Simulation method for atmospheric energy exchange of flooding wetland based on dynamic interface conversion

Abstract

The application discloses a flooding wetland atmospheric energy exchange simulation method based on dynamic interface conversion and relates to the technical field of ecological environment simulation. The method comprises the following steps: collecting meteorological driving data, hydrological driving data and underlying surface physical parameters; determining the state of the flooding wetland interface according to real-time monitoring or simulation of the submerged water depth data; calling the corresponding energy transmission model to simulate the dynamic conversion process of the energy transmission mechanism based on the determination result of the interface state; introducing the turbulent diffusion effect and the convection mixing effect of the water body when simulating the water-air and water-soil composite mode; introducing the turbulent exchange effect of the soil-atmosphere interface when simulating the soil-air dominant mode, and coupling the dynamic influence of soil humidity on the soil thermal conductivity coefficient. The application realizes the seamless dynamic conversion of the water-air and soil-air interface mode in the flood period by introducing the dry-wet dynamic boundary processing technology.

Description

Technical Field

[0001] This invention relates to the field of ecological environment simulation technology, specifically a method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation. Background Technology

[0002] As a typical type of wetland affected by the periodic inundation of river and lake water levels, floodplain wetlands exhibit a unique "dynamic interface" where the underlying surface properties dynamically shift between "water body" and "exposed soil" during the flood cycle. The physical properties of this interface (such as albedo, heat capacity, and thermal conductivity) undergo drastic changes, leading to drastically different energy transfer mechanisms.

[0003] Currently, energy exchange simulations primarily rely on land surface process models or one-dimensional vertical models. However, the parameterization schemes for the underlying surface in these traditional models are mostly designed for static interfaces, failing to effectively characterize the dynamic transition processes between the "water-air" and "soil-air" interface modes in floodplains. Specifically, existing models have fixed boundaries and fail to couple the nonlinear perturbations of energy processes caused by floodplain hydrological processes (such as inundation duration and water depth changes); they also lack detailed descriptions of key physical mechanisms of interface transitions (such as abrupt changes in albedo, abrupt changes in medium thermal conductivity, and the coupling of soil moisture and thermal properties). This limits the accuracy of traditional models in simulating energy exchange in floodplains, making it difficult to deeply reveal the impact mechanisms of dynamic interfaces on energy balance. Summary of the Invention

[0004] The purpose of this invention is to provide a simulation method for atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for simulating atmospheric energy exchange in floodplains based on dynamic interface transformation, the method comprising:

[0006] Collect meteorological driving data, hydrological driving data, and underlying surface physical parameters;

[0007] The state of the floodplain wetland interface is determined based on real-time monitoring or simulated inundation depth data; the state includes the inundation period and the exposure period.

[0008] Based on the determination of the interface state, the corresponding energy transfer model is called to simulate the dynamic conversion process of the energy transfer mechanism. Specifically, when the interface changes from the exposure period to the submerged period, the energy transfer is simulated to change from the soil-air dominant mode to the water-air and water-soil composite mode. When the interface changes from the submerged period to the exposure period, the energy transfer is simulated to change from the water-air and water-soil composite mode to the soil-air dominant mode.

[0009] The dynamic conversion process includes dynamically adjusting the albedo based on the interface state conversion to simulate the abrupt change in reflected radiation, and simulating the continuous heat flux transfer process based on the abrupt change in thermal conductivity at the medium interface. When simulating water-air and water-soil composite models, the turbulent diffusion effect and convection mixing effect of water are introduced. When simulating the soil-air dominant model, the turbulent exchange effect of the soil-atmosphere interface is introduced, and the dynamic influence of soil moisture on soil thermal conductivity is coupled.

[0010] The constructed energy balance equations were numerically solved, and the simulation results were verified using observational data.

[0011] According to the above scheme, meteorological driving data include air temperature, humidity, wind speed, downward shortwave radiation, downward longwave radiation, precipitation, and air pressure; hydrological driving data include water depth and soil moisture; and underlying surface physical parameters include albedo, thermal conductivity, extinction coefficient, water surface emissivity, momentum roughness, sensible thermal roughness, and latent thermal roughness during the flooding and exposure periods.

[0012] According to the above scheme, the determination of the state of the floodplain wetland interface includes judging the inundation water depth data of the current calculation period based on a preset critical water depth value; if the inundation water depth data is greater than zero, the current interface state is determined to be inundation period; if the inundation water depth data is equal to zero, the current interface state is determined to be exposure period.

