Improved Method for Simulating Particulates Based on a High-Resolution Earth System Model

Abstract

The present invention provides an improved method for simulating particulate matter based on a high-resolution Earth system model. Based on the high-resolution Earth system model, an aerosol thermodynamics model is coupled into the original aerosol module to achieve the simulation of nitrate aerosols, etc. The calculation parameters of the nitric acid gas mass transfer coefficient are adjusted to reduce the simulation deviation of nitrate aerosols and improve the simulation ability of particulate matter concentration. By coupling and adding an aerosol thermodynamics model into the Earth system model, the physical and chemical mechanisms of the model aerosol are enriched, and the simulation of nitrate aerosols is realized, providing an important tool for studying the global aerosol distribution, changes and environmental effects. Based on the high-resolution Earth system model, the simulation ability of the model for aerosols is improved, the simulation deviation of the model is reduced, and the credibility of air pollution prediction is enhanced. According to the difference in the absorption coefficient of nitric acid gas in mineral dust, the mass transfer coefficient of nitric acid gas with respect to dust particles is adjusted to correct the underestimation of nitrate aerosols by the model.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance computing, and more particularly, to an improved method for particulate matter simulation based on a high-resolution Earth system model. Background Art

[0002] With the development of supercomputers, it has become possible to simulate high-resolution Earth system models. Recently, we achieved the stable operation of atmospheric chemistry simulation of a high-resolution (based on the Community Earth System Model CESM; the atmospheric and land surface resolutions are approximately 25 km) Earth system model on a domestic many-core heterogeneous supercomputing platform, improving the simulation accuracy of ozone (CN117669201 B). Compared with ozone, the composition and chemical mechanism of particulate matter are more complex, and the chemical mechanism of the Earth system model for particulate matter simulation is not yet perfect. For example, the atmospheric module (CAM-chem) of the Earth system model does not consider the aerosol thermodynamic process and cannot simulate nitrate aerosols, increasing the uncertainty in the assessment of aerosol concentration and its climate effects. Therefore, this patent couples an aerosol thermodynamic model in the Earth system model to improve the atmospheric chemical mechanism and enhance the aerosol simulation ability.

[0003] In addition, with the improvement of spatial resolution and the coupling of the aerosol thermodynamic model, there are still other problems in the model. On the one hand, the aerosol thermodynamic model realizes the gas-particle partitioning process by calculating the dynamic mass transfer coefficients of meteorological species in different particle size segments. Among them, HNO3 gas is treated specially because its absorption coefficient on the surface of dust particles is much lower than that of other particles. However, the absorption coefficient value set by the model for the absorption of nitric acid gas on dust particles is 1.1×10 -3 (the experimental range is between 0.1×10 -3 and 0.21), and the selected coefficient value is too low, resulting in the model underestimating the concentration level of nitrate aerosols to a certain extent. Coupled with the enhanced dust emissions caused by the improvement of the model resolution, the uncertainty in the simulation of nitrate aerosols is exacerbated. Therefore, on the basis of improving the model resolution and coupling the thermodynamic model, this patent will continue to adjust the dust emission coefficient to enhance the rationality of dust emission simulation in the high-resolution model. Furthermore, the absorption coefficient of nitric acid gas will be corrected to optimize the simulation of nitrate aerosols in the model. Summary of the Invention

[0004] To make up for the deficiencies of the prior art, the present invention provides an improved method for simulating particulate matter and its components based on a high-resolution Earth system model. Based on the high-resolution Earth system model, an aerosol thermodynamic model is coupled in the original aerosol module to achieve the simulation of nitrate aerosols and the improvement of the simulation of other aerosols. The calculation parameters of the nitric acid gas mass transfer coefficient are adjusted to reduce the simulation deviation of nitrate aerosols and improve the simulation ability of particulate matter concentration.

[0005] The present invention is realized through the following technical solutions: An improved method for particulate matter simulation based on a high-resolution Earth system model, specifically including the following steps:

[0006] Step S1: Coupling the aerosol thermodynamic model: In the Earth system model, the aerosol simulation uses the four-mode aerosol module MAM4, including the Aitken nuclear mode, the accumulation mode, the coarse mode, and primary carbon; coupling the aerosol thermodynamic model MOSAIC into the aerosol module MAM4. The existing aerosol species include sulfate aerosol, black carbon aerosol, dust aerosol, sea salt aerosol, primary organic aerosol, and secondary organic aerosol; on this basis, adding new species including nitrate NO3 - , ammonium salt NH4 + , sodium Na + , chlorine Cl - , calcium Ca 2+ , carbonate CO3 2- Insert the relevant new species into the default parameter list (namelist) file, the initial definition script of aerosol basic parameters (modal_aero_data.F90), the aerosol concentration calculation and update file (sox_cldaero_mod.F90), and the calculation scripts of sea salt and dust aerosols.

