A method for improving the simulation accuracy of isotope fractionation in atmospheric chemical transport models

Abstract

This invention relates to the field of atmospheric chemical numerical simulation and isotope tracing technology, and provides a method to improve the accuracy of isotope fractionation simulation in atmospheric chemical transport models. The method involves: determining the comprehensive apparent isotope fractionation coefficient and total reaction ratio of reactants to products within the main time step based on the molar concentrations of reactants and products before and after the chemical reaction process within the main time step, and the relative conversion rate of products under different reaction pathways; dividing the time step into multiple sub-time steps when the total reaction ratio exceeds a threshold; and then determining the molar concentration and isotope ratio of each isotope in the reactants and products within each sub-time step based on the comprehensive apparent isotope fractionation coefficient, the molar concentrations of reactants and products in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants, thereby achieving a more realistic and higher-precision numerical simulation of the atmospheric isotope fractionation process.

Description

Technical Field

[0001] This invention relates to the field of atmospheric chemical numerical simulation and isotope tracing technology, and in particular to a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models. Background Technology

[0002] Accurately analyze fine particulate matter in the atmosphere (such as PM2.5) 2.5 Identifying the sources of secondary components in pollutants is crucial for developing effective pollution control measures. Isotope tracing technology, especially the coupling of isotope fractionation characteristics with atmospheric chemical transport models, provides a powerful technical means to trace the sources and evolution of pollutants on a three-dimensional spatiotemporal scale.

[0003] In existing technologies, a complete framework for coupling isotope chemical fractionation modules (such as sulfur isotopes) into three-dimensional atmospheric chemical transport models has been proposed. This algorithm, by creating a multi-nucleotope-labeled emission source inventory and coupling the isotope fractionation module into the atmospheric chemical transport model, combined with the Rayleigh fractionation formula, calculates the changes in the isotope ratio of reactants to products during chemical reactions. This represents a shift from single-nucleotope simulation to multi-nucleotope tracer simulation, providing a new technique for tracing the sources of secondary inorganic aerosols. However, when applied to long-term simulations of real, dynamically changing atmospheric environments, the following technical bottlenecks were found, affecting its simulation accuracy and applicability: 1) In the actual atmosphere, the precursor SO2 is converted into sulfate through multiple reaction pathways, including gas-phase OH oxidation, liquid-phase H2O2 oxidation, O3 oxidation, and transition metal ion catalytic oxidation. Each reaction pathway has its unique instantaneous isotopic fractionation coefficient, which varies with conditions such as temperature.

[0004] The existing algorithmic framework is based on the assumption of a single reaction pathway. This makes it impossible to accurately calculate the overall apparent fractionation effect when multiple reaction pathways occur simultaneously, jointly consuming reactants and generating products. If only the fractionation results of each individual pathway are summed, the combined isotopic fractionation effect of different reaction pathways within the same time step will be ignored, and the isotopic characteristics of reactants and products cannot be accurately characterized.

[0005] 2) Existing technologies use the Rayleigh fractionation formula to describe the isotope fractionation process. This formula assumes that one phase of the substance continuously leaves the reaction system after separation, and that the separated phase no longer exchanges isotopes with the remaining phase. At the same time, the reactants only exit and do not enter, and it is assumed that there is no external input or mixing during the entire reaction process.

[0006] However, in the real atmosphere, mixing and fractionation occur simultaneously. Within each integration step of an atmospheric chemical transport model, reactants are consumed not only through chemical reactions but also exchanged through processes such as advection and diffusion. The Rayleigh fractionation model only considers the one-way loss of reactants, neglecting the continuous influx of fresh reactants. This leads to systematic biases in the calculation of the isotopic composition of the remaining reactant reservoir, potentially directly affecting the accuracy of pollution source apportionment results based on isotope techniques. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models.

[0008] This invention provides a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, comprising: Based on the isotopic fingerprint source spectrum library of atmospheric chemical species, construct a model-driven multi-nucleotope labeling isotopic emission source inventory. Using the model-driven multi-nucleotope-labeled isotope emission source inventory, combined with a preset meteorological field and initial boundary conditions, an atmospheric chemical transport model is driven to determine the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, as well as the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step. Based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step, the comprehensive apparent isotopic fractionation coefficient from reactants to products and the total reaction ratio within the current main time step are determined during the chemical reaction process within the current main time step. When the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is time-divided to obtain multiple sub-time steps. Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process within the current sub-time step are determined.

[0009] According to the present invention, a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, wherein determining the relative conversion rates of products under different reaction pathways during a chemical reaction process within the current master time step includes: Obtain the net change in the molar concentration of the products under different reaction pathways within the current main time step; Based on the net change, the relative conversion rate of the products in each reaction pathway is obtained.