[0013] According to the above scheme, when the interface transitions from the exposure period to the submersion period, the simulated energy transfer shifts from a soil-air dominant mode to a water-air and water-soil composite mode, including:

[0014] The soil-atmosphere dominant model corresponds to the exposure period. When floodplains are in the exposure period, that is, when the water depth is zero, the underlying surface is bare soil or moist mudflats. During this period, energy exchange occurs directly between the soil surface and the atmosphere. Therefore, the dominant mechanism of energy transfer is the thermal conduction of the soil itself and the turbulent exchange between the soil and the near-surface atmosphere. Energy is mainly conducted vertically through the soil solid medium and exchanged with the atmosphere at the soil-atmosphere interface in the form of sensible heat and latent heat.

[0015] The water-air and water-soil composite models correspond to the inundation period. When the floodplain is in the inundation period, that is, when the water depth is greater than zero, the underlying surface is covered by water. During this period, energy first enters the overlying water body, then is redistributed in the water body, and finally is transferred to the underlying soil, which includes two series of interfacial processes: the water-air interface, where energy is absorbed by the water surface and exchanges sensible heat, latent heat and radiation with the atmosphere; and the water-soil interface, where after the water body absorbs energy, its interior transfers and redistributes energy in the vertical direction through the turbulent diffusion effect and convection mixing effect of the water body, and exchanges heat with the saturated soil at the bottom.

[0016] When the interface changes from the exposure period to the submerged period, the soil heat conduction flux of the soil-atmosphere interface under the soil-atmosphere dominant mode during the exposure period is used as the lower boundary initial condition of the water-atmosphere interface energy balance equation in the water-atmosphere and water-soil composite modes during the submerged period.

[0017] An energy balance equation for the interface between the overlying water body and the atmosphere is constructed to simulate the energy transfer process at the water-air interface. The energy balance equation for the interface between the overlying water body and the atmosphere is as follows:

[0018] ;

[0019] Among them, T w The water temperature is represented by t; time is represented by z; water depth is represented by A(z); and the lake area at depth z is represented by d. w The diffusion coefficient of water molecules is represented by D(z,t); the turbulent diffusion coefficient of water is represented by c. w The term represents the volumetric heat capacity of the water body; φ represents the heat source term; and Conv represents the convective mixing process term caused by the instability of the density layer structure. The Conv term calculates the corresponding water density based on the temperature of each water layer, judges the stability of the water density layer structure based on the water density, and characterizes the convective mixing process caused by the instability of the density layer structure.

[0020] An energy balance equation for the subsaturated soil was constructed to simulate the heat exchange process at the water-soil interface. The energy balance equation for the subsaturated soil is as follows:

[0021] ;

[0022] Among them, T s This is expressed as the bottom soil temperature; d s c represents the molecular diffusion coefficient of the bottom soil layer. s This is expressed as the volumetric heat capacity of the bottom soil layer;

[0023] The turbulent diffusion coefficient is given by the following formula:

[0024] ;

[0025] Where, k v Represented as the von Kármán constant; w * It is expressed as the surface friction velocity; P0 represents Prandtl's constant; k * It is expressed as a function of longitude and wind speed; 37 is an empirical coefficient characterizing the effect of fluid stability on turbulence suppression; Ri represents the gradient Richardson number;

[0026] The Richardson number for the gradient is given by the following formula:

[0027] ;

[0028] Where N represents the Brunt-Vaisala frequency; k represents the von Kármán constant;

[0029] Brunt-Vaisala frequency, formula as follows:

[0030] ;

[0031] Where g is the acceleration due to gravity; ρ is the density of water; and z is the water depth.

[0032] According to the above scheme, when the interface transitions from the submerged period to the exposed period, the simulated energy transfer shifts from a water-air and water-soil composite model to a soil-air dominant model, including:

[0033] When the interface changes from the flooding period to the exposure period, the soil heat flux of the water-soil interface under the water-air and water-soil composite modes during the flooding period is used as the upper boundary initial condition of the soil-atmosphere interface energy balance equation under the soil-air dominant mode during the exposure period, and the turbulent diffusion effect term and the convection mixing effect term contained in the energy balance equation of the overlying water body during the flooding period are removed.

