available water quantity under the influence of climate conditions and human activities. The generalized hydropower complementary total primary productivity model nonlinearly and complementaryly couples the water quantity constraint baseline productivity with the energy constraint baseline productivity through the comprehensive coordination index, the energy constraint correction parameter, and the available water quantity correction parameter. The model parameter calibration unit is used to input the historical eco-hydrological and meteorological data into the generalized hydropower complementary total primary productivity model to obtain the predicted value of the total primary productivity of the terrestrial ecosystem. Based on the measured value of the total primary productivity of the terrestrial ecosystem, and with the optimization of the preset objective function as the objective, the comprehensive coordination index, the energy limitation correction parameter, and the available water correction parameter are calibrated. The GPP determination unit is used to acquire the eco-hydrological and meteorological data to be calculated in the study area, and input the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration to obtain the total primary productivity of the target terrestrial ecosystem.

[0016] The beneficial effects of this invention are as follows: The method for determining the total primary productivity (TPP) of terrestrial ecosystems provided by this invention includes a comprehensive coordination index in the generalized hydropower-complementary TTP model to reflect the baseline productivity of TTP under hydropower constraints. This comprehensive coordination index quantitatively characterizes the nonlinear complementary coupling relationship between the baseline productivity constrained by water and energy. This index directly reflects the ecosystem's ability to coordinately regulate limiting factors under different hydropower supply conditions, achieving coordinated handling of water and energy constraints. It overcomes the shortcomings of traditional models that treat the two separately and lack a unified physical mechanism, thus significantly improving the accuracy of TTP estimation. Simultaneously, by including energy constraint correction parameters in the generalized hydropower-complementary TTP model, it compensates for the shortcomings of empirically setting light energy utilization efficiency in traditional light energy utilization models. Through adaptive adjustment via calibration, it avoids systematic biases caused by differences in vegetation type, radiation data errors, and other factors, thereby improving the estimation accuracy of energy-constrained baseline productivity. By setting the generalized hydropower complementary total primary productivity model to include available water quantity correction parameters, the model can adapt to human disturbances, expand the model's application capability under non-natural hydrological conditions, and avoid the deviation in total primary productivity estimation caused by inaccurate estimation of available water quantity.

[0017] Furthermore, the parameter calibration in the generalized hydropower complementary total primary productivity model constructed in this invention is performed with the goal of optimizing the preset objective function, which avoids the uncertainty caused by the traditional model's reliance on empirical parameter setting, and improves the spatial portability of the model under different climate regions and vegetation types and the reliability of the estimation results.

[0018] Furthermore, the generalized hydropower complementary total primary productivity model constructed in this invention requires only comprehensive coordination indicators, energy constraint correction parameters, and available water quantity correction parameters for demand calibration. With fewer parameters required for demand calibration, it has high computational efficiency and can be directly driven by remote sensing or reanalysis data. It is suitable for rapid calculations at the station scale, watershed scale, and global grid scale, effectively solving the technical problem of existing methods that are difficult to balance between estimation accuracy and computational efficiency. This improves the practicality and engineering feasibility of the model in large-scale simulations, long-term sequence analysis, and multi-scenario applications. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1A schematic flowchart of an embodiment of the method for determining the total primary productivity of a terrestrial ecosystem provided by the present invention; Figure 2 This is a schematic flowchart of an embodiment of the verification of the generalized hydropower complementary total primary productivity model provided by the present invention. Figure 3 This is a schematic diagram of an embodiment of the system for determining the total primary productivity of terrestrial ecosystems provided by the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] It should be understood that the illustrative drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the invention. It should be understood that the operations in the flowcharts may be implemented out of order, and steps without logical contextual relationships may be reversed or performed simultaneously. Furthermore, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor systems and / or microcontroller systems.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] This invention provides a method and system for determining the total primary productivity of a terrestrial ecosystem, which will be described below.