[0010] According to the present invention, a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models is provided. The method involves determining the comprehensive apparent isotope fractionation coefficient from reactants to products and the total reaction proportion within the current main time step, based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways within the current main time step. Based on the molar concentration of reactants before and after the chemical reaction process within the current main time step, the remaining proportion of reactants during the chemical reaction process within the current main time step is obtained. Based on the remaining proportion, the total reaction proportion within the current main time step is obtained; Based on the relative conversion rates of products under different reaction pathways in the chemical reaction process within the current main time step, and the isotopic fractionation coefficients of isotopes under different reaction pathways, the comprehensive apparent isotopic fractionation coefficients from reactants to products in the chemical reaction process within the current main time step are obtained.

[0011] According to the present invention, a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, within the current sub-time step, determines the concentration and isotope ratio of each isotope in the reactants and products after the chemical reaction process in the previous sub-time step based on the comprehensive apparent isotope fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the sub-time step, including: Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current sub-time step is obtained by taking into account the comprehensive apparent isotope fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. Based on the isotopic material balance relationship, according to the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratio of reactants and products in the current sub-time step, the change in molar concentration of each isotope after the chemical reaction process in the current sub-time step is obtained. Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, determine the molar concentration and isotope ratio of each isotope in the pre-mixed reactants after the chemical reaction process within the current sub-time step. Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, determine the molar concentration and isotope ratio of each isotope in the product after the chemical reaction process within the current sub-time step. Based on the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step is obtained.

[0012] According to the present invention, a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models is provided. The method, based on the Rayleigh fractionation formula, obtains the isotope ratio of reactants and products in the current sub-time step by considering the comprehensive apparent isotope fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. The method includes: Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current sub-time step is obtained by using the following calculation formula based on the comprehensive apparent isotopic fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. ; ; ; in, and Each represents the previous time step. isubstep -1 Internal reactants Medium and heavy isotopes and light isotopes The molar concentration of the substance; Reactants within the previous time step isotope ratios; and These are the current sub-time steps. isubstep Internal reactants and products P isotope ratios; The reactants in the chemical reaction process within the current master time step To the product P The overall apparent isotopic fractionation coefficient, The reactants in the chemical reaction process within the current master time step The remaining proportion, This represents the proportion of the total reaction within the current master time step.

[0013] According to the present invention, a method for improving the simulation accuracy of isotope fractionation in atmospheric chemical transport models is provided. The method, based on isotope mass balance relationships, obtains the change in the mass concentration of each isotope after the chemical reaction process in the current sub-time step, according to the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step and the isotope ratios of reactants and products in the current sub-time step. The method includes: Based on the isotopic material balance relationship, the following calculation formula is used to obtain the change in the concentration of each isotope after the chemical reaction process in the current sub-time step, according to the molar concentration of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratio of reactants and products in the current sub-time step. = / ; ; in, and These represent the current sub-time step during the chemical reaction process. isubstep internal heavy isotope and light isotopes The change in the molar concentration of the substance.

[0014] According to the present invention, a method for improving the simulation accuracy of isotope fractionation in atmospheric chemical transport models is provided, wherein determining the molar concentration of each isotope in the pre-mixing reactants after the chemical reaction process within the current sub-time step, based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, includes: Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, the molar concentration of each isotope in the pre-mixed reactants after the chemical reaction process within the current sub-time step is determined using the following calculation formula. ; ; in, and These are the current sub-time steps. isubstep Mixed pre-reactants Medium and heavy isotopes and light isotopes The molar concentration of a substance.

[0015] According to the present invention, a method for improving the simulation accuracy of isotope fractionation in atmospheric chemical transport models is provided, wherein determining the molar concentration of each isotope in the products after the chemical reaction process within the current sub-time step based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step includes: Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, the molar concentration of each isotope in the product after the chemical reaction process within the current sub-time step is determined using the following calculation formula. ; ; in, and Each represents the previous time step. isubstep -1 and the current sub-time step isubstep Products P Medium and heavy isotopes The molar concentration of the substance; and Each represents the previous time step. isubstep -1 and the current sub-time step isubstep Products P medium light isotope The molar concentration of a substance.

[0016] According to the present invention, a method for improving the simulation accuracy of isotope fractionation in an atmospheric chemical transport model is provided, wherein obtaining the molar concentration of reactants after mixing in the chemical reaction process within the current sub-time step is based on the molar concentration of reactants before mixing in the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, includes: Based on the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step is obtained through the following calculation formula. ; ; in, and These are the current sub-time steps. isubstep The reactants after mixing Medium and heavy isotopes and light isotopes The molar concentration of the substance; and Freshly mixed reactants within sub-time steps Medium and heavy isotopes and light isotopes The molar concentration of a substance.