[0034] An energy balance equation for the soil-atmosphere interface, primarily based on soil heat conduction, is constructed to simulate the energy transfer process at the soil-atmosphere interface. The soil-atmosphere interface energy balance equation is as follows:

[0035] ;

[0036] Among them, T s This is expressed as the bottom soil temperature; d s c represents the molecular diffusion coefficient of the bottom soil layer. s The volumetric heat capacity of the bottom soil layer is represented by t; time is represented by z; water depth is represented by φ; and the heat source term is represented by Q. s-a It is expressed as the turbulent exchange flux at the soil-atmosphere interface.

[0037] According to the above scheme, the albedo is dynamically adjusted based on the interface state transition to simulate the abrupt change in reflected radiation, including:

[0038] The albedo under the current interface state is obtained by taking the water albedo when the interface state is in the submerged period and the soil albedo when the interface state is in the exposed period, so as to realize the dynamic switching of albedo with the interface state.

[0039] The net longwave radiation flux entering the interface is corrected by the change in the dynamic interface albedo; the net longwave radiation flux is the difference between the net surface radiation and the downward shortwave radiation reflected by the interface, as shown in the following formula:

[0040] ;

[0041] Among them, Ln Represented as the net longwave radiation flux entering the interface; R n This is expressed as net surface radiation. It is represented as downward shortwave radiation; α is the albedo under the current interface state.

[0042] According to the above scheme, the continuous heat flux transport process is simulated based on the abrupt change in thermal conductivity at the medium interface, including:

[0043] At the water-air interface, the heat flux continuity condition is applied, meaning that although the thermal conductivity coefficients of the atmosphere and the water medium differ significantly, the heat flux perpendicular to the interface remains continuous; the formula is as follows:

[0044] ;

[0045] Among them, K a Expressed as atmospheric thermal conductivity, K w Expressed as the thermal conductivity coefficient of water, It is represented as a vertical temperature gradient; the same heat flux continuity condition is applied at the water-soil interface.

[0046] According to the above scheme, the dynamic effects of coupled soil moisture on soil thermal conductivity include:

[0047] The soil thermal conductivity coefficient is calculated dynamically based on soil volumetric moisture content. The formula for the soil thermal conductivity coefficient is as follows:

[0048] ;

[0049] Among them, K s K represents the calculated soil thermal conductivity coefficient. d θ represents the thermal conductivity coefficient of dry soil; θ represents the soil volumetric moisture content; and b represents a constant characterizing the influence of soil moisture on the thermal conductivity coefficient.

[0050] Based on the above scheme, the constructed energy balance equation is numerically solved, and the simulation results are verified using observational data, including:

[0051] The water and soil media were vertically stratified and discretized; a fine stratification scheme was used for the water layer and the shallow soil with active heat exchange, while a coarse stratification scheme was used for the deep soil with slow heat exchange; the energy balance control equation was discretized using the implicit difference method, and the discretized numerical model was solved by the iterative method.

[0052] The upper boundary conditions of the energy balance governing equations are jointly determined by the radiation flux absorbed by the surface of the floodplain, the flux exchange between the land surface and the atmosphere, and the energy brought by atmospheric precipitation. According to Fourier's law of heat conduction, the formula for the upper boundary conditions is as follows:

[0053] ;

[0054] ;

[0055] Where Q represents the heat flux entering the interface; d w The diffusion coefficient of water molecules is represented by D(z,t); the turbulent diffusion coefficient of water is represented by T. w The water temperature is represented by z; the water depth is represented by S. n Represented as the net shortwave radiation flux entering the interface; L n L represents the net longwave radiation flux entering the interface. u H is expressed as the long-wavelength radiation flux emitted from the interface. s Expressed as sensible heat flux; L lv E represents the latent heat of vaporization; E represents the evaporation flux.

[0056] The vertical profiles of water temperature, soil temperature, sensible heat flux and latent heat flux measured by wetland observation stations were compared and verified with the corresponding output results of the model; and the Nash efficiency coefficient, coefficient of determination and root mean square error (RMSE) were used as accuracy evaluation indicators.

[0057] Compared with the prior art, the beneficial effects of the present invention are:

[0058] 1. This invention introduces dry-wet dynamic boundary processing technology to achieve a clear and seamless dynamic transformation of the physical mechanism of the water-air and soil-air interface modes during the flood cycle, solves the inherent bias of traditional static interface models, and improves the simulation accuracy of complex energy exchange processes in floodplains.

