Process model system for simulating HONO flux of ecological system and construction method of process model system

Abstract

The invention provides an ecosystem HONO flux simulation process model system and a construction method thereof, and relates to the technical field of a soil nitrogen cycle process. Based on a current version of hydrological-biogeochemical process model (CNMM-DNDC), a scientific process simulation mechanism of HONO generation and consumption in soil and HONO exchange in a soil-plant-atmosphere interface is designed on a source code level, and the newly added process source code is seamlessly coupled with a soil nitrogen cycle process module of the current version of CNMM-DNDC model. An improved CNMM-DNDC model execution program is obtained, and the blank that an existing biogeochemical process model does not have the function of generating and consuming the HONO in the soil and the function of simulating transmission of the HONO in the soil-plant-atmosphere interface is filled.

Description

Technical Field

[0001] The invention relates to the technical field of soil nitrogen cycle processes, and in particular to a process model system for HONO flux simulation of an ecosystem and a construction method thereof. Background Art

[0002] Human survival and food security have long relied on the input of large amounts of nitrogen fertilizers into agricultural ecosystems. However, the widespread and excessive use of nitrogen fertilizers has led to a sharp increase in the emission of reactive nitrogen (Nr) gases from the soil, including ammonia (NH3), gaseous nitrite (HONO), nitric oxide (NO), nitrous oxide (N2O) and nitrogen dioxide (NO2), causing a serious imbalance in the soil nitrogen cycle and the nitrogen balance between soil, plants and the atmosphere, leading to a series of severe environmental problems such as eutrophication of water bodies, acidification of water bodies, global warming and air pollution that threaten human health and the ecosystems on which they depend for survival.

[0003] HONO is one of the important precursors of the strong oxidant hydroxyl radical (OH) in the atmosphere. Its daytime photolysis can contribute up to more than 60% to OH radicals, playing an important role in the removal of atmospheric pollutants and the formation of secondary pollutants. In addition, HONO can also harm human health. It not only damages human mucous membranes and lung function, but also acts as a precursor of carcinogens (nitroamines) in human lungs. HONO concentrations are low in clean areas such as rural areas (about 1 ppbv), but can be as high as 8 ppbv in heavily polluted areas such as cities. Normally, HONO accumulates continuously at night, and its concentration drops to a minimum (about 0.001 ppbv) at noon or in the afternoon due to daytime photolysis. Recent studies have found that higher HONO concentrations are observed even during the day. The only known important gas-phase source of HONO is the homogeneous reaction between NO and OH radicals. The main sink during the day is the photolysis of HONO to produce NO and OH radicals. The above-known homogeneous reaction between NO and OH radicals is not sufficient to explain the high daytime concentration levels and diurnal variation curves of HONO observed in the atmosphere, indicating that there are still unknown important sources and mechanisms of HONO.

[0004] Studies have reported that soil microbial activities in ecosystems, especially in fertilized farmland, will emit a large amount of Nr gas into the atmosphere. Soil is an important source of atmospheric HONO. Domestic and foreign research on soil HONO emissions has also developed from laboratory measurements to more direct field in situ measurements. However, it is difficult to achieve simultaneous quantification and research on the characteristics, generation mechanisms and interrelationships of soil Nr emissions in typical ecosystems under complex natural conditions or human activities only through field in situ experiments.

[0005] The combination of process model simulation and advanced experimental measurement methods may make up for the above-mentioned shortcomings of field in-situ measurements, help clarify the synchronous emission mechanism of soil Nr in typical ecosystems under different environmental conditions and human activities in various regions, and realize accurate quantification of its characteristics. Among them, the model based on the hydrological-biogeochemical process model (CNMM-DNDC) is a three-dimensional model that can simulate the interaction of carbon-nitrogen-water cycles. This model seamlessly couples the core carbon and nitrogen biogeochemical processes of the DNDC model, including organic matter decomposition, nitrification, denitrification and fermentation, to the distributed eco-hydrological process framework (DHSVM, an internationally open source distributed three-dimensional hydrological model) of the CNMM (watershed nutrient management model), thereby realizing a three-dimensional simulation of the carbon-nitrogen-water interaction process of various ecosystems under different conditions with high time (3 hours), high space (customized 1 meter to 1 kilometer) and high process (chemical reactions of major carbon and nitrogen conversion and physical migration pathways of gas and liquid components) resolution. Since the first version of CNMM-DNDC was published in 2018, the model has undergone many internal scientific process improvements and simulation function expansions, completing the model's detailed depiction of the fully coupled carbon, nitrogen, phosphorus and water cycles in terrestrial ecosystems. These model function improvements include the introduction of freeze-thaw mechanisms, the creation of a new simulation mechanism for the impact of aluminum metabolism of Theaceae plants on soil pH in tea gardens, the construction of a new simulation mechanism for ammonia volatilization in surface aquatic ecosystems, the improvement of the first-order kinetic simulation mechanism for ammonia volatilization in dry land, and the introduction of a simulation mechanism for soil erosion and particulate carbon, nitrogen and phosphorus migration. To date, the current version of CNMM-DNDC has passed extensive comprehensive testing and verification of ecosystems in different bioclimatic zones from tropical to cold temperate zones, and has carried out simulation tests or practical applications of multiple sustainable development goal characterization variables related to ecosystem carbon and nitrogen cycles in 15 regions or river basins, demonstrating good universality and reliability in simulating carbon and nitrogen water cycle processes such as soil physical and chemical conditions, ecosystem productivity, evapotranspiration, soil erosion, hydraulic nitrogen loss, carbon and nitrogen greenhouse gas and pollution gas emissions in typical ecosystems of different bioclimatic zones. It has passed the reliability verification of in-situ test data of Nr emissions in different ecosystem types, and realized the reliability verification of CNMM-DNDC simulation of NH3, NO and / or N2O emissions in various typical ecosystems such as woodlands, wetlands and farmlands based on NO and / or N2O emission flux data.

[0006] In recent years, both field in-situ tests and the independent carbon and nitrogen biogeochemical process model CNMM-DNDC have made breakthrough progress in the soil Nr emission mechanism and its interrelationship. 15In-situ tracing of N isotopes and in-situ determination of soil HONO have achieved a number of technical breakthroughs and progress in mechanism research, and the autonomous carbon and nitrogen biogeochemical process model CNMM-DNDC has achieved high-resolution synchronous simulation of Nr (including NH3, NO and N2O) emissions from typical ecosystems. However, the existing CNMM-DNDC models do not yet have the simulation function of HONO generation and consumption in the soil and its transmission at the soil-plant-atmosphere interface, which is an urgent problem to be solved in the field of ecosystem nitrogen cycle and atmospheric chemistry research. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a process model system for HONO flux simulation of an ecosystem and a construction method thereof. The process model system for HONO flux simulation of an ecosystem constructed by the present invention (improved version CNMM-DNDC) has the functions of simulating the production and consumption of HONO in soil and the transmission of HONO at the soil-plant-atmosphere interface.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for constructing a process model system for HONO flux simulation of an ecosystem, comprising the following steps: Testing the concentration of HONO in the atmosphere, and obtaining the HONO emission flux from the soil to the atmosphere according to Formula I based on the concentration of HONO in the atmosphere; Formula I; In Formula I, F s is the HONO emission flux from soil to the atmosphere, in kg·N·ha -1 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 .

[0009] Testing the concentration of HONO in the atmosphere, and obtaining the absorption flux of HONO by plants per unit surface area according to Formula II based on the concentration of HONO in the atmosphere; Formula II; In Formula II, U p is the HONO absorption flux of plants per unit surface area, in kg·N·ha-1 ·h -1 ; f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO; f m is the effect function of surface soil moisture on plant leaf absorption of HONO; K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; LAI is the leaf area index of plants, using the dynamic simulation value of each simulation step of CNMM-DNDC; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; T 0 is 273.15K; P 0 is 1013hPa; P is the atmospheric pressure, in hPa; The reference flux of HONO emitted per unit plant leaf area is tested, and the emission flux of HONO by plants per unit surface area is obtained according to Formula III based on the reference flux of HONO emitted per unit plant leaf area; Formula III; In formula III, F p is the HONO emission flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface; f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; f RH is the effect function of environmental relative humidity on the HONO production rate on the plant leaf surface; F ref is the reference flux of HONO emission per unit plant leaf area, in kg·N·m -2 LAI·h -1 ; LAI is the plant leaf area index, using the dynamic simulation value of each simulation step of CNMM-DNDC; The net exchange flux of HONO between the soil-plant system and the atmosphere is obtained according to Formula IV from the HONO emission flux from the soil to the atmosphere, the HONO absorption flux of the plants per unit surface area, and the HONO emission flux of the plants per unit surface area; Formula IV; In Formula IV, F HONO is the net HONO exchange flux between the soil-plant system and the atmosphere, in kg·N·ha -1 ·h -1 .