[0025] Figure 1 A schematic flowchart of an embodiment of the method for determining the total primary productivity of a terrestrial ecosystem provided by the present invention is shown below. Figure 1 As shown, methods for determining the total primary productivity of terrestrial ecosystems include: S101. Collect historical eco-hydrological and meteorological data of the study area and the measured values ​​of total primary productivity of terrestrial ecosystems corresponding to the historical eco-hydrological and meteorological data.

[0026] Historical eco-hydrological and meteorological data includes raw data that can be directly collected and analytical data obtained after calculation and analysis based on the raw data.

[0027] It should be understood that the specific raw data and analysis data need to be determined based on the parameters required for the subsequent construction of the generalized hydropower complementary total primary productivity model.

[0028] S102. Construct a generalized hydropower complementary total primary productivity model. The generalized hydropower complementary total primary productivity model includes a comprehensive coordination index to reflect the ecosystem's total primary productivity baseline productivity under hydropower constraints, an energy constraint correction parameter to correct the calculation of effective radiation absorbed by plant photosynthesis and the conversion error of the total primary productivity baseline productivity, and an available water quantity correction parameter to correct the available water quantity under the influence of climate conditions and human activities. The generalized hydropower complementary total primary productivity model nonlinearly and complementaryly couples the water quantity constraint baseline productivity with the energy constraint baseline productivity through the comprehensive coordination index, the energy constraint correction parameter, and the available water quantity correction parameter. S103. Input historical eco-hydrological and meteorological data into the generalized hydropower complementary total primary productivity model to obtain the predicted value of total primary productivity of terrestrial ecosystem. Based on the measured value of total primary productivity of terrestrial ecosystem, and with the goal of optimizing the preset objective function, calibrate the comprehensive coordination index, energy limitation correction parameter and available water correction parameter. S104. Obtain the eco-hydrological and meteorological data to be calculated for the study area, and input the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration to obtain the total primary productivity of the target terrestrial ecosystem.

[0029] It should be understood that the method for determining the total primary productivity of terrestrial ecosystems in this embodiment of the invention can be implemented in any device based on the method for determining the total primary productivity of terrestrial ecosystems, such as a vegetation productivity estimation device. Specifically, the method for determining the total primary productivity of terrestrial ecosystems is stored in the aforementioned device as a pre-programmed procedure. When the device is started, the procedure is invoked, and the method for determining the total primary productivity of terrestrial ecosystems is implemented.

[0030] Compared with existing technologies, the method for determining the total primary productivity of terrestrial ecosystems provided in this invention establishes a generalized hydropower-complementary total primary productivity model, including a comprehensive coordination index that reflects the ecosystem's baseline productivity of total primary productivity under hydropower constraints. This comprehensive coordination index quantitatively characterizes the nonlinear complementary coupling relationship between the water-constrained baseline productivity and the energy-constrained baseline productivity. This index directly reflects the ecosystem's ability to coordinately regulate limiting factors under different hydropower supply conditions, achieving coordinated handling of water and energy constraints. It overcomes the shortcomings of traditional models that treat the two separately and lack a unified physical mechanism, thus significantly improving the accuracy of total primary productivity estimation. Simultaneously, by including energy constraint correction parameters in the generalized hydropower-complementary total primary productivity model, it compensates for the shortcomings of empirically setting light energy utilization efficiency in traditional light energy utilization efficiency models. Through adaptive adjustment via calibration, it avoids systematic biases caused by differences in vegetation type, radiation data errors, and other factors, improving the estimation accuracy of energy-constrained baseline productivity. By setting the generalized hydropower complementary total primary productivity model to include available water quantity correction parameters, the model can adapt to human disturbances, expand the model's application capability under non-natural hydrological conditions, and avoid the deviation in total primary productivity estimation caused by inaccurate estimation of available water quantity.