[0059] 2. This invention can precisely couple flooding hydrological processes with energy exchange processes, simulate the nonlinear effects of key hydrological factors such as inundation duration and water depth on wetland energy balance, and more accurately demonstrate the energy exchange driving mechanism of dynamic interfaces. Attached Figure Description

[0060] Figure 1 This is a flowchart illustrating the steps of the present invention's method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] Example: Figure 1 As shown, this invention provides a technical solution: a method for simulating atmospheric energy exchange in floodplains based on dynamic interface transformation. The method includes:

[0063] Collect meteorological driving data, hydrological driving data, and underlying surface physical parameters;

[0064] Specifically, meteorological driving data include air temperature, humidity, wind speed, downward shortwave radiation, downward longwave radiation, precipitation, and air pressure; hydrological driving data include water depth and soil moisture; and underlying surface physical parameters include albedo, thermal conductivity, extinction coefficient, water surface emissivity, momentum roughness, sensible thermal roughness, and latent thermal roughness during the flooding and exposure periods.

[0065] Thermal conductivity, extinction coefficient, water surface emissivity, momentum roughness, sensible thermal roughness, and latent thermal roughness are all key parameters characterizing the physical properties of the underlying surface, used to accurately describe the energy transfer and distribution process at the interface.

[0066] The state of the floodplain wetland interface is determined based on real-time monitoring or simulated inundation depth data; the state includes the inundation period and the exposure period.

[0067] Specifically, determining the state of the floodplain wetland interface involves using a preset critical water depth value as a criterion to assess the inundation water depth data for the current calculation period. If the inundation water depth data is greater than zero, the current interface state is determined to be in the inundation period; if the inundation water depth data is equal to zero, the current interface state is determined to be the exposure period. The determination is based on real-time monitoring or simulated inundation water depth data to determine the state of the floodplain wetland interface for the current calculation period.

[0068] Based on the determination of the interface state, the corresponding energy transfer model is called to simulate the dynamic conversion process of the energy transfer mechanism. Specifically, when the interface changes from the exposure period to the submerged period, the energy transfer is simulated to change from the soil-air dominant mode to the water-air and water-soil composite mode. When the interface changes from the submerged period to the exposure period, the energy transfer is simulated to change from the water-air and water-soil composite mode to the soil-air dominant mode.

[0069] Specifically, when the interface changes from the exposure period to the submerged period, the soil heat conduction flux of the soil-atmosphere interface under the soil-atmosphere dominant mode during the exposure period is used as the lower boundary initial condition of the water-atmosphere interface energy balance equation in the water-atmosphere and water-soil composite modes during the submerged period.

[0070] An energy balance equation for the interface between the overlying water body and the atmosphere is constructed to simulate the energy transfer process at the water-air interface. The energy balance equation for the interface between the overlying water body and the atmosphere is as follows:

[0071] ;

[0072] Among them, T wThe water temperature is represented by t; time is represented by z; water depth is represented by A(z); and the lake area at depth z is represented by d. w The diffusion coefficient of water molecules is represented by D(z,t); the turbulent diffusion coefficient of water is represented by c. w The term represents the volumetric heat capacity of the water body; φ represents the heat source term; and Conv represents the convective mixing process term caused by the instability of the density layer structure. The Conv term calculates the corresponding water density based on the temperature of each water layer, and judges the stability of the water density layer structure based on the water density, thus characterizing the convective mixing process caused by the instability of the density layer structure. The convective mixing process uses a convective mixing mechanism with density as the judgment standard to ensure that each layer of the water body is in a stable state.

[0073] An energy balance equation for the subsaturated soil was constructed to simulate the heat exchange process at the water-soil interface. The energy balance equation for the subsaturated soil is as follows:

[0074] ;

[0075] Among them, T s This is expressed as the bottom soil temperature; d s c represents the molecular diffusion coefficient of the bottom soil layer. s This represents the volumetric heat capacity of the bottom soil layer; the values ​​for the soil molecular diffusion coefficient and volumetric heat capacity are 1.157 × 10⁻⁶. -7 ~1.127×10 -6 m 2 / s and 1.4×10 6 ~3.8×10 6 Jm -3 K -1 .

[0076] The turbulent diffusion coefficient is given by the following formula:

[0077] ;

[0078] Where, k v Represented as the von Kármán constant; w * It is expressed as the surface friction velocity; P0 represents Prandtl's constant; k * It is expressed as a function of longitude and wind speed; 37 is an empirical coefficient characterizing the effect of fluid stability on turbulence suppression; Ri represents the gradient Richardson number;

[0079] Surface friction speed w * Defined as ;k * The parameter is defined as follows ;u a The wind speed is represented by φ at the reference altitude; φ represents the longitude of the object under study; N is the Brunt-Vaisala frequency.