[0017] The present invention also provides an apparatus for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, comprising: A module is built to construct an isotopic emission source inventory that conforms to model-driven multi-nucleotope labeling based on an isotopic fingerprint source library of atmospheric chemical species. The first determining module is used to drive an atmospheric chemical transport model based on the multi-nucleotope-labeled isotope emission source inventory driven by the conforming mode, combined with a preset meteorological field and initial boundary conditions, to determine the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and to determine the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step. The second determining module is used to determine the comprehensive apparent isotopic fractionation coefficient of reactants to products and the total reaction ratio within the current main time step based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction paths during the chemical reaction process within the current main time step. The partitioning module is used to divide the current main time step into multiple sub-time steps when the total reaction ratio within the current main time step is greater than a preset threshold. The third determining module is used to determine, within the current sub-time step, the concentration of each isotope in the reactants and products after the chemical reaction process in the previous sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentration of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentration of different isotopes in the freshly mixed reactants in the current sub-time step, and the molar concentration of each isotope in the reactants after the chemical reaction process in the current sub-time step.

[0018] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement any of the methods described above for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes.

[0019] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the methods described above for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes.

[0020] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements any of the methods described above for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes.

[0021] This invention provides a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models. After driving the atmospheric chemical transport model, based on the molar concentrations of reactants and products before and after the chemical reaction process within the current master time step, and the relative conversion rates of products under different reaction pathways within the current master time step, the method determines the comprehensive apparent isotope fractionation coefficient from reactants to products and the total reaction proportion within the current master time step. When the total reaction proportion within the current master time step exceeds a preset threshold, the current master time step is time-divided to obtain multiple... Within a sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants in the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process in the current sub-time step are determined. This enables a more realistic and accurate numerical simulation of the atmospheric isotopic fractionation process, thereby improving the accuracy of atmospheric isotopic fractionation simulation and providing more reliable technical support for isotopic tracing-based analysis of atmospheric pollution sources. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating the method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models provided by the present invention.

[0024] Figure 2 This is a schematic diagram of the overall process of the method for improving the simulation accuracy of isotope fractionation in atmospheric chemical transport modes provided by the present invention.

[0025] Figure 3 This is a schematic diagram of the device provided by the present invention for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes.

[0026] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] Figure 1 This invention provides a schematic flowchart of a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models. (See attached diagram.) Figure 1 The method includes the following steps: Step 11: Based on the isotopic fingerprint source library of atmospheric chemical species, construct a model-driven multi-nucleotope labeling isotopic emission source inventory.

[0030] Step 12: Using a model-driven multi-nucleotope-labeled isotope emission source inventory, combined with a preset meteorological field and initial boundary conditions, drive an atmospheric chemical transport model to determine the molar concentrations of reactants and products before and after the chemical reaction process within the current master time step, and to determine the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step.

[0031] Step 13: Based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step, determine the comprehensive apparent isotopic fractionation coefficients from reactants to products and the total reaction ratio within the current main time step.

[0032] Step 14: When the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is divided into multiple sub-time steps.

[0033] Step 15: Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, determine the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process within the current sub-time step.

[0034] Regarding steps 11 to 15, it should be noted that in this invention, to achieve three-dimensional simulation of a chemical species from a single nuclide to multiple nuclides of its different isotopes, it is necessary to first integrate the isotopic fingerprint source spectrum library with the emission source species and perform quasi-model access. Based on the characteristics of the isotopic fingerprint source spectrum libraries of different species, and based on the isotopic ratio algorithm and the isotopic mass balance principle, the emission inventories of key elements in different industries and regions are allocated using the isotopic fingerprint source spectrum library to create an isotopic emission source inventory that conforms to model-driven multi-nucleotope labeling.

[0035] After species are multi-dimensionalized using nuclides, a model-driven multi-nucleotope-labeled isotope emission source inventory, combined with meteorological fields and initial boundary conditions, drives a global-regional multi-scale nested grid air quality forecasting model to label different gas-phase and liquid-phase chemical reaction processes. Specifically, the model-driven multi-nucleotope-labeled isotope emission source inventory, combined with preset meteorological fields and initial boundary conditions, drives an atmospheric chemical transport model to determine the molar concentrations of reactants and products before and after a chemical reaction process within the current master time step, as well as the relative conversion rates of products under different reaction pathways within the current master time step. It should be noted that the master time step here is the complete calculation time length for one chemical reaction under the atmospheric chemical transport model.

[0036] Following the driving atmospheric chemical transport model, the reactants before and after the chemical reaction process within the current master time step are labeled. and products P The molar concentration of substances. That is, the reactants are directly exported via atmospheric chemical transport models. and products P The molar concentration. Whether reactants or products, chemical reactions are quantified using molar concentration. Molar concentration refers to the amount of solute contained in a unit volume of solution. A substance has multiple isotopes; isotopes are molecules with the same molecular formula but with one or more atoms replaced by isotopes. Different isotopes of the same substance have different molecular masses; the lighter isotopes are those with smaller relative molecular masses, and the heavier isotopes are those with larger relative molecular masses. This is how the reactants before and after the chemical reaction process within the current master time step are marked and recorded. and products P The molar concentration can be further divided into the molar concentrations of heavy isotopes and light isotopes in the reactants.