[0031] Furthermore, the parameter calibration in the generalized hydropower complementary total primary productivity model constructed in this embodiment of the invention is performed with the goal of optimizing the preset objective function, which avoids the uncertainty caused by the traditional model's reliance on empirical parameter setting, and improves the spatial portability of the model under different climate regions and vegetation types and the reliability of the estimation results.

[0032] Furthermore, the generalized hydropower complementary total primary productivity model constructed in this embodiment of the invention requires only comprehensive coordination indicators, energy constraint correction parameters, and available water quantity correction parameters for demand calibration. With fewer parameters required for demand calibration, the computational efficiency is high. It can be directly driven by remote sensing or reanalysis data and is suitable for rapid calculation at the station scale, watershed scale, and global grid scale. It effectively solves the technical problem of existing methods that are difficult to balance between estimation accuracy and computational efficiency, and improves the practicality and engineering feasibility of the model in large-scale simulation, long-term sequence analysis, and multi-scenario applications.

[0033] In a specific embodiment of the present invention, the generalized hydropower complementary total primary productivity model is as follows: ; In the formula, GPP is the predicted total primary productivity of terrestrial ecosystems; G(LUE) is the energy baseline productivity, which is considered to be the GPP baseline productivity under energy limitation control for photosynthesis in terrestrial ecosystems; G(W+I) is the water baseline productivity, which is considered to be the GPP baseline productivity under water limitation control for photosynthesis in terrestrial ecosystems; n is the comprehensive coordination index; b is the energy limitation correction parameter; and I is the available water correction parameter.

[0034] In a specific embodiment of the present invention, the energy baseline productivity is: ; In the formula, APAR represents the absorbed photosynthetically active radiation; ε FRAR is the photosynthetically active radiation ratio; PAR is the solar effective radiation ratio. Temperature stress factor; VPD is the regional saturated vapor pressure difference stress factor; VPD is the regional saturated vapor pressure difference. The maximum regional saturated vapor pressure difference for plants to perform photosynthesis; The minimum saturated vapor pressure difference required for plants to perform photosynthesis; The minimum threshold temperature for plants to perform photosynthesis; The maximum threshold for the minimum temperature at which plants can perform photosynthesis.

[0035] In a specific embodiment of the present invention, the water quantity baseline productivity is: ; In the formula, W represents net effective moisture; θ max P represents the maximum water use efficiency; P represents the total effective water consumption; △ S This represents the change in soil moisture content; △ Snow This represents the change in snow depth equivalent.

[0036] It should be noted that the construction process of the generalized hydropower complementary total primary productivity model is as follows: From the generalized proportionality assumption equation, we can obtain: (1) In the formula, H P Total available water volume; H E For energy supply. H / H E Y / H represents the proportion of actual energy supplied to total energy. P This indicates the proportion of the total water volume that has not been converted into H. When the two are equal, it means that the degree of energy limitation and the degree of water underutilization are synchronized.

[0037] A certain amount of water H in the watershed P Divided into H and Y, the hydrological variable H is also affected by HE Given the constraints, we have: (2) This expression establishes a symmetrical and complementary relationship between water and energy constraints.

[0038] From the hydropower coupling equation, we can obtain: (3) Wherein, n is a comprehensive coordination index reflecting the sensitivity and regulation capacity of hydrological variables to hydropower constraints. Equation (2) can be considered a special case of equation (3) when n=1. Equation (3) is called the hydropower complementarity equation.