[0080] The Richardson number for the gradient is given by the following formula:

[0081] ;

[0082] Where N represents the Brunt-Vaisala frequency; k represents the von Kármán constant;

[0083] Brunt-Vaisala frequency, formula as follows:

[0084] ;

[0085] Where g is the acceleration due to gravity; ρ is the density of water; z is the water depth; and the water density ρ is the water temperature T. w The function is ;

[0086] Specifically, when the interface changes from the flooding period to the exposure period, the soil heat flux of the water-soil interface under the water-air and water-soil composite modes during the flooding period is used as the upper boundary initial condition of the soil-atmosphere interface energy balance equation under the soil-air dominant mode during the exposure period, and the turbulent diffusion effect term and the convection mixing effect term contained in the energy balance equation of the overlying water body during the flooding period are removed.

[0087] An energy balance equation for the soil-atmosphere interface, primarily based on soil heat conduction, is constructed to simulate the energy transfer process at the soil-atmosphere interface. The soil-atmosphere interface energy balance equation is as follows:

[0088] ;

[0089] Among them, T s This is expressed as the bottom soil temperature; d s c represents the molecular diffusion coefficient of the bottom soil layer. s The volumetric heat capacity of the bottom soil layer is represented by t; time is represented by z; water depth is represented by φ; and the heat source term is represented by Q. s-a This is expressed as the turbulent exchange flux at the soil-atmosphere interface. For floodplain wetland interfaces during the exposure period, the water-air heat exchange process transforms into a soil-air heat exchange process.

[0090] The dynamic conversion process includes dynamically adjusting the albedo based on the interface state conversion to simulate the abrupt change in reflected radiation, and simulating the continuous heat flux transfer process based on the abrupt change in thermal conductivity at the medium interface. When simulating water-air and water-soil composite models, the turbulent diffusion effect and convection mixing effect of water are introduced. When simulating the soil-air dominant model, the turbulent exchange effect of the soil-atmosphere interface is introduced, and the dynamic influence of soil moisture on soil thermal conductivity is coupled.

[0091] Specifically, the albedo under the current interface state is obtained by taking the water albedo when the interface state is in the submerged period and the soil albedo when the interface state is in the exposed period, so as to realize the dynamic switching of albedo with the interface state.

[0092] The net longwave radiation flux entering the interface is corrected by the change in the dynamic interface albedo; the net longwave radiation flux is the difference between the net surface radiation and the downward shortwave radiation reflected by the interface, as shown in the following formula:

[0093] ;

[0094] Among them, L n Represented as the net longwave radiation flux entering the interface; R n This is expressed as net surface radiation. It represents downward shortwave radiation; α represents the albedo under the current interface conditions. The alternation of submersion and exposure leads to dynamic changes in the interface albedo α, causing changes in the reflected radiation process and the amount of radiation absorbed at the interface.

[0095] Specifically, at the water-air interface, the heat flux continuity condition is applied, meaning that although the thermal conductivity coefficients of the atmosphere and the water medium differ significantly, the heat flux perpendicular to the interface remains continuous; the formula is as follows:

[0096] ;

[0097] Among them, K a Expressed as atmospheric thermal conductivity, K w Expressed as the thermal conductivity coefficient of water, This is expressed as a vertical temperature gradient; the same heat flux continuity condition applies at the water-soil interface. When considering the abrupt change in heat transfer coefficient at the water-air interface, a discontinuity condition for heat transfer coefficient is applied at the interface. The above equation takes into account the abrupt change in heat transfer coefficient between different media, indicating that the heat flux of the atmosphere and water body is equal at the interface. A similar abrupt change condition for heat transfer coefficient is also applied at the water-soil interface.

[0098] Specifically, the soil thermal conductivity coefficient is calculated dynamically based on the soil volumetric moisture content; the formula for the soil thermal conductivity coefficient is as follows:

[0099] ;

[0100] Among them, K s K represents the calculated soil thermal conductivity coefficient. d Let K represent the thermal conductivity coefficient of dry soil; θ represent the soil volumetric moisture content; and b represent a constant characterizing the influence of soil moisture on the thermal conductivity coefficient. During the soil-air heat exchange process at the time of exposure, changes in soil moisture will affect the soil thermal conductivity coefficient K. sChanges in soil moisture lead to changes in the heat flux at the soil-air interface. There is a significant positive correlation between soil moisture and soil thermal conductivity, which can be extrapolated using this empirical formula.