[0037] In the actual atmosphere, reactant SO2 is converted into sulfate via multiple reaction pathways, including gas-phase OH oxidation, liquid-phase H2O2 oxidation, O3 oxidation, and transition metal ion catalytic oxidation. The contribution percentage of each pathway to sulfate formation, i.e., the relative conversion rate of products under different reaction pathways, is the key foundational data for calculating the multi-path apparent fractionation coefficient. Therefore, this invention also needs to determine the relative conversion rate of products under different reaction pathways during the chemical reaction process within the current main time step.

[0038] In this invention, the concentration ratio of reactants before and after the main time step is used to calculate the remaining proportion of reactants in the current main time step. The difference between this ratio and 1 is the total reaction proportion in that main time step, providing basic data for subsequent separation of the relative conversion of each reaction path and solving the multi-path comprehensive apparent fractionation coefficient.

[0039] In this invention, the traditional Rayleigh fractionation model assumes that the reactant reservoir is a closed system, with only one path: consumption by the reaction, and no replenishment by fresh reactants. However, in the real atmosphere, the reservoir is an open system. Reactants are both consumed by chemical reactions and replenished by fresh reactants through advection and diffusion. Continuing to calculate according to the traditional model is problematic because the model step size is too large to capture this dynamic balance of simultaneous consumption and replenishment, leading to systematic biases in the isotopic composition. Therefore, the large main time step is broken down into multiple sub-time steps. This allows the model to synchronously update the chemical consumption and physical replenishment processes of reactants within each smaller time step, accurately tracking the dynamic changes in the reservoir's isotopic composition and effectively mitigating the systematic biases caused by the reservoir effect.

[0040] In this invention, when the total reaction ratio is low, the reactant concentration changes gradually, and the main time step can be used directly for calculation; when the total reaction ratio is high, the reactant concentration changes drastically, and the concentration and reaction state are updated successively by dividing the time step into sub-time steps, effectively controlling the reservoir effect deviation. Therefore, when the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is divided into multiple sub-time steps.

[0041] After dividing the main time step into sub-time steps, the process iteratively determines the chemical reaction consumption and atmospheric mixing of fresh reactants within the current sub-time step. Based on the calculated comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process in each sub-time step are determined. This invention's method of processing molar concentrations and isotopic ratios within each sub-time step can capture the dynamic process of reactant consumption, fresh substance mixing, and isotopic fractionation evolution within a single sub-time step in real time. This effectively reduces the systematic bias in isotopic calculations caused by the atmospheric reservoir effect and avoids the inaccuracy of isotopic ratios caused by large-time-step averaging calculations.

[0042] A further method described above primarily explains the process of determining the relative conversion rates of products along different reaction pathways during a chemical reaction within the current master time step, as detailed below: Obtain the net change in the molar concentration of the products under different reaction pathways within the current main time step; Based on the net change, the relative conversion rate of the products in each reaction pathway is obtained.

[0043] It should be noted that, within the current principal time step (the duration of the principal time step from time t-1 to time t), the net change in the molar concentration of the products in different reaction pathways at time t is marked, and the relative conversion rate of each reaction pathway is calculated simultaneously, as shown in the following formula: ; in, for i Reaction pathway t Product of time P The net change in the molar concentration of the substance. for i Reaction pathway for products P The relative conversion rate n This represents the number of reaction pathways.

[0044] Furthermore, the explanation focuses on the process of determining the comprehensive apparent isotopic fractionation coefficient of reactants to products and the total reaction ratio within the current main time step, based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways within the current main time step. The details are as follows: Based on the molar concentration of reactants before and after the chemical reaction process within the current main time step, obtain the remaining proportion of reactants during the chemical reaction process within the current main time step; Based on the remaining proportion, obtain the total reaction proportion within the current main time step; Based on the relative conversion rates of products under different reaction pathways in the chemical reaction process within the current master time step, and the isotopic fractionation coefficients of isotopes under different reaction pathways, the comprehensive apparent isotopic fractionation coefficients from reactants to products in the chemical reaction process within the current master time step are obtained.

[0045] It should be noted that in this invention, the molar concentrations of reactants before and after the chemical reaction process within the current main time step are obtained, i.e., the molar concentrations of reactants at time t-1 and after time t of the chemical reaction process, and the remaining proportion of reactants at time t is calculated as follows: f rem =C Q,t / C Q,t-1 ; Among them, C Q,t-1 and C Q,t They are respectively t -1 and t Reactants at time concentration, f rem This represents the remaining proportion of reactants.

[0046] Based on the remaining proportion, obtain the total reaction proportion within the current master time step. This is the total reaction proportion for the current master time step. f total ,in f total = 1 - f rem .

[0047] In this invention, the comprehensive apparent isotopic fractionation coefficient from reactants to products in the chemical reaction process within the current main time step is obtained based on the relative conversion rate of products under different reaction paths in the chemical reaction process within the current main time step, and the isotopic fractionation coefficient of isotopes under different reaction paths.