[0039] When considering the initial division ratio of variables, equation (1) can be transformed into: (5) in H 0 =εH , ε The initial partition ratio is given by equation (4), which can be further transformed into: (6) Equation (6) can be considered as the form of equation (3) considering the initial allocation ratio. When fully considering the characteristics of the watershed underlying surface, equation (6) can be further written as: (7) In the formula, ε= H 0 / H Substitute into the above equation and let α = H 0 / H P After sorting, we get: D(8) Further assumptions β= H 0 / H P Then we have: (9) Right now (10) In equation (10), let a = (1-β n ) / [1-(αβ) n ] , b = (1-α n ) / [1- (αβ) n ] , a and b These can be considered as parameters that correct for changes in water and energy constraints on hydrological variables caused by preferential transformation of hydrological variables. Therefore: (11) Further transformation into: (12) make If we define this as the change in available water volume in a watershed caused by factors such as inter-basin water exchange, human influences (e.g., water diversion projects, reservoir interception), and climatic conditions (e.g., the inability of seasonal snowfall to be converted into usable water in a timely manner, and snowmelt from high mountains), then we have: (13) Equation (13) can be considered a generalized hydropower complementarity equation that takes into account the water volume obtained under the initial allocation ratio and the correction for energy constraints. Substituting GPP into H and aligning the dimensions, we get: (14) Solving the above equation yields: (15) The essence of the entire derivation is to construct a generalized hydrothermal complementarity model with water and energy constraints through mathematical transformations and physical transfer, and then apply it to the determination of the total primary productivity of terrestrial ecosystems, an eco-hydrological variable significantly constrained by water and energy. The logical chain is as follows: starting from the generalized proportion assumption, establishing the basic relationship between variables; introducing the hydro-energy complementarity equation to describe the nonlinear synergistic constraint of water and energy on H; considering the initial allocation ratio, extending the basic relationship; and by introducing intermediate parameters, transforming the equation into H with respect to H0. P and H E The weighted sum form is defined; the correction parameter I is defined to centrally express external disturbances (human activities, snowmelt, etc.); finally, the general hydrological variable H is set as GPP, H P Set the water-based productivity G(W), H E Setting the energy baseline productivity G(LUE) as the standard, we obtain the analytical expression for the generalized hydropower complementarity of GPP, which is the generalized hydropower complementarity total primary productivity model.

[0040] In the practical application of the generalized hydropower complementary total primary productivity model, the comprehensive coordination index, energy constraint correction parameter, and available water quantity correction parameter have clear physical meanings, and their reasonable value range is constrained by the ecosystem's hydropower coupling mechanism. If the parameter value range is not limited, the parameter calibration process will face an infinite search space, resulting in slow convergence of the optimization algorithm, high computational cost, and easy trapping in physically meaningless local optima, making the calibration results lack ecological interpretability.

[0041] To solve the above-mentioned technical problems, in some embodiments of the present invention, the value range of the comprehensive coordination index is 0.1 to 5, the value range of the energy limitation correction parameter is 0 to 1, and the value range of the available water correction parameter is -50 to 50.

[0042] In addition to the three parameters mentioned above that need to be calibrated, the range of values ​​for the maximum water use efficiency is also limited. The parameter value ranges are shown in Table 1. Table 1 Parameter Value Range

[0043] It should be understood that the range of parameter values ​​can be determined based on the statistical values ​​of historical data, and no specific limitation is made here.

[0044] By setting a reasonable range of parameter values, this invention not only limits the search space to a subspace that conforms to the physical laws of the ecosystem, but also significantly improves the convergence efficiency and calibration accuracy of the optimization algorithm. On the other hand, it effectively eliminates non-physical parameter combinations, ensuring that the calibrated model can truly reflect the hydropower synergistic constraint mechanism, thereby improving the model's generalization ability and estimation accuracy in different sites and regions.

[0045] In a specific embodiment of the present invention, the preset objective function is the Nash efficiency coefficient, and the Nash efficiency coefficient is: ; In the formula, NSE is the Nash efficiency coefficient. Let be the predicted total primary productivity of the terrestrial ecosystem at time i; Let be the measured value of total primary productivity of the terrestrial ecosystem at time i; m is the number of simulated months. This represents the average of the measured values ​​of total primary productivity of terrestrial ecosystems.

[0046] It should be understood that: the optimal objective function means the Nash efficiency coefficient is maximized.