[0010] Preferably, the method for obtaining the HONO concentration in the surface soil gas phase comprises the following steps: The dynamic simulation results of the CNMM-DNDC model are used to obtain the l H in soil solution + and NO2 - concentration; By the said l H in soil solution + and NO2 - The concentration of l The concentration of HNO2 in the soil solution of the layer; Formula 1; In formula 1, [HNO2] aq(l) For the l The concentration of HNO2 in the soil solution of the layer, in mol·L -1 ; k a(l) is the dissociation equilibrium constant of HNO2; [H + ] l For the l H in soil solution + The concentration is in mol·L -1 ; [NO2 - ] l For the l NO2 in soil solution - The concentration is in mol·L -1 ; From formula 2, we can get l The equilibrium partial pressure of HONO in the soil gas phase; Formula 2; In formula 2, For the l The equilibrium partial pressure of HONO in the soil gas phase is in Pa; H n(l) For HNO2 l Henry constant under the reaction environment conditions of the soil layer, unit is L·Pa·mol -1 ; According to Formula 1 and Formula 2, Formula 3 is obtained; Formula 3; By the said l The equilibrium partial pressure of HONO in the soil gas phase is obtained according to Eq. l HONO concentration in the soil gas phase of the layer; Formula 4; In formula 4, [HONO] g(l) For the l HONO concentration in the soil gas phase, unit: mol·L -1 ; T s(l) For the l Layer soil temperature, in K; R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 ; By the said l Layer and ( l The HONO concentration in the soil gas phase of the -1 layer is obtained according to Equation 5. l HONO in the soil gas phase moves to the first ( l -1) Diffusion rate of soil layer; Formula 5; In formula 5, dF (l) For HONO from soil l Layer to the first ( l -1) Diffusion rate of the layer; [HONO] g(l) For the l HONO concentration in the soil gas phase, in mol·L -1 ; [HONO] g(l-1) For the first ( l -1) HONO concentration in the soil gas phase, unit: mol·L -1 ; From the soil by HONO l Layer to the first ( l -1) layer diffusion rate, after at least 5 iterations, calculated layer by layer until the diffusion rate of HONO from the second soil layer to the surface layer is calculated. The current concentration of HONO in the surface soil gas phase is obtained according to Formula 6 based on the above diffusion rate of HONO from the second soil layer to the surface layer and the original HONO concentration in the surface soil gas phase; Formula 6; In formula 6, [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; [HONO] g(1)is the original concentration of HONO in the surface soil gas phase, in mol·L -1 ; dF 1 is the diffusion rate of HONO from the second soil layer to the surface layer.

[0011] Preferably, the method for obtaining the dissociation equilibrium constant of HNO2 comprises the following steps: l The dissociation equilibrium constant is obtained according to Formula 7; Formula 7; In formula 7, k a(l) is the dissociation equilibrium constant of HNO2; T s(l) For the l Layer soil temperature, in K; K a(298K) is the dissociation equilibrium constant of HNO2 at room temperature; Δ H HNO2 is the standard molar enthalpy of formation of HNO2 at room temperature and pressure, in kJ·mol -1 ; R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 ; The HNO2 in soil l The method for obtaining the Henry constant under the layer reaction environment conditions comprises the following steps: l The soil temperature of the first layer is obtained according to formula 8. l Henry constant for the soil layer under the reaction environment conditions; Formula 8; In formula 8, H n(l) HNO2 in soil l Henry constant under the environmental conditions of the layer reaction, unit is L·Pa·mol -1 ; T s(l) For the l Layer soil temperature, in K; H n(298K) is the Henry constant for the equilibrium distribution of HNO2 between the soil water phase and the gas phase at room temperature, in L·Pa·mol -1 ; Δ H HONO is the standard molar formation enthalpy of HONO from the soil liquid phase to the gas phase at room temperature and pressure, in kJ·mol -1 ; R is the universal gas constant.

[0012] Preferably, the method for obtaining the gas transmission rate of HONO from soil to atmosphere comprises the following steps: From the aerodynamic damping, quasi-laminar layer damping and surface damping, the gas transmission rate of HONO from soil to atmosphere is obtained according to Equation 9; Formula 9; In formula 9, v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 ; R a is the aerodynamic damping, in s·m -1 ; R b is the quasi-laminar layer damping, unit is s·m -1 ; R s is the aerodynamic damping, in s·m -1 ; The method for obtaining the aerodynamic damping comprises the following steps: measuring a reference height of the HONO flux, and obtaining the aerodynamic damping according to equation 10 based on the reference height of the HONO flux and the surface roughness height; Formula 10; In formula 10, R a is the aerodynamic damping, in s·m -1 ; z 0 is the surface roughness height, in m; z ref is the reference height for measuring HONO flux, in meters; u is the friction wind speed, in m·s -1 ; K is the Karman constant, its value is 0.4; The method for obtaining the quasi-laminar layer damping comprises the following steps: obtaining the quasi-laminar layer damping according to Formula 11 from the Schmidt number, the Prandtl number, the Karman constant and the friction wind speed; Formula 11; In formula 11, R b is the quasi-laminar layer damping, unit is s·m -1 ; S c is the Schmidt number, its value is 1.07; P r is the Prandtl number, which is 0.72; K is the Karman constant, its value is 0.4; u is the friction wind speed, in m·s -1 ; The method for obtaining the surface damping comprises the following steps: obtaining the surface damping from the surface soil moisture according to equation 12; Formula 12; In formula 12, R s is the surface damping, in s·m -1 ; M s(1) is the surface soil moisture, in v / v.

[0013] Preferably, the method for obtaining the friction wind speed comprises the following steps: The wind speed at the reference height of the HONO flux test is measured, and the friction wind speed is obtained from the wind speed at the reference height and the wind speed at the surface roughness height according to Formula 13: Formula 13; In formula 13, u is the friction wind speed, in m·s -1 ; u ref is the wind speed at the reference height, in m·s -1 ; u 0 is the wind speed at the surface roughness height, in m·s -1 ; z 0 is the surface roughness height, in m; z ref is the reference height, in m; K is the Karman constant, its value is 0.4; The method for obtaining the surface roughness height comprises the following steps: The average vegetation height is obtained from the calculation results of the plant growth module of CNMM-DNDC, and the surface roughness height is obtained from the average vegetation height according to formula 14: Formula 14; In formula 14, z 0 is the surface roughness height, in m; H p is the average height of vegetation, in meters.

[0014] Preferably, the method for obtaining the influence function of HONO absorption per unit plant leaf area comprises the following steps: The ambient temperature at a height of 2 m above the ground was tested, and the rate constant of HONO absorption per unit plant leaf area was obtained from the ambient temperature according to Formula 15: Formula 15; In formula 15, K pis the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; T a It is the ambient temperature at a height of 2m from the ground, in K.

[0015] Preferably, the method for obtaining the influence function of the plant leaf area index on the absorption of HONO by plant leaves comprises the following steps: The leaf area index is obtained from the calculation result of the plant growth module of CNMM-DNDC, and the influence function of the plant leaf area index on the absorption of HONO by the plant leaves is obtained according to Formula 16 from the model default value of the maximum leaf area index, the leaf area index and the maximum leaf area index; Formula 16; In formula 16, f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO, LAI is plant leaf area index, LAI max is the maximum leaf area index.

[0016] Preferably, the method for obtaining the influence function of surface soil moisture on plant leaf absorption of HONO comprises the following steps: The surface soil moisture is obtained from the calculation results of the soil environment module of CNMM-DNDC, and the model input parameters of the surface soil porosity are used. According to the surface soil moisture and the surface soil porosity, the influence function of the surface soil moisture on the absorption of HONO by plant leaves is obtained according to Formula 17; Formula 17; In formula 17, f m is the effect function of surface soil moisture on plant leaf absorption of HONO; M s(1) is the surface soil moisture, unit v / v; PORE s(1) It is the porosity of surface soil, unit is v / v.