[0048] It should be noted that, firstly, the isotopic fractionation coefficients for different reaction pathways are calculated, as shown in the following formula: ; in, for i Reaction pathway heavy isotope The isotopic fractionation coefficient, i.e., the productP and reactants Inter-isotope The degree of fractionation; For i-reaction pathway heavy isotopes under 275K conditions isotopic fractionation coefficient; This is a constant representing the isotopic fractionation coefficient as a function of temperature. Temperature is in Celsius.

[0049] When reactants are chemically consumed simultaneously through n reaction pathways, the chemical reaction process (reactants) To the product P The comprehensive apparent isotopic fractionation coefficient The weighted calculation is obtained from the isotopic fractionation coefficients of each path, as shown in the following formula: .

[0050] Furthermore, the explanation focuses on the process of determining the concentrations and isotope ratios of various isotopes in the reactants and products after the chemical reaction process in the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants in the current sub-time step. The details are as follows: Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current sub-time step is obtained by taking into account the comprehensive apparent isotope fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. Based on the isotopic material balance relationship, according to the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratio of reactants and products in the current sub-time step, the change in molar concentration of each isotope after the chemical reaction process in the current sub-time step is obtained. Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, determine the molar concentration and isotope ratio of each isotope in the pre-mixed reactants after the chemical reaction process within the current sub-time step. Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, determine the molar concentration and isotope ratio of each isotope in the product after the chemical reaction process within the current sub-time step. Based on the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step is obtained.

[0051] It should be noted that within each major time step, the total response ratio for that major time step is calculated. f total ,in f total = 1 - f rem The preferred threshold for the reaction ratio (θ) within the sub-time step is 2%. f total If the value is greater than θ, then the main time step is divided into several sub-time steps. N substep This ensures that the reaction proportion within each sub-time step does not exceed θ. Simultaneously, the molar concentrations of different isotopes in the freshly mixed reactants are calculated within each sub-time step, assuming a linear distribution of the fresh mixing process within the sub-time steps, as shown in the following formula: ; .

[0052] in, and Heavy isotopes in freshly mixed reactants within each sub-time step and light isotopes The molar concentration of the substance. and Heavy isotopes in freshly mixed reactants at time t (i.e., the principal time step t) and light isotopes The molar concentration of the substance. This represents the total number of sub-time steps.

[0053] Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current sub-time step is obtained by using the following calculation formula based on the comprehensive apparent isotopic fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. ; ; ; in, and Each represents the previous time step. isubstep -1 Internal reactants Medium and heavy isotopes and light isotopes The molar concentration of the substance; Reactants within the previous time step isotope ratios; and These are the current sub-time steps. isubstep Internal reactants and products P isotope ratios; The reactants in the chemical reaction process within the current master time step To the product P The overall apparent isotopic fractionation coefficient, The reactants in the chemical reaction process within the current master time step The remaining proportion, This represents the proportion of the total reaction within the current master time step.

[0054] Based on the isotopic material balance relationship, the following calculation formula is used to obtain the change in the concentration of each isotope after the chemical reaction process in the current sub-time step, according to the molar concentration of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratio of reactants and products in the current sub-time step. ; = / ; in, and These represent the current sub-time step during the chemical reaction process. isubstep internal heavy isotope and light isotopes The change in the molar concentration of the substance.

[0055] Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, the molar concentration of each isotope in the pre-mixed reactants after the chemical reaction process within the current sub-time step is determined using the following calculation formula. ; ; in, and These are the current sub-time steps. isubstep Mixed pre-reactants Medium and heavy isotopes and light isotopes The molar concentration of a substance.

[0056] Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, the molar concentration of each isotope in the product after the chemical reaction process within the current sub-time step is determined using the following calculation formula. ; ; in, and Each represents the previous time step. isubstep -1 and the current sub-time step isubstep Products P Medium and heavy isotopes The molar concentration of the substance; and Each represents the previous time step. isubstep -1 and the current sub-time step isubstep Products P medium light isotope The molar concentration of a substance.

[0057] Based on the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step is obtained through the following calculation formula. ; ; in, These are the current sub-time steps. isubstep The reactants after mixing Medium and heavy isotopes and light isotopes The molar concentration of the substance; and Freshly mixed reactants within sub-time steps Medium and heavy isotopes and light isotopes The molar concentration of a substance.

[0058] It should be noted that the method of processing the molar concentration and isotope ratio within each sub-time step of this invention can capture the dynamic process of reactant consumption, fresh substance incorporation, and isotope fractionation evolution within a single sub-time step in real time, effectively reducing the systematic bias in isotope calculations caused by the atmospheric reservoir effect. To this end, it is necessary to first capture the reactant consumption within a single sub-time step, and then the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step; then, combined with the incorporation of fresh substances, to obtain the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step. The molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step can be used as the input concentration information for the next main time step.

[0059] After obtaining the molar concentration, if the current sub-time step is not the last sub-time step, the isotope ratio of each isotope in the reactants within the current sub-time step is calculated using the following formula: .