[0007] Step S2: Preparation of model simulation conditions: The input conditions in the model use high-resolution data, including anthropogenic source emission inventories, biomass burning sources, and meteorological forcing fields; among them, the anthropogenic source emission inventory uses the 0.1° global anthropogenic source emission inventory (CAMS-GLOB-ANT) released by the Copernicus Detection Service Center (CAMS), the biomass burning source uses the 0.1° fire emission inventory (FINN) released by the National Center for Atmospheric Research (NCAR) in the United States, and the climate forcing field uses the reanalysis data of the global terrestrial actual evapotranspiration dataset (MERRA-2).

[0008] Step S3: Adjustment of dust emission flux: Dust emission is highly sensitive to the model resolution. After improving the resolution, it is necessary to make targeted adjustments using the dust emission factor so that the simulated global dust aerosol optical depth is relatively reasonable. The dust emission flux calculation formula is as follows:

[0009] (1)

[0010] Among them, cflx represents the dust emission flux, idust represents the dust of a certain particle size segment, ndust is the total number of dust particle size segments, dust_in represents the dust emission obtained through land surface model simulation, dust_scl is the dust emission distribution coefficient,soil_erod is the soil erosion ability, soil_erod_fact is the dust emission adjustment factor;

[0011] Step S4, Adjustment of the key coefficient of HNO3 gas: In the model, the mass transfer coefficient of HNO3 in mineral dust is calculated as follows:

[0012] (2)

[0013] In the model, the absorption coefficient ( γ ) takes the value of 0.0011;

[0014] Step S5, The model will output aerosol, gas concentration, and meteorological data at different time scales with high resolution as needed. Write scripts based on NCL to batch process the output results and save them as NetCDF files; for aerosol species, it is necessary to convert their units based on data including temperature and pressure and compare them with the observed data; design scripts to achieve processing while outputting and save the results in an external Network Attached Storage (NAS) system;

[0015] Step S6, Visualize the obtained aerosol, gas, and meteorological data. Based on the NCL language, achieve the visualization of the output results; use the ESMF function of NCL to interpolate the output results and compare them with the observed data. The visualization schemes include time series plots, spatial distribution plots, and scatter plots;

[0016] Step S7, Model evaluation: The meteorological observation data used for evaluation is the ERA5 reanalysis data of the European Centre for Medium-Range Weather Forecasts, with a resolution of 0.25 degrees; for PM 2.5 and its component data in the United States and Europe, the European Monitoring and Evaluation Programme (EMEP) and the Interagency Monitoring of Protected Visual Environments (IMPROVE) are used respectively. The PM 2.5 concentration data in the Chinese region is from the China National Environmental Monitoring Centre, and the particulate matter component data uses the China Atmospheric Composition Near-Real-Time Tracking Dataset (TAP) released by Tsinghua University. Interpolate the observed results into a 0.25-degree grid and compare them with the model results, presenting them in the form of graphs and tables.

[0017] As a preferred solution, in step S1, the sum of the two aerosols of the new species sodium Na + and chlorine Cl - represents sea salt aerosol, and dust is composed of 2% calcium Ca 2+ , 3% carbonate CO3 2- and 95% of other inorganic substances that are not clearly labeled.

[0018] As a preferred solution, the dust emission adjustment factor in step S3 is 2.0.

[0019] As a preferred solution, the different time scales in step S5 include months, days, and hours.

[0020] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects compared with the prior art:

[0021] (1) By coupling and adding an aerosol thermodynamics model to the Earth system model, enriching the physical and chemical mechanisms of the model aerosol, and realizing the simulation of nitrate aerosols, it provides an important tool for studying the global aerosol distribution, changes, and environmental effects.

[0022] (2) Based on a high-resolution Earth system model, the simulation ability of the model for aerosols is improved, the simulation deviation of the model is reduced, and the credibility of air pollution prediction is enhanced.

[0023] (3) By selecting reasonable dust emission adjustment factors, the rationality of the model's simulation of dust emissions is improved.