[0017] Preferably, the method for obtaining the influence function of the ambient temperature on the HONO production rate on the plant leaf surface comprises the following steps: The ambient temperature at a height of 2 m above the ground is tested, and the influence function of the ambient temperature on the HONO generation rate on the plant leaf surface is obtained according to Formula 18. Formula 18; In formula 18, f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface; Ta is the ambient temperature at a height of 2m from the ground, in K; The method for obtaining the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the plant leaf surface comprises the following steps: Testing the NO2 concentration in the atmosphere, and obtaining the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the plant leaf surface according to Formula 19; Formula 19; In formula 19, f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; [NO2] a is the concentration of NO2 in the atmosphere, in mol·L -1 ; The method for obtaining the influence function of the relative humidity of the environment on the HONO production rate on the plant leaf surface comprises the following steps: The relative humidity of the testing environment is used to obtain the influence function of the relative humidity of the environment on the HONO production rate on the plant leaf surface according to Formula 20; Formula 20; In formula 20, f RH is the influence function of environmental relative humidity on the HONO production rate on the plant leaf surface; RH is the environmental relative humidity, the unit is %.

[0018] The present invention also provides a process model system for HONO flux simulation of an ecosystem obtained by the construction method described in the above technical solution.

[0019] The present invention is based on the current version of the hydrological-biogeochemical process model (CNMM-DNDC), and designs the scientific process simulation mechanism of HONO production and consumption in soil and HONO exchange at the soil-plant-atmosphere interface at the source code level, and seamlessly couples the newly added process and its source code program with the soil nitrogen cycle process of the current version of the CNMM-DNDC model, thereby obtaining an improved version of the CNMM-DNDC model execution program. The process model system for ecosystem HONO flux simulation constructed by the present invention (improved version CNMM-DNDC) has the function of simulating HONO production and consumption in soil and HONO exchange at the soil-plant-atmosphere interface, which fills the gap that the existing biogeochemical process model does not have the simulation function of HONO generation and consumption in soil and its transmission at the soil-plant-atmosphere interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The present invention adds a new soil HONO generation and elimination mechanism and emission and absorption process diagram based on the current version of CNMM-DNDC; Figure 2 This is a diagram of the simulation results of HONO emission flux under the process model system for ecosystem HONO flux simulation constructed by the present invention. DETAILED DESCRIPTION

[0021] The present invention provides a method for constructing a process model system for HONO flux simulation of an ecosystem, comprising the following steps: Testing the concentration of HONO in the atmosphere, and obtaining the HONO emission flux from the soil to the atmosphere according to Formula I based on the concentration of HONO in the atmosphere; Formula I; In Formula I, F s is the HONO emission flux from soil to the atmosphere, in kg·N·ha -1 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 ; Testing the concentration of HONO in the atmosphere, and obtaining the absorption flux of HONO by plants per unit surface area according to Formula II based on the concentration of HONO in the atmosphere; Formula II; In Formula II, U p is the HONO absorption flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO; f m is the effect function of surface soil moisture on plant leaf absorption of HONO; K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; LAI is the leaf area index of plants, using the dynamic simulation value of each simulation step of CNMM-DNDC; [HONO] ais the concentration of HONO in the atmosphere, in mol·L -1 ; T 0 is 273.15K; P 0 is 1013hPa; P is the atmospheric pressure, in hPa; The reference flux of HONO emitted per unit plant leaf area is tested, and the emission flux of HONO by plants per unit surface area is obtained according to Formula III based on the reference flux of HONO emitted per unit plant leaf area; Formula III; In formula III, F p is the HONO emission flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface; f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; f RH is the effect function of environmental relative humidity on the HONO production rate on the plant leaf surface; F ref is the reference flux of HONO emission per unit plant leaf area, in kg·N·m -2 LAI·h -1 ; LAI is the plant leaf area index, using the dynamic simulation value of each simulation step of CNMM-DNDC; The net exchange flux of HONO between the soil-plant system and the atmosphere is obtained according to Formula IV from the HONO emission flux from the soil to the atmosphere, the HONO absorption flux of the plants per unit surface area, and the HONO emission flux of the plants per unit surface area; Formula IV; In Formula IV, F HONO is the net exchange flux of HONO between the soil-plant system and the atmosphere, in kg·N·ha -1 ·h -1 .

[0022] The parameters used in the calculation formulas of the present invention and their meanings and sources are shown in Tables 1-2, wherein the values ​​calculated by this model are values ​​calculated by the process model system of the ecosystem HONO flux simulation constructed by the present invention, and the values ​​simulated by the original model are values ​​calculated by the current version of CNMM-DNDC.

[0023] Table 1 Parameters used in various calculation formulas and their meanings and sources

[0024] Table 2 Parameters used in each calculation formula and their meanings and sources

[0025] Next, we will construct the hydrogen ion (H + ) and nitrite nitrogen (NO2 - ) is explained by the liquid phase chemical dynamic equilibrium function.

[0026] Nitrite HNO2 is highly water-soluble and can undergo dissociation reactions in all layers of the soil to generate NO2 - and H + ions, but this is a reversible reaction, NO2 - and H + The ions can combine into HNO2 molecules (Reaction 1, ①), and the HNO2 molecules are distributed between the liquid phase and the gas phase in the soil pores (Reaction 1, ②). This reversible distribution process obeys Henry's law.

[0027] Reaction 1.

[0028] In the present invention, the l The method for obtaining the concentration of HNO2 in the soil solution of the first layer preferably comprises the following steps: obtaining the first layer of HNO2 from the dynamic simulation results of the CNMM-DNDC model; l H in soil solution + and NO2 - The concentration of l H in soil solution + and NO2 - The concentration of l The concentration of HNO2 in the soil solution of the layer; Formula 1; In formula 1, [HNO2] aq(l) For the l The concentration of HNO2 in the soil solution of the layer, in mol·L -1 ; k a(l) is the dissociation equilibrium constant of HNO2; [H + ] l For the l H in soil solution + The concentration is in mol·L -1 ; [NO2 - ] l For the l NO2 in soil solution- The concentration is in mol·L -1 .

[0029] The establishment of the HONO gas-liquid equilibrium function based on Henry's law is explained below.

[0030] Henry's law can be used to calculate the equilibrium distribution of HNO2 between the liquid phase and the gas phase in the soil pores of each soil layer.

[0031] According to the ideal gas state equation, l HONO concentration in the soil vapor phase ([HONO] g(l) ) can be used l Equilibrium partial pressure of HONO in the soil gas phase calculate.

[0032] In the present invention, the method for obtaining the HONO concentration in the surface soil gas phase preferably comprises the following steps: From formula 2, we can get l The equilibrium partial pressure of HONO in the soil gas phase; Formula 2; In formula 2, For the l The equilibrium partial pressure of HONO in the soil gas phase is in Pa; H n(l) For HNO2 l Henry constant under the reaction environment conditions of the soil layer, unit is L·Pa·mol -1 ; According to Formula 1 and Formula 2, Formula 3 is obtained; Formula 3; According to the ideal gas state equation, l The equilibrium partial pressure of HONO in the soil gas phase is obtained according to Equation 4. l HONO concentration in the soil gas phase of the layer; Formula 4; In formula 4, [HONO] g(l) For the l HONO concentration in the soil gas phase, unit: mol·L -1 ; T s(l) For the l Layer soil temperature, in K; R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 ; No. lThe HONO concentration in the gas phase of the first layer of soil can move between the soil layers through diffusion driven by the concentration gradient, and finally be released into the atmosphere through the soil surface. l Layer and ( l The HONO concentration in the soil gas phase of the -1 layer is obtained according to Equation 5. l HONO in the soil gas phase moves to the first ( l -1) Diffusion rate of soil layer; Formula 5; In formula 5, dF (l) For HONO from soil l Layer to the first ( l -1) Diffusion rate of the layer; [HONO] g(l) For the l HONO concentration in the soil gas phase, in mol·L -1 ; [HONO] g(l-1) For the first ( l -1) HONO concentration in the soil gas phase, unit: mol·L -1 .