[0060] If the current sub-time step is the last sub-time step, the isotope ratios of the isotopes in the reactants within the current sub-time step are calculated using the following formula: .

[0061] It should also be noted that in this invention, when the total reaction ratio is low, the reactant concentration changes gradually, and the main time step can be used directly for calculation.

[0062] Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current main time step is obtained by taking into account the comprehensive apparent isotope fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous main time step. Based on isotopic equilibrium, the molar concentrations of reactants and products after the chemical reaction process in the previous principal time step are obtained according to the molar concentrations of reactants and products after the chemical reaction process in the previous principal time step and the isotopic ratios of reactants and products in the current principal time step.

[0063] See Figure 2 A schematic diagram of the overall process for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models.

[0064] Taking the conversion of SO2 to sulfate in the atmosphere as an example, the maximum absolute value of the difference is mainly distributed in Antarctica and ocean regions. These regions have low SO2 emissions and high reaction rates, and are most affected by the SO2 reservoir effect. After optimization, Δδ 34 S_SO4 2-The simulated value of SO2 decreased by -3.0‰ to -1.5‰; in areas with intensive human activities, although SO2 emissions are high and the reservoir effect is relatively reduced, the emission mixing process still has a significant impact on Δδ. 34 S_SO4 2- The simulation impact of SO2 is also not negligible; after algorithm optimization, Δδ in some regions... 34 S_SO4 2- The simulated SO2 value increased by 0.3‰ to 1.0‰. The iterative time division method effectively overcomes the simulation errors caused by time discretization and the mixing effect of open systems, and the simulation accuracy of sulfur isotope fractionation effect is significantly improved.

[0065] The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models provided by this invention determines the comprehensive apparent isotope fractionation coefficient from reactants to products and the total reaction proportion within the current main time step based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, as well as the relative conversion rates of products under different reaction pathways within the current main time step, after driving the atmospheric chemical transport model. When the total reaction proportion within the current main time step exceeds a preset threshold, the current main time step is time-divided into multiple sub-time steps. By defining a time step, and then within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants in the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process in the current sub-time step are determined. This enables a more realistic and accurate numerical simulation of the atmospheric isotopic fractionation process, thereby improving the accuracy of atmospheric isotopic fractionation simulation and providing more reliable technical support for isotopic tracing-based analysis of atmospheric pollution sources.

[0066] The apparatus for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes provided by the present invention will be described below. The apparatus for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes described below can be referred to in correspondence with the method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport modes described above.

[0067] Figure 3 This invention provides a schematic diagram of a device for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models. (See attached diagram.) Figure 3 The device includes a construction module 41, a first determining module 42, a second determining module 43, a dividing module 44, and a third determining module 45, wherein: Module 41 is used to construct an isotopic fingerprint source library based on atmospheric chemical species and to build an isotopic emission source inventory that conforms to model-driven multi-nucleotope labeling. The first determining module 42 is used to drive an atmospheric chemical transport model with a multi-nucleotope-labeled isotope emission source inventory driven by a conformity model, combined with a preset meteorological field and initial boundary conditions, to determine the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and to determine the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step. The second determining module 43 is used to determine the comprehensive apparent isotopic fractionation coefficient of reactants to products and the total reaction ratio in the current main time step based on the molar concentrations of reactants and products before and after the chemical reaction process in the current main time step, and the relative conversion rate of products under different reaction paths in the chemical reaction process in the current main time step. The partitioning module 44 is used to divide the current main time step into multiple sub-time steps when the total reaction ratio within the current main time step is greater than a preset threshold. The third determining module 45 is used to determine the concentration and isotope ratio of each isotope in the reactants and products after the chemical reaction process in the current sub-time step, based on the comprehensive apparent isotope fractionation coefficient, the molar concentration of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentration of different isotopes in the freshly mixed reactants in the current sub-time step.

[0068] Since the apparatus of this embodiment is based on the same principle as the method of the above embodiment, more detailed explanations will not be repeated here.

[0069] It should be noted that, in the embodiments of the present invention, the relevant functional modules can be implemented by a hardware processor.

[0070] The device provided by this invention for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models determines the comprehensive apparent isotope fractionation coefficient from reactants to products and the total reaction ratio within the current main time step after driving the atmospheric chemical transport model, based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways within the current main time step. When the total reaction ratio within the current main time step exceeds a preset threshold, the current main time step is time-divided into multiple sub-time steps. By defining a time step, and then within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants in the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process in the current sub-time step are determined. This enables a more realistic and accurate numerical simulation of the atmospheric isotopic fractionation process, thereby improving the accuracy of atmospheric isotopic fractionation simulation and providing more reliable technical support for isotopic tracing-based analysis of atmospheric pollution sources.