[0024] (4) According to the difference in the absorption coefficient of nitric acid gas in mineral dust, the mass transfer coefficient of nitric acid gas with respect to dust particles is adjusted to correct the underestimation of nitrate aerosols by the model.

[0025] The additional aspects and advantages of the present invention will become apparent in the following description section or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0027] Figure 1 is a schematic diagram of the species composition of the model aerosol of the present invention;

[0028] Figure 2 is a diagram showing the simulation effect of PM in China, the United States, and European regions of the present invention 2.5 expressed in the form of a scatter plot. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to more clearly understand the above objects, features, and advantages of the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0030] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0031] The following is combined with Figures 1 to 2A specific description is given of the method for improving particulate matter simulation based on a high-resolution Earth system model in an embodiment of the present invention.

[0032] The present invention proposes a method for improving particulate matter simulation based on a high-resolution Earth system model. Based on high-resolution Earth system simulation, an aerosol thermodynamics model is coupled to enrich the chemical mechanism of particulate matter simulation. The dust emission factor is further corrected, the absorption coefficient of nitric acid gas is adjusted, and the refined simulation of particulate matter and its components is improved. The specific steps are as follows:

[0033] Step S1: Perform aerosol thermodynamics model coupling. There is a lack of aerosol thermodynamics processes in the Earth system model, and this process regulates the solid-gas phase distribution of aerosols, which is crucial for simulating aerosols generated from semi-volatile gases. The aerosol thermodynamics model is based on the principles of thermodynamics and phase equilibrium, considering diffusion, deposition, chemical processes, etc., and can approximately simulate the thermodynamic dynamic distribution process of aerosols. For the thermodynamics model, this patent adopts the MOSAIC (Model for Simulating Aerosol Interactions and Chemistry) model, which is maturely applied in common atmospheric chemistry models such as WRF-Chem. The model uses an adaptive time-splitting Euler method to handle the gas-phase particle distribution problem, effectively improving its own calculation efficiency while ensuring simulation accuracy, and is suitable for global-scale and high-resolution model simulations. The aerosol module in the Earth system model uses a four-mode aerosol module MAM4. The aerosol thermodynamics model MOSAIC is coupled to the aerosol module MAM4 in the Earth system model. MAM4 includes four modes: Aitken nuclei mode, accumulation mode, coarse mode, and primary carbon. Among them, the existing aerosol species include sulfate aerosols, black carbon aerosols, dust aerosols, sea salt aerosols, primary organic aerosols, and secondary organic aerosols. As Figure 1 shown, on the basis of the existing aerosol species, new species are added, including nitrate NO3 - 、ammonium salt NH4 + 、sodium Na + 、chlorine Cl - 、calcium Ca 2+ 、carbonate CO3 2- to the default parameter list (namelist) file, the initial definition script of aerosol basic parameters (modal_aero_data.F90), the aerosol concentration calculation and update file (sox_cldaero_mod.F90), and the sea salt and dust aerosol calculation script. For nitrate NO3 - Except for density, molecular weight, and hygroscopicity, other physical properties of the aerosol are set to be the same as those of sulfate aerosols.

[0034] Step S2, Preparation of model simulation conditions: In this patent, a relatively high spatial resolution is adopted in the model simulation process. Therefore, high-resolution data is also correspondingly used for various input conditions in the model, mainly including the atmospheric pollutant emission inventory, meteorological forcing fields, etc. Among them, the anthropogenic emission inventory uses the 0.1° global anthropogenic emission inventory (CAMS-GLOB-ANT) released by the Copernicus Atmosphere Monitoring Service (CAMS), the biomass burning source uses the 0.1° fire emission inventory (FINN) released by the National Center for Atmospheric Research (NCAR) in the United States, and the climate forcing field uses the reanalysis data of the global land actual evapotranspiration dataset (MERRA-2).

[0035] Step S3, Adjustment of dust emission flux: Dust emission is highly sensitive to the model resolution. After increasing the resolution, it is necessary to make targeted adjustments using the dust emission factor so that the simulated global dust aerosol optical depth is relatively reasonable. The formula for calculating the dust emission flux is as follows:

[0036] (1)

[0037] Wherein, cflx represents the dust emission flux, idust represents the dust of a certain particle size segment, ndust is the total number of dust particle size segments, dust_in represents the dust emission amount obtained through land surface model simulation, dust_scl is the dust emission distribution coefficient, soil_erod is the soil erosion ability, soil_erod_fact is the dust emission adjustment factor; increasing the model resolution often leads to an increase in the dust emission amount, and the setting of the adjustment factor should be increased correspondingly (the low-resolution value is set to 0.7) to make the dust emission reasonable. Through testing in this patent, the dust emission adjustment factor is corrected to 2.0, thereby optimizing the simulation results of dust aerosol and improving the accuracy of the simulation results.