[0033] From the soil by HONO l Layer to the first ( l -1) layer, after at least 5 iterations, calculated layer by layer until the diffusion rate of HONO from the second soil layer to the surface layer (first layer) is calculated. The current concentration of HONO in the surface soil gas phase is obtained according to Formula 6 based on the above diffusion rate of HONO from the second soil layer to the surface layer (first layer) and the original HONO concentration in the surface soil gas phase; Formula 6; In formula 6, [HONO] g(1) ' is the current concentration of HONO in the surface (1st layer) soil gas phase, in mol·L -1 ; [HONO] g(1) is the original concentration of HONO in the surface (first layer) soil gas phase, in mol·L -1 ; dF 1 is the diffusion rate of HONO from the second soil layer to the surface layer.

[0034] In the present invention, according to the Arrhenius empirical equation of the relationship between the chemical reaction rate constant and the temperature, H n(l) and k a(l) can be expressed as soil temperature T s(l) function.

[0035] In the present invention, the method for obtaining the dissociation equilibrium constant of HNO2 preferably comprises the following steps: l The dissociation equilibrium constant is obtained according to Formula 7; Formula 7; In formula 7, k a(l) is the dissociation equilibrium constant of HNO2; T s(l) For the l Layer soil temperature; K a(298K) is the dissociation equilibrium constant of HNO2 at room temperature; Δ H HNO2 is the standard molar enthalpy of formation of HNO2 dissociation at room temperature and pressure; R is the universal gas constant. In the present invention, the l The soil temperature of each layer is preferably the dynamic simulation value of each simulation step of CNMM-DNDC.

[0036] In the present invention, the HNO2 l Henry constant under environmental conditions of soil layer reaction H n(l) The method for obtaining the HNO2 preferably comprises the following steps: l The method for obtaining the Henry constant under the layer reaction environment conditions comprises the following steps: l The soil temperature of the first layer is obtained according to formula 8. l Henry constant for the soil layer under the reaction environment conditions; Formula 8; In formula 8, H n(l) HNO2 in soil l Henry constant under the environmental conditions of the layer reaction, unit is L·Pa·mol -1 ; T s(l) For the l Layer soil temperature, in K; H n(298K) is the Henry constant for the equilibrium distribution of HNO2 between the soil water phase and the gas phase at room temperature, in L·Pa·mol -1 ; Δ H HONO is the standard molar formation enthalpy of HONO from the soil liquid phase to the gas phase at room temperature and pressure, in kJ·mol -1 ; R is the universal gas constant. In the present invention, the lThe soil temperature of each layer is preferably the dynamic simulation value of each simulation step of CNMM-DNDC.

[0037] In the present invention, the K a(298K) Preferably 5.1×10 -4 , H n(298K) Preferably 2.08×10 -3 L.Pa.mol -1 , ΔH HNO2 Preferably -118.83 kJ·mol -1 , Δ H HONO Preferably 1423.5 kJ·mol -1 , R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 . The first l Soil temperature T s(l) The dynamic simulation value of each simulation step of CNMM-DNDC is adopted.

[0038] The following is an explanation of the process of constructing the vertical transport between soil layers based on the concentration gradient of HONO gas in the surface soil pores and the emission process function based on the concentration gradient of HONO in the surface soil pores and the atmosphere.

[0039] The present invention tests the concentration of HONO in the atmosphere, and obtains the HONO emission flux from the soil to the atmosphere according to Formula I from the concentration of HONO in the atmosphere; Formula I; In Formula I, F s is the HONO emission flux from soil to the atmosphere, in kg·N·ha -1 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 .

[0040] In the present invention, the [HONO] aIt is preferred to use the test data of HONO concentration in the atmosphere (with seasonal and daily dynamics) for setting. In the coupled simulation experiment of CNMM-DNDC and atmospheric chemical transport model, [HONO] a The set value is replaced by a dynamic simulated value provided by an air quality model or a field-measured atmospheric model.

[0041] In the present invention, the gas transmission rate ( v ) depends mainly on meteorological and soil conditions and can be calculated based on damping theory. The three main processes that limit the migration of HONO from the soil surface to the free atmosphere are, from bottom to top in space: (i) emission or deposition on the soil surface; (ii) migration in the quasi-laminar layer (a very thin layer of stagnant air near the soil surface); and (iii) turbulent transport between the top of the quasi-laminar layer and the free atmosphere. These three processes are controlled by surface damping ( R s )、quasi-laminar layer damping( R b ) and aerodynamic damping ( R a ) are connected in series to directly regulate the transport of HONO between soil and free atmosphere. v With total damping ( R a , R b and R s The sum of (see equation 9) is used to calculate the inverse of v The value is usually 0.01m·s -1 about.

[0042] In the present invention, the method for obtaining the gas transmission rate comprises the following steps: the gas transmission rate is obtained according to equation 9 from aerodynamic damping, quasi-laminar layer damping and surface damping: Formula 9; In formula 9, v is the gas transmission rate, in m·s -1 ; R a is the aerodynamic damping, in s·m -1 ; R b is the quasi-laminar layer damping, unit is s·m -1 ; R s is the aerodynamic damping, in s·m -1 .

[0043] In the present invention, the method for obtaining the aerodynamic damping preferably comprises the following steps: measuring the reference height of the HONO flux, and obtaining the aerodynamic damping according to equation 10 based on the reference height of the HONO flux and the surface roughness height, the Karman constant and the friction wind speed. R a ; Formula 10; In formula 10, R a is the aerodynamic damping, in s·m -1 ; Aerodynamic damping preferably under neutral conditions; z 0 is the surface roughness height, in meters, calculated using the CNMM-DNDC model; z ref is the reference height, in m; u is the friction wind speed, in m·s -1 ; K is the Karman constant, and its value is preferably 0.4.

[0044] In the present invention, the method for obtaining the quasi-laminar layer damping preferably comprises the following steps: obtaining the quasi-laminar layer damping according to Formula 11 from the Schmidt number, Prandtl number, Karman constant and friction wind speed; Formula 11; In formula 11, R b is the quasi-laminar layer damping, unit is s·m -1 ; S c is the Schmidt number, and its value is preferably 1.07; P r is the Prandtl number, and its value is preferably 0.72; K is the Karman constant, and its value is preferably 0.4; u is the friction wind speed, in m·s -1 .

[0045] In the present invention, the method for obtaining the surface damping comprises the following steps: obtaining the surface damping according to equation 12 from the surface soil moisture; Formula 12; In formula 12, R s is the surface damping, in s·m -1 ; M s(1) is the surface soil moisture, which is v / v. In the present invention, the surface soil moisture preferably adopts the dynamic simulation value of each simulation step of CNMM-DNDC. R sThe value is preferably 0.1~1000 ms -1 .

[0046] z 0 is affected by the degree of surface coverage and the height of coverage, so it varies with the growth period of vegetation. JLMonteith et al. pointed out that the roughness of a fully covered uniform vegetation surface is 0.13 times the average height of the rough unit (such as the average height of vegetation); for surfaces with incomplete vegetation coverage or vegetation with non-homogeneous species composition and irregular structure, such as plain shrubland, this relationship does not apply. However, for CNMM-DNDC model simulation, it is assumed that the vegetation of each input grid is homogeneous. In the present invention, the method for obtaining the surface roughness height preferably includes the following steps: obtaining the surface roughness height from the average vegetation height according to formula 14: Formula 14; In formula 14, H p is the average height of vegetation, in m. In the present invention, the average height of vegetation is preferably calculated using the plant growth module of CNMM-DNDC.

[0047] In the present invention, the method for obtaining the friction wind speed comprises the following steps: testing the wind speed at the reference height and the wind speed at the surface roughness height of the HONO flux test area, and obtaining the friction wind speed according to Formula 13 based on the wind speed at the reference height and the wind speed at the surface roughness height: Formula 13; In formula 13, u ref is the wind speed at the reference height, in m·s -1 ; u 0 is the wind speed at the surface roughness height, in m·s -1 ; z 0 is the surface roughness height, in m; z ref is the reference height, in m; K is the Karman constant, whose value is 0.4. In the present invention, under neutral conditions, u The wind speed at the reference height of the HONO flux test area is calculated as ( u ref , unit: m·s -1 ) and the wind speed at the surface roughness height ( u 0, unit m·s -1 ) approximate calculation, on land, due to the presence of vegetation, u 0 is usually 0.

[0048] In the present invention, the method for obtaining the wind speed at the reference height preferably comprises the following steps: testing the 3-hour average wind speed value, and obtaining the wind speed at the reference height according to Formula 21 based on the 3-hour average wind speed value and the 2-meter height as a model input variable: Formula 21.