[0047] In a specific embodiment of the present invention, the optimization algorithm used for calibration, which integrates coordination indicators, energy limitation correction parameters, and available water quantity correction parameters, is the SCE-UA (Shuffle Complex Evolutionary Algorithm) optimization algorithm. This is a global optimization algorithm adapted to the parameter calibration process of the generalized hydropower complementary total primary productivity model.

[0048] To ensure the accuracy of the estimation of eco-hydrological and meteorological data to be calculated, in some embodiments of the present invention, such as Figure 2 As shown, in step S104, before obtaining the total primary productivity of the target terrestrial ecosystem by inputting the eco-hydrological and meteorological data to be calculated into the calibrated generalized hydropower complementary total primary productivity model, the following steps are also included: S201. Input historical eco-hydrological and meteorological data into at least one existing gross primary productivity (GMP) prediction model to obtain at least one existing GMP prediction value. S202. Based on at least one existing total primary productivity (TPP) prediction value, terrestrial ecosystem TPP prediction value, terrestrial ecosystem TPP measured value, and preset evaluation indicators, determine whether the prediction accuracy of the generalized hydropower complementary TPP model is better than that of the existing TPP prediction model.

[0049] Then, in step S104, by inputting the eco-hydrological and meteorological data to be calculated into the calibrated generalized hydropower complementary total primary productivity model, the total primary productivity of the target terrestrial ecosystem is obtained as follows: When the prediction accuracy of the generalized hydropower complementary total primary productivity model is better than that of the existing total primary productivity prediction model, the target terrestrial ecosystem total primary productivity is obtained by inputting the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration.

[0050] In some embodiments of the present invention, the preset evaluation index includes at least one of Nash efficiency coefficient, Kling-Gupta efficiency coefficient (KGE), root mean square error, and coefficient of determination.

[0051] In a specific embodiment of the present invention, the existing total primary productivity prediction models are the LUE model and the Budyko-Yang model. Evaluation index values ​​for 40 stations with five consecutive years of valid data were extracted from the Global Micrometeorological Flux Observation Network (FLUXNET) dataset, and are shown in Table 2. Table 2 Evaluation index values ​​of GPP at each model monthly scale for 40 sites

[0052] As shown in Table 2, the generalized hydropower complementary total primary productivity model of this invention achieves significantly higher accuracy in various GPP monthly-scale simulations across 40 FLUXNET sites with significant differences in geographical location and climate conditions compared to existing models. This indicates that the generalized hydropower complementary total primary productivity model of this invention has strong applicability and application value. Therefore, it can be used to accurately determine the total primary productivity of terrestrial ecosystems.

[0053] In summary, the method for determining the total primary productivity (GPP) of terrestrial ecosystems proposed in this embodiment of the invention establishes an analytical expression for the carbon assimilation process of terrestrial ecosystems by constructing a unified generalized hydropower complementary GPP model, thereby achieving consistent estimation of GPP under different climatic conditions, vegetation types, and time scales.

[0054] On the other hand, embodiments of the present invention also provide a system for determining the total primary productivity of terrestrial ecosystems, such as... Figure 3 As shown, the terrestrial ecosystem total primary productivity determination system 300 includes: Historical data acquisition unit 301 is used to collect historical eco-hydrological and meteorological data of the study area and the measured value of total primary productivity of terrestrial ecosystems corresponding to the historical eco-hydrological and meteorological data. Model building unit 302 is used to construct a generalized hydropower complementary total primary productivity model. The generalized hydropower complementary total primary productivity model includes a comprehensive coordination index to reflect the ecosystem's total primary productivity baseline productivity under hydropower constraints, an energy constraint correction parameter to correct the calculation of effective radiation absorbed by plant photosynthesis and the conversion error of the total primary productivity baseline productivity, and an available water quantity correction parameter to correct the available water quantity under the influence of climate conditions and human activities. The generalized hydropower complementary total primary productivity model nonlinearly and complementaryly couples the water quantity constraint baseline productivity with the energy constraint baseline productivity through the comprehensive coordination index, the energy constraint correction parameter, and the available water quantity correction parameter. Model parameter calibration unit 303 is used to input historical eco-hydrological and meteorological data into the generalized hydropower complementary total primary productivity model to obtain the predicted value of total primary productivity of terrestrial ecosystem. Based on the measured value of total primary productivity of terrestrial ecosystem, and with the optimization of the preset objective function as the goal, the comprehensive coordination index, energy limitation correction parameter and available water correction parameter are calibrated. GPP determination unit 304 is used to acquire the eco-hydrological and meteorological data to be calculated in the study area, and input the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration to obtain the total primary productivity of the target terrestrial ecosystem.