[0038] Step S4, Adjustment of the absorption factor of mineral dust: In the aerosol thermodynamic process, there are differences in the absorption coefficients ( γ ) of semi-volatile gases on different particle surfaces, which leads to relatively large differences in the calculation of the mass transfer coefficients ( α ) of semi-volatile gases between the gas phase / liquid phase and the solid phase. According to field observations, the absorption coefficient of HNO3 gas on the surface of mineral dust is about 1 - 3 orders of magnitude lower than that of other particles, and the condensation of HNO3 gas is one of the important sources of nitrate aerosol, which is crucial for accurately simulating nitrate aerosol. The calculation of the mass transfer coefficient of HNO3 in mineral dust in the model is as follows:

[0039] (2)

[0040] According to the literature, the absorption coefficient of nitric acid gas on dust particles ranges from 0.1×10 -3 to 0.21. In the model, the absorption coefficient ( γ ) takes a lower value (0.0011). This patent will set up sensitivity tests based on actual observations, and simulate and evaluate the nitrate aerosol concentration using different absorption coefficients (0.0011, 0.01, and 0.1) respectively. Finally, an appropriate absorption coefficient ( γ ) value will be selected to make the nitrate concentration relatively reasonable;

[0041] Step S5: The model will output aerosol, gas concentration, and meteorological data at different time scales (monthly, daily, hourly) with high resolution according to requirements. Write a script based on NCL to batch process the output results and save them as NetCDF files; for aerosol species, it is necessary to convert their units based on data including temperature and pressure for easy comparison with observational data; design a script to achieve processing while outputting, and save the results in an external network attached storage (NAS) system;

[0042] Step S6: Visualize the obtained aerosol, gas, and meteorological data. Based on the NCL language, a batch processing program is involved to achieve the visualization of the output results; use the ESMF function of NCL to interpolate the output results for easy comparison with observational data. The visualization scheme includes time series plots, spatial distribution plots, and scatter plots;

[0043] Step S7: Model evaluation: The meteorological observational data used for evaluation is the ERA5 reanalysis data of the European Centre for Medium-Range Weather Forecasts, with a resolution of 0.25 degrees; the PM 2.5 and its component data in the United States and Europe are from the European Monitoring and Evaluation Programme (EMEP) and the Interagency Monitoring of Protected Visual Environments (IMPROVE) respectively. The PM 2.5 concentration data in the Chinese region is from the China National Environmental Monitoring Centre, and the particulate matter component data uses the China Atmospheric Composition Near-Real-Time Tracking Dataset (TAP) released by Tsinghua University. Interpolate the observational results into a 0.25-degree grid and compare them with the model results, presenting them in the form of tables and figures.

[0044] As Figure 2 shown, the seasonal average PM 2.5The correlation between the observational and simulation results is presented in the form of a scatter plot. Here, the vertical axis represents the simulation results, and the horizontal axis represents the observational results. The dotted lines of different colors represent different test cases. Among them, green represents the results of low-resolution without optimization, blue represents the results of low-resolution after optimization (coupled thermodynamic model, adjusted dust emission and absorption coefficients), purple represents the results of high-resolution without optimization, and red represents the results after optimization (coupled thermodynamic model, adjusted dust emission and absorption coefficients). The average values of the observations and simulations are marked in the upper left corner, and the correlation and slope results of different simulation results are also marked. Generally speaking, through optimization measures such as coupling the thermodynamic model, increasing the model resolution, and parameter adjustment, the Earth System Model CESM has been greatly improved in simulating PM in China and Europe. 2.5 The simulation effect has been significantly improved, while the improvement effect is relatively less obvious in regions relatively less affected by inorganic aerosols such as nitrates (such as the United States).