[0049] In formula 21, u ref is the wind speed at the reference height, in m·s -1 ; u 2m is the wind speed at the surface roughness height, in m·s -1 .

[0050] Figure 1 The present invention adds a new soil HONO generation and elimination mechanism and emission and absorption process diagram based on the current version of CNMM-DNDC. The present invention seamlessly couples the physical and chemical mechanism of HNO2 in the soil and the soil-air interface into the nitrogen cycle module of the current version of the CNMM-DNDC model. [HONO] g It is the key variable controlling the exchange of HONO between soil and air. g Higher than the HONO concentration in the free atmosphere [HONO] a When HONO is released from the surface soil liquid phase, HONO will be deposited to the soil surface. g The size of the soil solution acidity [H + ] and nitrite concentration [NO2 - ], using the dynamic simulation value of each simulation step of CNMM-DNDC. In CNMM-DNDC, [H + ]Affected by the addition of exogenous organic materials, urea hydrolysis, nitrification, ammonia volatilization, organic acid dissociation, plant root secretion, Al 3+ Hydrolysis and regulation of material and water migration. Directly involved in soil solution NO2 - The scientific process of the generation and consumption of NO2 in the current version of the CNMM-DNDC model mainly includes organic matter mineralization, nitrification and denitrification based on microbial growth and death, and NO2 - With the lateral and vertical migration of moisture.

[0051] The following is an explanation of the process of constructing the plant absorption HONO based on plant leaf surface damping and atmospheric concentration.

[0052] Testing the concentration of HONO in the atmosphere, and obtaining the absorption flux of HONO by plants per unit surface area according to Formula II based on the concentration of HONO in the atmosphere; Formula II; In Formula II, U p is the HONO absorption flux of plants per unit surface area, in kg·N·ha -1 ·h -1 , f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO; f m is the effect function of surface soil moisture on plant leaf absorption of HONO; K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; LAI is the plant leaf area index, using the dynamic simulation value of each simulation step of CNMM-DNDC; P 0 is 1013hPa; P Atmospheric pressure (low and medium altitude areas P ≈ P 0), unit: hPa.

[0053] After HONO is released from the soil-atmosphere interface covered by vegetation, it must pass through the vegetation canopy and be absorbed by plant leaves before reaching the free atmosphere above the canopy. In the process of passing through the vegetation canopy, HONO may be absorbed by plant leaves, and plant leaves that deposit or adsorb NO2 will also produce HONO.

[0054] The plant's absorption of gas is directly related to the degree of stomatal opening, and the ambient temperature directly affects the degree of stomatal opening. Studies have shown that under 70% field capacity, the absorption of HONO by corn plants increases linearly with ambient temperature. The ambient temperature is tested, and the rate constant of HONO absorption per unit plant leaf area is obtained according to formula 15: Formula 15; In formula 15, K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; T a It is the ambient temperature at a height of 2m from the ground, in K.

[0055] However, the plant uptake rate constant for HONO given by Eq. 15 is K p With ambient temperatureT a The relationship is only the result of laboratory measurements of maize plants under specific soil conditions (70% of the soil's field capacity) and at a specific plant growth state (when the sixth pinnate leaf appears). K p It may also be affected by the growth state of the plant (the number of green leaves) and the soil moisture content (water stress on the plant will affect the degree of stomatal opening). Therefore, the present invention also introduces the influence function of plant leaf area index on plant leaf absorption of HONO ( f LAI ) and the influence function of surface soil moisture on plant leaf absorption of HONO ( f m ). f LAI and f m They are the dynamic simulation values ​​of plant leaf area index (LAI, dimensionless) and surface soil moisture at each simulation step of CNMM-DNDC. M s(1) function.

[0056] In the present invention, the method for obtaining the influence function of the plant leaf area index on the plant leaf absorption of HONO preferably comprises the following steps: The leaf area index is obtained from the calculation result of the plant growth module of CNMM-DNDC, and the influence function of the plant leaf area index on the absorption of HONO by the plant leaves is obtained according to Formula 16 from the model default value of the maximum leaf area index, the leaf area index and the maximum leaf area index; ...Formula 16; In formula 16, f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO, LAI is plant leaf area index, LAI max is the maximum leaf area index.

[0057] In the present invention, the method for obtaining the influence function of surface soil moisture on plant leaf absorption of HONO preferably comprises the following steps: The surface soil moisture is obtained from the calculation results of the soil environment module of CNMM-DNDC, and the model input parameters of the surface soil porosity are used. The influence function of the surface soil moisture on the absorption of HONO by plant leaves is obtained according to Formula 17 based on the surface soil moisture and the surface soil porosity; ...Formula 17; In formula 17, f m is the influence function of surface soil moisture on plant leaf absorption of HONO, Ms(1) is the surface soil moisture, unit v / v; PORE s(1) It is the porosity of surface soil, unit is v / v.

[0058] The chemical production process of HONO that constructs the surface of plant leaves is described below.

[0059] The present invention tests the reference flux of HONO emission per unit plant leaf area, and obtains the HONO emission flux per unit plant surface area according to Formula III based on the reference flux of HONO emission per unit plant leaf area; Formula III; In formula III, F p is the HONO emission flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface; f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; f RH is the effect function of environmental relative humidity on the HONO production rate on the plant leaf surface; F ref is the reference flux of HONO emission per unit plant leaf area, in kg·N·ha -1 LAI·h -1 ; LAI is the plant leaf area index, using the dynamic simulation value of each simulation step of CNMM-DNDC; The net exchange flux of HONO between the soil-plant system and the atmosphere is obtained according to Formula IV from the HONO emission flux from the soil to the atmosphere, the HONO absorption flux of the plants per unit surface area, and the HONO emission flux of the plants per unit surface area; Formula IV; In Formula IV, F HONO is the net exchange flux of HONO between the soil-plant system and the atmosphere, in kg·N·ha -1 ·h -1 .

[0060] The study found that NO2 can hydrolyze and generate HONO on the surface of plant leaves. Through single-factor control experiments, it was shown that the production rate of HONO on the surface of corn (plant) leaves is exponentially related to the ambient temperature, and is linearly affected by the relative humidity of the environment and the NO2 concentration in the atmosphere, while ultraviolet radiation (340~400nm) has no effect on it.

[0061] In the present invention, the influence function of the ambient temperature on the HONO production rate on the plant leaf surface is constructed according to the above theory. The method for obtaining the influence function of the ambient temperature on the HONO production rate on the plant leaf surface includes the following steps: The ambient temperature at a height of 2 m above the ground is tested, and the influence function of the ambient temperature on the HONO generation rate on the plant leaf surface is obtained according to Formula 18; Formula 18.

[0062] In formula 18, f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface, T a It is the ambient temperature at a height of 2m from the ground, in K.

[0063] In the present invention, the method for obtaining the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the surface of plant leaves comprises the following steps: Testing the NO2 concentration in the atmosphere, and obtaining the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the plant leaf surface according to Formula 19; Formula 19; In formula 19, f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; [NO2] a is the concentration of NO2 in the atmosphere, in mol·L -1 .

[0064] In the present invention, the method for obtaining the influence function of the relative humidity of the environment on the HONO production rate on the plant leaf surface comprises the following steps: The relative humidity of the testing environment is used to obtain the influence function of the relative humidity of the environment on the HONO production rate on the plant leaf surface according to Formula 20; Formula 20; In formula 20, f RH is the influence function of environmental relative humidity on the HONO production rate on the plant leaf surface, RH is the environmental relative humidity, the unit is %.

[0065] The present invention also provides a process model system for HONO flux simulation of an ecosystem obtained by the construction method described in the above technical solution.

[0066] In order to further illustrate the present invention, the process model system and construction method of the ecosystem HONO flux simulation provided by the present invention are described in detail below in combination with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0067] Example 1 The present invention adds soil HONO generation and elimination mechanism and emission and absorption process based on CNMM-DNDC, see Figure 1 .

[0068] Step 1: Construct the hydrogen ion (H + ) and nitrite nitrogen (NO2 - ) of the liquid phase chemical dynamic equilibrium function.