[0071] Figure 4 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 4 As shown, the electronic device may include: a processor 51, a communication interface 52, a memory 53, and a communication bus 54, wherein the processor 51, the communication interface 52, and the memory 53 communicate with each other via the communication bus 54. The processor 51 can call logical instructions in the memory 53 to execute a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, the method including: Based on the isotopic fingerprint source spectrum library of atmospheric chemical species, construct a model-driven multi-nucleotope labeling isotopic emission source inventory. Using a model-driven multi-nucleotope-labeled isotope emission source inventory, combined with a preset meteorological field and initial boundary conditions, an atmospheric chemical transport model is driven to determine the molar concentrations of reactants and products before and after a chemical reaction process within the current master time step, as well as the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step. Based on the molar concentrations of reactants and products before and after the chemical reaction process within the current master time step, and the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step, determine the comprehensive apparent isotopic fractionation coefficients from reactants to products and the total reaction ratio within the current master time step during the chemical reaction process. When the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is divided into multiple sub-time steps. Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process within the current sub-time step are determined.

[0072] Furthermore, the logical instructions in the aforementioned memory 53 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0073] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program that can be stored on a non-transitory computer-readable storage medium, wherein when the computer program is executed by a processor, the computer is capable of performing the methods provided above for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, the method comprising: Based on the isotopic fingerprint source spectrum library of atmospheric chemical species, construct a model-driven multi-nucleotope labeling isotopic emission source inventory. Using a model-driven multi-nucleotope-labeled isotope emission source inventory, combined with a preset meteorological field and initial boundary conditions, an atmospheric chemical transport model is driven to determine the molar concentrations of reactants and products before and after a chemical reaction process within the current master time step, as well as the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step. Based on the molar concentrations of reactants and products before and after the chemical reaction process within the current master time step, and the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step, determine the comprehensive apparent isotopic fractionation coefficients from reactants to products and the total reaction ratio within the current master time step during the chemical reaction process. When the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is divided into multiple sub-time steps. Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process within the current sub-time step are determined.

[0074] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models provided by the methods described above, the method comprising: Based on the isotopic fingerprint source spectrum library of atmospheric chemical species, construct a model-driven multi-nucleotope labeling isotopic emission source inventory. Using a model-driven multi-nucleotope-labeled isotope emission source inventory, combined with a preset meteorological field and initial boundary conditions, an atmospheric chemical transport model is driven to determine the molar concentrations of reactants and products before and after a chemical reaction process within the current master time step, as well as the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step. Based on the molar concentrations of reactants and products before and after the chemical reaction process within the current master time step, and the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step, determine the comprehensive apparent isotopic fractionation coefficients from reactants to products and the total reaction ratio within the current master time step during the chemical reaction process. When the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is divided into multiple sub-time steps. Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process within the current sub-time step are determined.

[0075] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0076] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, characterized in that, include: Based on the isotopic fingerprint source spectrum library of atmospheric chemical species, construct a model-driven multi-nucleotope labeling isotopic emission source inventory. Using the model-driven multi-nucleotope-labeled isotope emission source inventory, combined with a preset meteorological field and initial boundary conditions, an atmospheric chemical transport model is driven to determine the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, as well as the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step. Based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step, the comprehensive apparent isotopic fractionation coefficient from reactants to products and the total reaction ratio within the current main time step are determined during the chemical reaction process within the current main time step. When the total reaction ratio within the current main time step is greater than a preset threshold, the current main time step is time-divided to obtain multiple sub-time steps. Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the current sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process within the current sub-time step are determined.

2. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 1, characterized in that, Determining the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current master time step includes: Obtain the net change in the molar concentration of the products under different reaction pathways within the current main time step; Based on the net change, the relative conversion rate of the products in each reaction pathway is obtained.

3. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 1 or 2, characterized in that, The determination of the comprehensive apparent isotopic fractionation coefficient of reactants to products and the total reaction ratio within the current main time step, based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction pathways within the current main time step, includes: Based on the molar concentration of reactants before and after the chemical reaction process within the current main time step, the remaining proportion of reactants during the chemical reaction process within the current main time step is obtained. Based on the remaining proportion, the total reaction proportion within the current main time step is obtained; Based on the relative conversion rates of products under different reaction pathways in the chemical reaction process within the current master time step, and the isotopic fractionation coefficients of isotopes under different reaction pathways, the comprehensive apparent isotopic fractionation coefficients from reactants to products in the chemical reaction process within the current master time step are obtained.

4. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 1, characterized in that, Within the current sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentrations of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentrations and isotopic ratios of each isotope in the reactants and products after the chemical reaction process in the current sub-time step are determined, including: Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current sub-time step is obtained by taking into account the comprehensive apparent isotope fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. Based on the isotopic material balance relationship, according to the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratio of reactants and products in the current sub-time step, the change in molar concentration of each isotope after the chemical reaction process in the current sub-time step is obtained. Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, determine the molar concentration and isotope ratio of each isotope in the pre-mixed reactants after the chemical reaction process within the current sub-time step. Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, determine the molar concentration and isotope ratio of each isotope in the product after the chemical reaction process within the current sub-time step. Based on the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step is obtained.

5. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 4, characterized in that, The method, based on the Rayleigh fractionation formula, obtains the isotopic ratio of reactants and products in the current sub-time step by considering the comprehensive apparent isotopic fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step, including: Based on the Rayleigh fractionation formula, the isotope ratio of reactants and products in the current sub-time step is obtained by using the following calculation formula based on the comprehensive apparent isotopic fractionation coefficient and the molar concentration of reactants after the chemical reaction process in the previous sub-time step. ； ； ； in, and Each represents the previous time step. isubstep -1 Internal reactants Medium and heavy isotopes and light isotopes The molar concentration of the substance; Reactants within the previous time step isotope ratios; and These are the current sub-time steps. isubstep Internal reactants and products P isotope ratios; The reactants in the chemical reaction process within the current master time step To the product P The overall apparent isotopic fractionation coefficient, The reactants in the chemical reaction process within the current master time step The remaining proportion, This represents the proportion of the total reaction within the current master time step.

6. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 5, characterized in that, Based on isotopic equilibrium, and according to the molar concentrations of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratios of reactants and products in the current sub-time step, the change in molar concentration of each isotope after the chemical reaction process in the current sub-time step is obtained, including: Based on the isotopic material balance relationship, the following calculation formula is used to obtain the change in the concentration of each isotope after the chemical reaction process in the current sub-time step, according to the molar concentration of reactants and products after the chemical reaction process in the previous sub-time step and the isotopic ratio of reactants and products in the current sub-time step. = / ； ； in, and These represent the current sub-time step during the chemical reaction process. isubstep internal heavy isotope and light isotopes The change in the molar concentration of the substance.

7. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 6, characterized in that, The determination of the molar concentration of each isotope in the pre-mixing reactants after the chemical reaction process within the current sub-time step, based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, includes: Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, the molar concentration of each isotope in the pre-mixed reactants after the chemical reaction process within the current sub-time step is determined using the following calculation formula. ； ； in, and These are the current sub-time steps. isubstep Mixed pre-reactants Medium and heavy isotopes and light isotopes The molar concentration of a substance.

8. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 7, characterized in that, The determination of the molar concentration of each isotope in the product after the chemical reaction process within the current sub-time step, based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, includes: Based on the change in the molar concentration of each isotope after the chemical reaction process within the current sub-time step, the molar concentration of each isotope in the product after the chemical reaction process within the current sub-time step is determined using the following calculation formula. ； ； in, and Each represents the previous time step. isubstep -1 and the current sub-time step isubstep Products P Medium and heavy isotopes The molar concentration of the substance; and Each represents the previous time step. isubstep -1 and the current sub-time step isubstep Products P medium light isotope The molar concentration of a substance.

9. The method for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models according to claim 8, characterized in that, The process of obtaining the concentration of reactants after mixing in the chemical reaction process within the current sub-time step based on the molar concentration of reactants before mixing and the molar concentration of different isotopes in freshly mixed reactants within the sub-time step includes: Based on the molar concentration of the reactants before mixing after the chemical reaction process within the current sub-time step and the molar concentration of different isotopes in the freshly mixed reactants within the sub-time step, the molar concentration of the reactants after mixing during the chemical reaction process within the current sub-time step is obtained through the following calculation formula. ； ； in, and The reactants after mixing are respectively the current sub-time step (isubstep). Medium and heavy isotopes and light isotopes The molar concentration of the substance; and Freshly mixed reactants within sub-time steps Medium and heavy isotopes and light isotopes The molar concentration of a substance.

10. A device for improving the accuracy of isotope fractionation simulation in atmospheric chemical transport models, characterized in that, include: A module is built to construct an isotopic emission source inventory that conforms to model-driven multi-nucleotope labeling based on an isotopic fingerprint source library of atmospheric chemical species. The first determining module is used to drive an atmospheric chemical transport model based on the multi-nucleotope-labeled isotope emission source inventory driven by the conforming mode, combined with a preset meteorological field and initial boundary conditions, to determine the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and to determine the relative conversion rates of products under different reaction pathways during the chemical reaction process within the current main time step. The second determining module is used to determine the comprehensive apparent isotopic fractionation coefficient of reactants to products and the total reaction ratio within the current main time step based on the molar concentrations of reactants and products before and after the chemical reaction process within the current main time step, and the relative conversion rates of products under different reaction paths during the chemical reaction process within the current main time step. The partitioning module is used to divide the current main time step into multiple sub-time steps when the total reaction ratio within the current main time step is greater than a preset threshold. The third determining module is used to determine, within the current sub-time step, the concentration of each isotope in the reactants and products after the chemical reaction process in the previous sub-time step, based on the comprehensive apparent isotopic fractionation coefficient, the molar concentration of reactants and products after the chemical reaction process in the previous sub-time step, and the molar concentration of different isotopes in the freshly mixed reactants in the current sub-time step, and the molar concentration of each isotope in the reactants after the chemical reaction process in the current sub-time step.

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