[0101] The constructed energy balance equations were numerically solved, and the simulation results were verified using observational data.

[0102] Specifically, the water and soil media are vertically stratified and discretized. A finer stratification scheme is used for the water layer and the shallow soil with active heat exchange, while a coarser stratification scheme is used for the deep soil with slow heat exchange. The energy balance control equations are discretized using the implicit difference method, and the discretized numerical model is solved using an iterative method. Because the wetland water layer is shallow and there is significant heat exchange at the interface between the water and soil layers, a finer stratification is used for the water body and shallow soil, while a coarser stratification is used for the deep soil with slow heat exchange. In numerical computation, the control equations are discretized using the implicit difference method, and the numerical model is solved using an iterative method.

[0103] The upper boundary conditions of the energy balance governing equations are jointly determined by the radiation flux absorbed by the surface of the floodplain, the flux exchange between the land surface and the atmosphere, and the energy brought by atmospheric precipitation. According to Fourier's law of heat conduction, the formula for the upper boundary conditions is as follows:

[0104] ;

[0105] ;

[0106] Where Q represents the heat flux entering the interface; d w The diffusion coefficient of water molecules is represented by D(z,t); the turbulent diffusion coefficient of water is represented by T. w The water temperature is represented by z; the water depth is represented by S. n Represented as the net shortwave radiation flux entering the interface; L n L represents the net longwave radiation flux entering the interface. u H is expressed as the long-wavelength radiation flux emitted from the interface. s Expressed as sensible heat flux; L lv E represents the latent heat of vaporization; E represents the evaporation flux.

[0107] The boundary conditions of floodplain wetlands are determined by the radiation flux absorbed by the wetland surface, the flux exchange between the land surface and the atmosphere, and the energy brought by precipitation in the atmosphere.

[0108] The vertical profiles of water temperature, soil temperature, sensible heat flux and latent heat flux measured by wetland observation stations were compared and verified with the corresponding output results of the model; and the Nash efficiency coefficient, coefficient of determination and root mean square error (RMSE) were used as accuracy evaluation indicators.

[0109] This invention provides a technical solution: a method for simulating atmospheric energy exchange in floodplains based on dynamic interface transformation. The method includes the following steps:

[0110] S1. Collect and input the meteorological driving data, hydrological driving data, and underlying surface physical parameters required for model operation. Meteorological driving data includes air temperature, humidity, wind speed, downward shortwave radiation, downward longwave radiation, precipitation, and air pressure. Hydrological driving data includes water depth and soil moisture. Underlying surface physical parameters include albedo, thermal conductivity, extinction coefficient, water surface emissivity, momentum roughness, sensible thermal roughness, and latent heat roughness during both flooding and exposure periods. Thermal conductivity, extinction coefficient, water surface emissivity, momentum roughness, sensible thermal roughness, and latent heat roughness are all key parameters characterizing the physical properties of the underlying surface, used to accurately describe the energy transfer and distribution process at the interface.

[0111] S2. Determine the state of the floodplain wetland interface based on real-time monitoring or simulated inundation depth data; the state includes the inundation period and the exposure period.

[0112] Specifically, the system reads real-time monitoring or simulated flooding depth data for the current calculation period and uses zero-meter water depth as the critical criterion for judgment. If the water depth is greater than 0, the current interface state is determined to be in the flooding period; if the water depth is equal to 0, the current interface state is determined to be in the exposure period.

[0113] S3. Based on the judgment result of the interface state, call the corresponding energy transfer model to simulate the dynamic conversion process of the energy transfer mechanism;

[0114] For example, taking the transition from the exposure period to the inundation period as an example; the soil heat conduction flux at the soil-atmosphere interface at the end of the exposure period is used as the initial condition of the lower boundary of the new water-air interface energy balance equation for the inundation period; the energy balance equation of the overlying water body is constructed and solved; this equation introduces the turbulent diffusion effect and convection mixing effect of the water body; at the same time, the energy balance equation of the bottom saturated soil is constructed and solved.

[0115] For example, taking the transition from the flooding period to the exposure period as an example, the soil heat flux at the water-soil interface at the end of the flooding period is used as the initial condition for the upper boundary of the new soil-atmosphere interface energy balance equation for the exposure period. Simultaneously, the turbulent diffusion and convective mixing terms specific to the water body equation are removed. A soil-atmosphere interface energy balance equation dominated by soil heat conduction is constructed and solved, which incorporates the turbulent exchange effect at the soil-atmosphere interface.