[0069] The dynamic simulation results of the CNMM-DNDC model are used to obtain the l H in soil solution + and NO2 - concentration; By the said l H in soil solution + and NO2 - The concentration and dissociation equilibrium constant of l The concentration of HNO2 in the soil solution of the layer; Formula 1; In formula 1, [HNO2] aq(l) For the l The concentration of HNO2 in the soil solution of the layer, in mol·L -1 ; k a(l) is the dissociation equilibrium constant of HNO2; [H + ] l For the l H in soil solution + The concentration is in mol·L -1 ; [NO2 - ] l For the l NO2 in soil solution - The concentration is in mol·L -1 .

[0070] Step 2: Establish the HONO gas-liquid equilibrium function based on Henry's law.

[0071] Henry's law can be used to calculate the equilibrium distribution of HNO2 between the liquid phase and the gas phase in the soil pores of each soil layer. According to formula 2, l The equilibrium partial pressure of HONO in the soil gas phase; Formula 2; In formula 2, For the l The equilibrium partial pressure of HONO in the soil gas phase is in Pa; H n(l) For HNO2 l Henry constant under the reaction environment conditions of the soil layer, unit is L·Pa·mol -1 ; According to Formula 1 and Formula 2, Formula 3 is obtained; Formula 3; According to the ideal gas state equation, l The equilibrium partial pressure of HONO in the soil gas phase and the l The soil temperature of the first layer is obtained according to Formula 4. l HONO concentration in the soil gas phase; Formula 4; In formula 4, [HONO] g(l) For the l HONO concentration in the soil gas phase, unit: mol·L -1 ; T s(l) For the l Layer soil temperature, in K; R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 ; According to the Arrhenius empirical equation for the relationship between the chemical reaction rate constant and temperature, H n(l) and k a(l) can be expressed as soil temperature T s(l) Specifically, the dynamic simulation value of each simulation step of CNMM-DNDC is used to obtain the first l The soil temperature of the first layer is given by l The dissociation equilibrium constant is obtained by using the soil temperature of the first layer and equation 7; l The soil temperature of the first layer is obtained according to formula 8. l Henry constant for the soil layer under the reaction environment conditions; Formula 7; Formula 8; In formula 7 and formula 8, T s(l) For the l Layer soil temperature; K a(298K) The dissociation equilibrium constant of HNO2 at room temperature is 5.1×10 -4 ; ΔH HNO2 The standard molar enthalpy of formation of HNO2 at room temperature and pressure is -118.83 kJ·mol -1 ; H n(298K) is the Henry constant for the equilibrium distribution of HNO2 between the soil water phase and the gas phase at room temperature, which is 2.08×10 -3 L.Pa.mol -1 ; Δ H HONO is the standard molar enthalpy of formation of the equilibrium partition reaction of HONO from liquid to gas at room temperature and pressure, which is 1423.5 kJ·mol -1 ·K -1 ; R is the universal gas constant, which is 8.314×10 -3 kJ mol -1 ·K -1 ; No. l The HONO concentration in the gas phase of the first layer of soil can move between the soil layers through diffusion driven by the concentration gradient, and finally be released into the atmosphere through the soil surface. l Layer and ( l The HONO concentration in the soil gas phase of the -1 layer is obtained according to Equation 5. l HONO in the soil gas phase moves to the first ( l -1) Diffusion rate of soil gas phase; Formula 5; In formula 5, dF (l) For HONO from soil l Layer to the first ( l -1) Diffusion rate of the layer; [HONO] g(l) For the l HONO concentration in the soil gas phase, in mol·L -1 ; [HONO] g(l-1) For the first ( l -1) HONO concentration in the soil gas phase, unit: mol·L -1 ; From the soil by HONO l Layer to the first ( l-1) layer diffusion rate, after at least 5 iterations, calculated layer by layer until the diffusion rate of HONO from the second soil layer to the surface layer is calculated. The current concentration of HONO in the surface soil gas phase is obtained according to Formula 6 based on the above diffusion rate of HONO from the second soil layer to the surface layer and the original HONO concentration in the surface soil gas phase; Formula 6; In formula 6, [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; [HONO] g(1) is the original concentration of HONO in the surface soil gas phase, in mol·L -1 ; dF 1 is the diffusion rate of HONO from the second soil layer to the surface layer.

[0072] Testing the concentration of HONO in the atmosphere, and obtaining the HONO emission flux from the soil to the atmosphere according to Formula I based on the concentration of HONO in the atmosphere; Formula I; In Formula I, F s is the HONO emission flux from soil to the atmosphere, in kg·N·ha -1 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; [HONO] g(1) ' is the HONO concentration in the surface soil gas phase, in mol·L -1 ; v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 .

[0073] Step 3: Construct the vertical transmission function between soil layers based on the HONO gas concentration gradient in the surface soil pores and the emission process function based on the HONO concentration gradient in the surface soil pores and the atmosphere.

[0074] The average vegetation height is obtained from the calculation results of the plant growth module of CNMM-DNDC, and the surface roughness height is obtained from the average vegetation height according to formula 14: Formula 14; In formula 14, H p is the average height of vegetation, in m; The wind speed at the reference height and the surface roughness height is tested with HONO flux. According to the wind speed at the reference height and the surface roughness height, the friction wind speed is obtained according to formula 13: Formula 13; In formula 13, u ref is the wind speed at the reference height, in m·s -1 ; u 0 is the wind speed at the surface roughness height, in m·s -1 ; z 0 is the surface roughness height, in m; z ref is the reference height, in meters; K is the Karman constant; In formula 13 u ref The 2-meter height and 3-hour average wind speed values ​​are used as model input variables ( u 2m ) calculation, the result is shown in formula 21; Formula 21; In formula 21, u ref is the wind speed at the reference height, in m·s -1 ; u 2m is the wind speed at the surface roughness height, in m·s -1 ; The aerodynamic damping is obtained according to Eq. 10 using the reference height of the HONO flux and the surface roughness height as well as the Karman constant and the friction wind speed: R a ; Formula 10; In formula 10, R a is the aerodynamic damping, in s·m -1 , is the aerodynamic damping under neutral conditions; z 0 is the surface roughness height, in meters, calculated using the CNMM-DNDC model; z ref is the reference height, in m; u is the friction wind speed, in m·s -1 ; K is the Karman constant, its value is 0.4; The quasi-laminar layer damping is obtained according to Equation 11 from the Schmidt number, Prandtl number, Karman constant and friction wind speed; Formula 11; In formula 11, R b is the quasi-laminar layer damping, unit is s·m -1 ; Sc is the Schmidt number, its value is 1.07; P r is the Prandtl number, which is 0.72; K is the Karman constant, its value is 0.4; u is the friction wind speed, in m·s -1 ; The surface soil moisture is obtained by using the dynamic simulation value of each simulation step of CNMM-DNDC, and the surface damping is obtained from the surface soil moisture according to formula 12; Formula 12; In formula 12, R s is the surface damping, in s·m -1 , the value is 0.1~1000 ms -1 ; M s(1) is the surface soil moisture, which is v / v and dimensionless. In the present invention, the surface soil moisture adopts the dynamic simulation value of each simulation step of CNMM-DNDC.

[0075] From the aerodynamic damping, quasi-laminar layer damping and surface damping, the gas transmission rate is obtained according to Formula 9: Formula 9.

[0076] The concentration of HONO in the atmosphere is tested, and the concentration of HONO in the atmosphere, the concentration of HONO in the surface soil gas phase and the gas transmission rate are determined. v According to formula I, the HONO emission flux from soil to atmosphere is obtained: F s ; Formula I; In Formula I, F s is the HONO emission flux from soil to the atmosphere, in kg·N·ha -1 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 .

[0077] Step 4: Construct the plant absorption HONO process based on leaf surface damping and atmospheric concentration.

[0078] The method for obtaining the influence function of HONO absorption per unit plant leaf area comprises the following steps: The ambient temperature at a height of 2 m above the ground was tested, and the rate constant of HONO absorption per unit plant leaf area was obtained from the ambient temperature according to Formula 15: Formula 15; In formula 15, K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; T a It is the ambient temperature at a height of 2m from the ground, in K.

[0079] The leaf area index is obtained by the calculation result of the plant growth module of CNMM-DNDC. The influence function of the plant leaf area index on the absorption of HONO by plant leaves is obtained according to the model default value of the maximum leaf area index, the leaf area index and the maximum leaf area index according to formula 16. f LAI ; The surface soil moisture is obtained by the calculation results of the soil environment module of CNMM-DNDC, and the model input parameters of the surface soil porosity are used. The influence function of plant leaf absorption of HONO is obtained according to Formula 17 based on the surface soil moisture and surface soil porosity. f m ; Formula 16; Formula 17; In formula 16, f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO, LAI is plant leaf area index, LAI max is the maximum leaf area index.