[0055] The terrestrial ecosystem total primary productivity determination system 300 provided in the above embodiments can realize the technical solutions described in the above embodiments of the terrestrial ecosystem total primary productivity determination method. The specific implementation principles of each module or unit can be found in the corresponding content in the above embodiments of the terrestrial ecosystem total primary productivity determination method, and will not be repeated here.

[0056] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0057] The present invention provides a detailed description of a method and system for determining the total primary productivity of a terrestrial ecosystem. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the invention. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the invention. Therefore, the content of this specification should not be construed as a limitation of the invention.

Claims

1. A method for determining the total primary productivity of a terrestrial ecosystem, characterized in that, include: Historical eco-hydrological and meteorological data of the study area and the measured values ​​of total primary productivity of terrestrial ecosystems corresponding to the historical eco-hydrological and meteorological data were collected. A generalized hydropower complementary total primary productivity model is constructed, comprising a comprehensive coordination index reflecting the ecosystem's baseline productivity of total primary productivity under hydropower constraints, an energy constraint correction parameter for correcting the calculation of effective radiation absorbed by plant photosynthesis and the conversion error of the baseline productivity of total primary productivity, and an available water quantity correction parameter for correcting the available water quantity under the influence of climate conditions and human activities. The generalized hydropower complementary total primary productivity model nonlinearly and complementaryly couples the water quantity constraint baseline productivity with the energy constraint baseline productivity through the comprehensive coordination index, the energy constraint correction parameter, and the available water quantity correction parameter. The historical eco-hydrological and meteorological data are input into the generalized hydropower complementary total primary productivity model to obtain the predicted value of the total primary productivity of the terrestrial ecosystem. Based on the measured value of the total primary productivity of the terrestrial ecosystem, and with the optimization of the preset objective function as the goal, the comprehensive coordination index, the energy limitation correction parameter, and the available water correction parameter are calibrated. Obtain the eco-hydrological and meteorological data to be calculated for the study area, and input the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration to obtain the total primary productivity of the target terrestrial ecosystem.

2. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 1, characterized in that, The generalized hydropower complementary total primary productivity model is as follows: ； In the formula, GPP is the predicted total primary productivity of terrestrial ecosystems; G(LUE) is the energy baseline productivity; and G(W+I) is the water baseline productivity. n represents the comprehensive coordination index; b represents the energy limitation correction parameter. I represents the available water quantity correction parameter.

3. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 2, characterized in that, The value range of the comprehensive coordination index is 0.1 to 5, the value range of the energy limitation correction parameter is 0 to 1, and the value range of the available water correction parameter is -50 to 50.

4. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 2, characterized in that, The energy baseline productivity is: ； In the formula, APAR represents the absorbed photosynthetically active radiation; ε FRAR is the photosynthetically active radiation ratio; PAR is the solar effective radiation ratio. Temperature stress factor; VPD is the regional saturated vapor pressure difference stress factor; VPD is the regional saturated vapor pressure difference. The maximum regional saturated vapor pressure difference for plants to perform photosynthesis; The minimum saturated vapor pressure difference required for plants to perform photosynthesis; The minimum threshold temperature for plants to perform photosynthesis; The maximum threshold for the minimum temperature at which plants can perform photosynthesis.

5. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 2, characterized in that, The water quantity baseline productivity is: ； In the formula, W represents net effective moisture; θ max P represents the maximum water use efficiency; P represents the total effective water consumption. △ S This represents the change in soil moisture content; △ Snow This represents the change in snow depth equivalent.

6. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 1, characterized in that, The preset objective function is the Nash efficiency coefficient, which is: ； In the formula, NSE is the Nash efficiency coefficient. Let be the predicted total primary productivity of the terrestrial ecosystem at time i; Let be the measured value of total primary productivity of the terrestrial ecosystem at time i; m is the number of simulated months. This represents the average of the measured values ​​of total primary productivity of terrestrial ecosystems.

7. The method for determining the total primary productivity of a terrestrial ecosystem according to any one of claims 1-6, characterized in that, The optimization algorithm used for the calibration of the comprehensive coordination index, the energy limitation correction parameter, and the available water correction parameter is the SCE-UA optimization algorithm.

8. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 1, characterized in that, Before obtaining the total primary productivity of the target terrestrial ecosystem in the generalized hydropower complementary total primary productivity model after the input parameters of the eco-hydrological and meteorological data to be calculated are calibrated, the method further includes: Input the historical eco-hydrological and meteorological data into at least one existing gross primary productivity prediction model to obtain at least one existing gross primary productivity prediction value; Based on the at least one existing total primary productivity (TPP) prediction value, the terrestrial ecosystem TPP prediction value, the terrestrial ecosystem TPP measured value, and the preset evaluation index, determine whether the prediction accuracy of the generalized hydropower complementary TPP model is better than that of the existing TPP prediction model. The total primary productivity of the target terrestrial ecosystem is obtained from the generalized hydropower complementary total primary productivity model after the input parameters of the eco-hydrological and meteorological data to be calculated are calibrated, including: When the prediction accuracy of the generalized hydropower complementary total primary productivity model is better than that of the existing total primary productivity prediction model, the target terrestrial ecosystem total primary productivity is obtained by inputting the eco-hydrological and meteorological data to be calculated into the parameter-calibrated generalized hydropower complementary total primary productivity model.

9. The method for determining the total primary productivity of a terrestrial ecosystem according to claim 8, characterized in that, The preset evaluation indicators include at least one of the following: Nash efficiency coefficient, Kling-Gupta efficiency coefficient, root mean square error, and coefficient of determination.

10. A system for determining the total primary productivity of a terrestrial ecosystem, characterized in that, include: The historical data acquisition unit is used to collect historical eco-hydrological and meteorological data of the study area and the measured values ​​of total primary productivity of the terrestrial ecosystem corresponding to the historical eco-hydrological and meteorological data. The model building unit is used to construct a generalized hydropower complementary total primary productivity model. This model includes a comprehensive coordination index reflecting the ecosystem's response to the baseline productivity of total primary productivity under hydropower constraints, an energy constraint correction parameter for correcting the calculation of effective radiation absorbed by plant photosynthesis and the conversion error of the baseline productivity, and an available water quantity correction parameter for correcting the available water quantity under the influence of climate conditions and human activities. The generalized hydropower complementary total primary productivity model nonlinearly and complementaryly couples the water quantity constraint baseline productivity with the energy constraint baseline productivity through the comprehensive coordination index, the energy constraint correction parameter, and the available water quantity correction parameter. The model parameter calibration unit is used to input the historical eco-hydrological and meteorological data into the generalized hydropower complementary total primary productivity model to obtain the predicted value of the total primary productivity of the terrestrial ecosystem. Based on the measured value of the total primary productivity of the terrestrial ecosystem, and with the optimization of the preset objective function as the objective, the comprehensive coordination index, the energy limitation correction parameter, and the available water correction parameter are calibrated. The GPP determination unit is used to acquire the eco-hydrological and meteorological data to be calculated in the study area, and input the eco-hydrological and meteorological data to be calculated into the generalized hydropower complementary total primary productivity model after parameter calibration to obtain the total primary productivity of the target terrestrial ecosystem.

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