[0045] In the description of the present invention, the term "a plurality of" means two or more, unless otherwise clearly defined. The orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention; terms such as "connection", "installation", and "fixation" should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", and "specific embodiments" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0047] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. An improved method for simulating particulate matter based on a high-resolution Earth system model, characterized in that , specifically including the following steps: Step S1, coupling aerosol thermodynamic model: aerosol simulation in the Earth system model uses the four-mode aerosol module MAM4, including four modes: Agen core membrane, accumulation mode, coarse mode and primary carbon; the aerosol thermodynamic model MOSAIC is coupled to the aerosol module MAM4, and the existing aerosol species include sulfate aerosol, black carbon aerosol, dust aerosol, sea salt aerosol, primary organic aerosol and secondary organic aerosol; on this basis, new species are added including nitrate NO3 - 、Ammonium salt NH4 + , sodium Na + , chlorine - Calcium 2+ 、Carbonate CO3 2- Insert the relevant new species into the default parameter list namelist file, the aerosol basic parameter initial definition script modal_aero_data.F90, the aerosol concentration calculation update file (sox_cldaero_mod.F90), and the sea salt and dust aerosol calculation scripts; Step S2, model simulation condition preparation: the input conditions in the model use high-resolution data, including anthropogenic emission inventory, biomass burning source and meteorological forcing field; the anthropogenic emission inventory uses the 0.1° global anthropogenic emission inventory CAMS-GLOB-ANT released by the Copernicus Observation Service CAMS, the biomass burning source uses the 0.1° fire emission inventory FINN released by the National Center for Atmospheric Research NCAR, and the climate forcing field uses the reanalysis data of the global land actual evapotranspiration dataset MERRA-2; Step S3, dust emission flux adjustment: Dust emission is highly sensitive to model resolution. After improving the resolution, the dust emission factor needs to be used for targeted adjustment. After the adjustment, the simulated global dust aerosol optical thickness is relatively reasonable. The dust emission flux calculation formula is as follows: （1） in, cflx represents the dust emission flux, idust Indicates dust particles of a certain size range. ndust is the total number of dust particle size segments, dust_in represents the dust emission simulated by the land surface model, dust_scl is the dust emission distribution coefficient, soil_erod The soil erosion capacity, soil_erod_fact is the dust emission adjustment factor; Step S4, HNO3 gas key coefficient adjustment: The mass transfer coefficient of HNO3 in mineral dust in the model is calculated as follows: （2） Absorption coefficient in mode γ The value of is 0.0011; Step S5: The model will output high-resolution aerosol, gas concentration and meteorological data of different time scales as needed. The script will be written based on NCL to batch process the output results and save them as NetCDF files. For aerosol species, it is necessary to convert their units based on data including temperature and air pressure and compare them with the observed data. The script is designed to realize simultaneous output and processing, and the results are saved in an external network attached storage NAS system. Step S6: Visualize the obtained aerosol, gas and meteorological data, and realize the visualization of the output results based on the NCL language; use the ESMF function of NCL to interpolate the output results and compare them with the observed data. The visualization scheme includes time series diagram, spatial distribution diagram and scatter diagram; Step S7, model evaluation: The meteorological observation data used for evaluation are ERA5 reanalysis data of the European Centre for Medium-Range Weather Forecasts, with a resolution of 0.25 degrees; PM 2.5 The data of PM and its components were respectively obtained from the European Monitoring and Evaluation Program (EMEP) and the Inter-Agency Monitoring of the Protected Visual Environment (IMPROVE). 2.5 The concentration data comes from the China National Environmental Monitoring Center, and the particulate matter component data uses the China Atmospheric Composition Near-Real-Time Tracking Dataset TAP released by Tsinghua University. The observation results are interpolated to a 0.25 degree grid and compared with the model results and presented in the form of graphs and tables.

2. The improved method for simulating particulate matter based on a high-resolution earth system model according to claim 1, characterized in that , the new species sodium Na in step S1 + , chlorine - The sum of the two aerosols represents sea salt aerosol, while dust is composed of 2% calcium Ca 2+ , 3% carbonate CO3 2- and 95% of other inorganic substances not explicitly specified.

3. The improved method for simulating particulate matter based on a high-resolution earth system model according to claim 1 is characterized in that , the dust emission adjustment factor is 2.

0.

4. The improved method for simulating particulate matter based on a high-resolution earth system model according to claim 3 is characterized in that , the absorption coefficient is corrected to 10 -2 .

5. The improved method for simulating particulate matter based on a high-resolution earth system model according to claim 1 is characterized in that ,The different time scales in the step S4 include months, days and hours.

Images