[0080] In formula 17, f m is the influence function of surface soil moisture on plant leaf absorption of HONO, M s(1) is the surface soil moisture, in v / v; PORE s(1) The porosity of the surface soil, expressed in v / v.

[0081] The concentration of HONO in the atmosphere is tested, and the rate constant of HONO absorption per unit plant leaf area is calculated from the concentration of HONO in the atmosphere. K p , Plant leaf area index influence function f LAI , soil moisture influence function fm and the plant leaf area index LAI, the absorption flux of HONO by plants per unit surface area is obtained according to formula II; Formula II; In Formula II, U p is the HONO absorption flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f LAI is the effect function of plant liquid area index on plant leaf absorption of HONO; f m is the effect function of surface soil moisture on plant leaf absorption of HONO; K p is the rate constant of HONO absorption per unit plant leaf area; LAI is the plant leaf area index, which adopts the dynamic simulation value of each simulation step of CNMM-DNDC; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; T 0 is 273.15K; P 0 is 1013hPa; P Atmospheric pressure (low and medium altitude areas P ≈ P 0).

[0082] Step 5: Establish the HONO chemical production process on the plant leaf surface.

[0083] The ambient temperature at a height of 2m from the ground T a According to formula 18, the influence function of ambient temperature on the HONO production rate on the plant leaf surface is obtained: f T ; Formula 18; In formula 18, f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface, T a It is the ambient temperature at a height of 2m from the ground, in K.

[0084] Test the NO2 concentration in the atmosphere, and obtain the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the plant leaf surface according to formula 19. f con ; Formula 19; In formula 19,f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; [NO2] a is the concentration of NO2 in the atmosphere, in mol·L -1 .

[0085] The relative humidity RH of the test environment is used to obtain the influence function of the relative humidity of the environment on the HONO generation rate on the plant leaf surface according to formula 20. f RH ; Formula 20; In formula 20, f RH is the effect function of relative humidity on the HONO production rate on the plant leaf surface, RH is the relative humidity of the environment, the unit is % Test reference flux of HONO emission per unit plant leaf area F ref and ambient relative humidity, the reference flux of HONO emitted per unit plant leaf area F ref And the influence function of the relative humidity of the environment, the plant leaf area index LAI, and the ambient temperature on the HONO production rate on the plant leaf surface f T , the effect function of atmospheric NO2 concentration on the HONO production rate on plant leaf surface f con According to formula III, the HONO emission flux of plants per unit surface area is obtained: F p ; Formula III; In formula III, F p is the HONO emission flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f T is the effect function of ambient temperature on the HONO production rate on the plant leaf surface; f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; f RH is the effect function of environmental relative humidity on the HONO production rate on the plant leaf surface; F ref is the reference flux of HONO emission per unit plant leaf area, in kg·N·ha -1 LAI·h-1 ; LAI is the leaf area index of plants, which adopts the dynamic simulation value of each simulation step of CNMM-DNDC.

[0086] HONO emission flux from the soil to the atmosphere F s , the absorption flux of HONO by plants per unit surface area U p and the HONO emission flux per unit surface area of ​​plants F p According to formula IV, the net HONO exchange flux between the soil-plant system and the atmosphere is obtained: F HONO ; Formula IV; In Formula IV, F HONO is the net exchange flux of HONO between the soil-plant system and the atmosphere, in kg·N·ha -1 ·h -1 .

[0087] Example 2 The process model system for HONO flux simulation of ecosystems constructed in Example 1 was used to simulate the emission of soil HONO from a summer corn-winter wheat rotation farmland in Haidian District, Beijing in 2001. According to the assumptions based on the survey of published literature, the concentration of HONO in the atmosphere during the day and at night [HONO] a were set to 0.1 ppbv (i.e. 0.007×10 - 6 mol·L -1 ) and 0.2 ppbv (i.e. 0.014×10 -6 mol·L -1 ), the concentration of NO2 in the atmosphere ([NO2] a ) is 40 ppbv (i.e. 2.86×10 -6 mol·L -1 ), f LAI and f m All are 0.1, the reference flux of HONO emission per unit leaf area F ref The default value is 1.5×10 -4 kg N ha -1 ·h -1 . Figure 2This is a simulation result diagram of HONO emission flux under the process model system of ecosystem HONO flux simulation constructed by the present invention, wherein negative values ​​indicate that the soil absorbs HONO in the atmosphere, and positive values ​​indicate that the soil emits HONO into the atmosphere.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for constructing a process model system for HONO flux simulation of an ecosystem, comprising the following steps: Testing the concentration of HONO in the atmosphere, and obtaining the HONO emission flux from the soil to the atmosphere according to Formula I based on the concentration of HONO in the atmosphere; Formula I; In Formula I, F s is the HONO emission flux from soil to the atmosphere, in kg·N·ha -1 ·h -1 ; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 ; Testing the concentration of HONO in the atmosphere, and obtaining the absorption flux of HONO by plants per unit surface area according to Formula II based on the concentration of HONO in the atmosphere; Formula II; In Formula II, U p is the HONO absorption flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO; f m is the effect function of surface soil moisture on plant leaf absorption of HONO; K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; LAI is the leaf area index of plants, using the dynamic simulation value of each simulation step of CNMM-DNDC; [HONO] a is the concentration of HONO in the atmosphere, in mol·L -1 ; T 0 is 273.15K; P 0 is 1013hPa; P is the atmospheric pressure, in hPa; The reference flux of HONO emitted per unit plant leaf area is tested, and the emission flux of HONO by plants per unit surface area is obtained according to Formula III based on the reference flux of HONO emitted per unit plant leaf area; Formula III; In formula III, F p is the HONO emission flux of plants per unit surface area, in kg·N·ha -1 ·h -1 ; f T is the function of the effect of ambient temperature on the HONO production rate on the plant leaf surface; f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; f RH is the effect function of environmental relative humidity on the HONO production rate on the plant leaf surface; F ref is the reference flux of HONO emission per unit plant leaf area, in kg·N·m -2 LAI·h -1 ; LAI is the plant leaf area index, using the dynamic simulation value of each simulation step of CNMM-DNDC; The net exchange flux of HONO between the soil-plant system and the atmosphere is obtained according to Formula IV from the HONO emission flux from the soil to the atmosphere, the HONO absorption flux of the plants per unit surface area, and the HONO emission flux of the plants per unit surface area; Formula IV; In Formula IV, F HONO is the net HONO exchange flux between the soil-plant system and the atmosphere, in kg·N·ha -1 ·h -1 .

2. The construction method according to claim 1, characterized in that: The method for obtaining the HONO concentration in the surface soil gas phase comprises the following steps: The dynamic simulation results of the CNMM-DNDC model are used to obtain the l H in soil solution + and NO2 - concentration; By the said l H in soil solution + and NO2 - The concentration of l The concentration of HNO2 in the soil solution of the layer; Formula 1; In formula 1, [HNO2] aq(l) For the l The concentration of HNO2 in the soil solution of the layer, in mol·L -1 ; k a(l) is the dissociation equilibrium constant of HNO2; [H + ] l For the l H in soil solution + The concentration is in mol·L -1 ; [NO2 - ] l For the l NO2 in soil solution - The concentration is in mol·L -1 ; From formula 2, we can get l The equilibrium partial pressure of HONO in the soil gas phase; Formula 2; In formula 2, For the l The equilibrium partial pressure of HONO in the soil gas phase is in Pa; H n(l) For HNO2 l Henry constant under the reaction environment conditions of the soil layer, unit is L·Pa·mol -1 ; According to Formula 1 and Formula 2, Formula 3 is obtained; Formula 3; By the said l The equilibrium partial pressure of HONO in the soil gas phase is obtained according to Eq. l HONO concentration in the soil gas phase of the layer; Formula 4; In formula 4, [HONO] g(l) For the l HONO concentration in the soil gas phase, unit: mol·L -1 ; T s(l) For the l Layer soil temperature, in K; R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 ; By the said l Layer and ( l The HONO concentration in the soil gas phase of the -1 layer is obtained according to Equation 5. l HONO in the soil gas phase moves to the first ( l -1) Diffusion rate of soil layer; Formula 5; In formula 5, dF (l) For HONO from soil l Layer to the first ( l -1) Diffusion rate of the layer; [HONO] g(l) For the l HONO concentration in the soil gas phase, unit: mol·L -1 ; [HONO] g(l-1) For the first ( l -1) HONO concentration in the soil gas phase, unit: mol·L -1 ; From the soil by HONO l Layer to the first ( l -1) layer diffusion rate, after at least 5 iterations, calculated layer by layer until the diffusion rate of HONO from the second soil layer to the surface layer is calculated. The current concentration of HONO in the surface soil gas phase is obtained according to Formula 6 based on the above diffusion rate of HONO from the second soil layer to the surface layer and the original HONO concentration in the surface soil gas phase; Formula 6; In formula 6, [HONO] g(1) ' is the current concentration of HONO in the surface soil gas phase, in mol·L -1 ; [HONO] g(1) is the original concentration of HONO in the surface soil gas phase, in mol·L -1 ; dF 1 is the diffusion rate of HONO from the second soil layer to the surface layer.