[0116] S4. During the model simulation, key physical processes are executed in real time;

[0117] Specifically, based on the transition of interface state, the albedo is dynamically adjusted to simulate the abrupt change of reflected radiation, and the continuous heat flux transfer process is simulated based on the abrupt change condition of thermal conductivity at the medium interface; when simulating water-air and water-soil composite models, the turbulent diffusion effect and convection mixing effect of water body are introduced; when simulating soil-air dominant model, the turbulent exchange effect of soil-atmosphere interface is introduced, and the dynamic influence of soil moisture on soil thermal conductivity is coupled.

[0118] Specifically, the simulation of abrupt changes in reflected radiation includes dynamically switching the albedo based on the current interface state and adjusting the net longwave radiation flux entering the interface accordingly. The simulation of continuous heat flux transport includes applying heat flux continuity conditions at the water-air and water-soil interfaces to ensure that the heat flux perpendicular to the interface remains continuous despite abrupt changes in the medium's thermal conductivity. The simulation of soil thermal property coupling includes dynamically calculating the soil thermal conductivity based on real-time soil moisture data during the exposure period and coupling the effect of soil moisture on heat transfer capacity.

[0119] S5. Vertically stratify and discretize the water body and soil; use fine stratification for the water layer and active shallow soil, and coarse stratification for the deep soil; use implicit difference method to discretize the energy balance control equation and solve it numerically by iterative method; its upper boundary conditions are jointly determined by surface radiation and energy flux balance.

[0120] S6. The vertical profiles of water temperature, soil temperature, sensible heat flux and latent heat flux measured by wetland observation stations were compared and verified with the corresponding output results of the model; and the Nash efficiency coefficient, the coefficient of determination and the root mean square error (RMSE) were used as accuracy evaluation indicators.

[0121] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation, characterized in that: The method includes: Collect meteorological driving data, hydrological driving data, and underlying surface physical parameters; The state of the floodplain wetland interface is determined based on real-time monitoring or simulated inundation depth data; the state includes the inundation period and the exposure period. Based on the determination of the interface state, the corresponding energy transfer model is called to simulate the dynamic conversion process of the energy transfer mechanism. Specifically, when the interface changes from the exposure period to the submerged period, the energy transfer is simulated to change from the soil-air dominant mode to the water-air and water-soil composite mode. When the interface changes from the submerged period to the exposure period, the energy transfer is simulated to change from the water-air and water-soil composite mode to the soil-air dominant mode. The dynamic conversion process includes: dynamically adjusting the albedo based on the interface state conversion to simulate the abrupt change in reflected radiation; and simulating the continuous heat flux transfer process based on the abrupt change in thermal conductivity at the medium interface. When simulating the water-air and water-soil composite models, the turbulent diffusion effect and convection mixing effect of water are introduced. When simulating the soil-air dominant model, the turbulent exchange effect of the soil-atmosphere interface is introduced, and the dynamic influence of soil moisture on soil thermal conductivity is coupled. The constructed energy balance equations were numerically solved, and the simulation results were verified using observational data.

2. The method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation according to claim 1, characterized in that: The meteorological driving data includes air temperature, humidity, wind speed, downward shortwave radiation, downward longwave radiation, precipitation, and air pressure; the hydrological driving data includes water depth and soil moisture; the underlying surface physical parameters include albedo, thermal conductivity, extinction coefficient, water surface emissivity, momentum roughness, sensible thermal roughness, and latent thermal roughness during the flooding and exposure periods.

3. The method for simulating atmospheric energy exchange in floodplains based on dynamic interface transformation according to claim 1, characterized in that: The determination of the state of the floodplain wetland interface includes judging the inundation depth data of the current calculation period based on a preset critical water depth value. If the floodwater depth data is greater than zero, the current interface state is determined to be in the flooding period; If the submerged water depth data is equal to zero, then the current interface state is determined to be the exposure period.