3. The construction method according to claim 2, characterized in that: The method for obtaining the dissociation equilibrium constant of HNO2 comprises the following steps: l The dissociation equilibrium constant is obtained according to Formula 7; Formula 7; In formula 7, k a(l) is the dissociation equilibrium constant of HNO2; T s(l) For the l Layer soil temperature, in K; K a(298K) is the dissociation equilibrium constant of HNO2 at room temperature; Δ H HNO2 is the standard molar enthalpy of formation of HNO2 at room temperature and pressure, in kJ·mol -1 ; R is the universal gas constant, which is 8.314×10 -3 kJ·mol -1 ·K -1 ; The HNO2 in soil l The method for obtaining the Henry constant under the layer reaction environment conditions comprises the following steps: l The soil temperature of the first layer is obtained according to formula 8. l Henry constant for the soil layer under the reaction environment conditions; Formula 8; In formula 8, H n(l) HNO2 in soil l Henry constant under the environmental conditions of the layer reaction, unit is L·Pa·mol -1 ; T s(l) For the l Layer soil temperature, in K; H n(298K) is the Henry constant for the equilibrium distribution of HNO2 between the soil water phase and the gas phase at room temperature, in L·Pa·mol -1 ; Δ H HONO is the standard molar formation enthalpy of HONO from the soil liquid phase to the gas phase at room temperature and pressure, in kJ·mol -1 ; R is the universal gas constant.

4. The construction method according to claim 1, characterized in that: The method for obtaining the gas transmission rate of HONO from soil to atmosphere comprises the following steps: From the aerodynamic damping, quasi-laminar layer damping and surface damping, the gas transmission rate of HONO from soil to atmosphere is obtained according to Equation 9; Formula 9; In formula 9, v is the gas transmission rate of HONO from soil to atmosphere, in m·s -1 ; R a is the aerodynamic damping, in s·m -1 ; R b is the quasi-laminar layer damping, unit is s·m -1 ; R s is the aerodynamic damping, in s·m -1 ; The method for obtaining the aerodynamic damping comprises the following steps: measuring a reference height of the HONO flux, and obtaining the aerodynamic damping according to equation 10 based on the reference height of the HONO flux and the surface roughness height; Formula 10; In formula 10, R a is the aerodynamic damping, in s·m -1 ; z 0 is the surface roughness height, in m; z ref is the reference height for measuring HONO flux, in meters; u is the friction wind speed, in m·s -1 ; K is the Karman constant, its value is 0.4; The method for obtaining the quasi-laminar layer damping comprises the following steps: obtaining the quasi-laminar layer damping according to Formula 11 from the Schmidt number, the Prandtl number, the Karman constant and the friction wind speed; Formula 11; In formula 11, R b is the quasi-laminar layer damping, unit is s·m -1 ; S c is the Schmidt number, its value is 1.07; P r is the Prandtl number, which is 0.72; K is the Karman constant, its value is 0.4; u is the friction wind speed, in m·s -1 ; The method for obtaining the surface damping comprises the following steps: obtaining the surface damping from the surface soil moisture according to equation 12; Formula 12; In formula 12, R s is the surface damping, in s·m -1 ; M s(1) is the surface soil moisture, in v / v.

5. The construction method according to claim 4, characterized in that: The method for obtaining the friction wind speed comprises the following steps: The wind speed at the reference height of the HONO flux test is measured, and the friction wind speed is obtained from the wind speed at the reference height and the wind speed at the surface roughness height according to Formula 13: Formula 13; In formula 13, u is the friction wind speed, in m·s -1 ; u ref is the wind speed at the reference height, in m·s -1 ; u 0 is the wind speed at the surface roughness height, in m·s -1 ; z 0 is the surface roughness height, in m; z ref is the reference height, in m; K is the Karman constant, its value is 0.4; The method for obtaining the surface roughness height comprises the following steps: The average vegetation height is obtained from the calculation results of the plant growth module of CNMM-DNDC, and the surface roughness height is obtained from the average vegetation height according to formula 14: Formula 14; In formula 14, z 0 is the surface roughness height, in m; H p is the average height of vegetation, in meters.

6. The construction method according to claim 1, characterized in that: The method for obtaining the influence function of HONO absorption per unit plant leaf area comprises the following steps: The ambient temperature at a height of 2 m above the ground was tested, and the rate constant of HONO absorption per unit plant leaf area was obtained from the ambient temperature according to Formula 15: Formula 15; In formula 15, K p is the rate constant of HONO absorption per unit plant leaf area, in m -2 ·h -1 ; T a It is the ambient temperature at a height of 2m from the ground, in K.

7. The construction method according to claim 1, characterized in that: The method for obtaining the influence function of plant leaf area index on plant leaf absorption of HONO comprises the following steps: The leaf area index is obtained from the calculation result of the plant growth module of CNMM-DNDC, and the influence function of the plant leaf area index on the absorption of HONO by the plant leaves is obtained according to Formula 16 from the model default value of the maximum leaf area index, the leaf area index and the maximum leaf area index; Formula 16; In formula 16, f LAI is the influence function of plant leaf area index on plant leaf absorption of HONO, LAI is plant leaf area index, LAI max is the maximum leaf area index.

8. The construction method according to claim 1, characterized in that: The method for obtaining the influence function of surface soil moisture on plant leaf absorption of HONO comprises the following steps: The surface soil moisture is obtained from the calculation results of the soil environment module of CNMM-DNDC, and the model input parameters of the surface soil porosity are used. The influence function of the surface soil moisture on the absorption of HONO by plant leaves is obtained according to Formula 17 based on the surface soil moisture and the surface soil porosity; Formula 17; In formula 17, f m is the effect function of surface soil moisture on plant leaf absorption of HONO; M s(1) is the surface soil moisture, unit v / v; PORE s(1) It is the porosity of surface soil, unit is v / v.

9. The construction method according to claim 1, characterized in that: The method for obtaining the influence function of the ambient temperature on the HONO production rate on the plant leaf surface comprises the following steps: The ambient temperature at a height of 2 m above the ground is tested, and the influence function of the ambient temperature on the HONO generation rate on the plant leaf surface is obtained according to Formula 18. Formula 18; In formula 18, f T is the function of the effect of ambient temperature on the HONO production rate on the plant leaf surface; T a is the ambient temperature at a height of 2m from the ground, in K; The method for obtaining the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the surface of plant leaves comprises the following steps: Testing the NO2 concentration in the atmosphere, and obtaining the influence function of the NO2 concentration in the atmosphere on the HONO production rate on the plant leaf surface according to Formula 19; Formula 19; In formula 19, f con is the function of the effect of atmospheric NO2 concentration on the HONO production rate on the plant leaf surface; [NO2] a is the concentration of NO2 in the atmosphere, in mol·L -1 ; The method for obtaining the influence function of the relative humidity of the environment on the HONO production rate on the plant leaf surface comprises the following steps: The relative humidity of the testing environment is used to obtain the influence function of the relative humidity of the environment on the HONO production rate on the plant leaf surface according to Formula 20; Formula 20; In formula 20, f RH is the influence function of environmental relative humidity on the HONO production rate on the plant leaf surface; RH is the environmental relative humidity, the unit is %.

10. A process model system for ecosystem HONO flux simulation obtained by the construction method according to any one of claims 1 to 9.

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