4. The method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation according to claim 1, characterized in that: The simulation of energy transfer transitioning from a soil-air dominant mode to a water-air and water-soil composite mode when the interface changes from the exposure period to the submersion period includes: When the interface changes from the exposure period to the submerged period, the soil heat conduction flux of the soil-atmosphere interface under the soil-atmosphere dominant mode during the exposure period is used as the lower boundary initial condition of the water-atmosphere interface energy balance equation in the water-atmosphere and water-soil composite modes during the submerged period. An energy balance equation for the interface between the overlying water body and the atmosphere is constructed to simulate the energy transfer process at the water-air interface; the energy balance equation for the interface between the overlying water body and the atmosphere is as follows: ； Among them, T w The water temperature is represented by t; time is represented by z; water depth is represented by A(z); and the lake area at depth z is represented by d. w The diffusion coefficient of water molecules is represented by D(z,t); the turbulent diffusion coefficient of water is represented by c. w φ represents the volumetric heat capacity of the water body; φ represents the heat source term; and Conv represents the convective mixing process term caused by the instability of the density layer structure of the water body.

5. The method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation according to claim 1, characterized in that: The simulation of energy transfer transitioning from a water-air and water-soil composite mode to a soil-air dominant mode when the interface changes from a flooded period to an exposed period includes: When the interface changes from the flooding period to the exposure period, the soil heat flux of the water-soil interface under the water-air and water-soil composite modes during the flooding period is used as the upper boundary initial condition of the soil-atmosphere interface energy balance equation under the soil-air dominant mode during the exposure period, and the turbulent diffusion effect term and the convection mixing effect term contained in the energy balance equation of the overlying water body during the flooding period are removed. An energy balance equation for the soil-atmosphere interface, primarily based on soil heat conduction, is constructed to simulate the energy transfer process at the soil-atmosphere interface. The soil-atmosphere interface energy balance equation is as follows: ； Among them, T s This is expressed as the bottom soil temperature; d s c represents the molecular diffusion coefficient of the bottom soil layer. s The volumetric heat capacity of the bottom soil layer is represented by t; time is represented by z; water depth is represented by φ; and the heat source term is represented by Q. s-a It is expressed as the turbulent exchange flux at the soil-atmosphere interface.

6. The method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation according to claim 1, characterized in that: The dynamic adjustment of albedo based on interface state transitions to simulate abrupt changes in reflected radiation includes: The net longwave radiation flux entering the interface is corrected by the change in the dynamic interface albedo; the net longwave radiation flux is the difference between the net surface radiation and the downward shortwave radiation reflected by the interface, as shown in the following formula: ； Among them, L n Represented as the net longwave radiation flux entering the interface; R n This is expressed as net surface radiation. It is represented as downward shortwave radiation; α is the albedo under the current interface state.

7. The method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation according to claim 1, characterized in that: The simulation of the continuous heat flux transport process based on the abrupt change in thermal conductivity at the medium interface includes: At the water-air interface, the heat flux continuity condition is applied, meaning that although the thermal conductivity coefficients of the atmosphere and the water medium differ significantly, the heat flux perpendicular to the interface remains continuous; the formula is as follows: ； Among them, K a Expressed as atmospheric thermal conductivity, K w Expressed as the thermal conductivity coefficient of water, It is represented as a vertical temperature gradient; the same heat flux continuity condition is applied at the water-soil interface.

8. The method for simulating atmospheric energy exchange in floodplain wetlands based on dynamic interface transformation according to claim 1, characterized in that: The dynamic influence of coupled soil moisture on the soil thermal conductivity includes: The soil thermal conductivity coefficient is calculated dynamically based on the soil volumetric moisture content; the formula for the soil thermal conductivity coefficient is as follows: ； Among them, K s K represents the calculated soil thermal conductivity coefficient. d θ represents the thermal conductivity coefficient of dry soil; θ represents the soil volumetric moisture content; and b represents a constant characterizing the influence of soil moisture on the thermal conductivity coefficient.

9. The method for simulating atmospheric energy exchange in floodplains based on dynamic interface transformation according to claim 1, characterized in that: The process of numerically solving the constructed energy balance equation and verifying the simulation results using observational data includes: The water and soil media are vertically stratified and discretized; a fine stratification scheme is used for the water layer and the shallow soil with active heat exchange, while a coarse stratification scheme is used for the deep soil with slow heat exchange; the energy balance equation is discretized using the implicit difference method, and the discretized numerical model is solved by the iterative method. The vertical profiles of water temperature, soil temperature, sensible heat flux and latent heat flux measured by wetland observation stations were compared and verified with the corresponding output results of the model; and the Nash efficiency coefficient, coefficient of determination and root mean square error (RMSE) were used as accuracy evaluation indicators.

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