Photovoltaic area evapotranspiration inversion method and system

Abstract

The invention discloses a photovoltaic region evapotranspiration inversion method and system, and relates to the technical field of photovoltaic power generation, and the method comprises the following steps: obtaining the photovoltaic power generation efficiency through the area proportion of a non-photovoltaic panel region and the surface temperature of a target photovoltaic region; the instantaneous net radiation in the SEBS model is corrected through the area proportion of the non-photovoltaic panel area and the photovoltaic power generation efficiency, and the instantaneous soil heat flux in the SEBS model is corrected through the corrected instantaneous net radiation of the photovoltaic area and the canopy coverage rate; correcting atmospheric sensible heat under dry pole and wet pole conditions in the SEBS model through the corrected soil heat flux and photovoltaic area instantaneous net radiation; and calculating daily evapotranspiration based on the corrected instantaneous net radiation of the photovoltaic area, the soil heat flux, and the atmospheric sensible heat and the instantaneous net radiation of the photovoltaic area under the dry pole and wet pole conditions. According to the method, the photovoltaic power generation efficiency model and the remote sensing evapotranspiration inversion model SEBS are coupled, and the change of the photovoltaic module on the energy income and expenditure is considered, so that the systematic error is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation technology, and in particular to a method and system for inverting evapotranspiration in a photovoltaic region. Background Technology

[0002] With the continuous development and large-scale deployment of photovoltaic (PV) power plants globally, people are increasingly concerned about their potential impacts on regional climate, hydrological cycles, and ecosystems. Large-area PV panels alter the underlying surface properties, affecting the energy balance between the surface and atmosphere (such as albedo and heat capacity), water exchange, and wind speed profiles, thus impacting local microclimates and the ecological environment. Evapotranspiration (ET) is a key link and important indicator of the hydrological cycle and surface energy balance; accurate ET inversion can quantify the actual water consumption of a region. By comparing the ET of the PV area with that of the surrounding natural surface (without PV panels), it is possible to scientifically assess whether the establishment of PV power plants exacerbates local drought or conserves soil moisture through the shading effect. Therefore, conducting surface evapotranspiration inversion in PV areas is crucial for evaluating the comprehensive ecological benefits of PV projects.

[0003] Traditional energy exchange (ET) observations rely heavily on ground-based monitoring methods such as eddy covariance and lysimeters. These technologies provide high-precision measured data at the point scale, which is valuable for studies of specific experimental plots or small areas. However, due to their high cost, long observation period, and limited spatial coverage, they are insufficient to meet the large-scale, long-term dynamic monitoring needs in the context of widespread photovoltaic power plants. Compared to traditional methods, remote sensing technology can rapidly and comprehensively acquire surface information, simultaneously capturing the spatiotemporal changes of vegetation, soil, water bodies, and other surface elements, providing crucial support for studying the energy exchange characteristics of the region. For example, based on medium- and high-resolution remote sensing data such as Landsat, MODIS, and Sentinel, key parameters such as surface temperature, albedo, and vegetation indices can be retrieved. Building upon this foundation, remote sensing ET inversion models such as SEBAL (Surface Energy Balance Algorithm for Land), SEBS (Surface Energy Balance System), METRIC (Mapping Evapotranspiration at High Resolution with Internalized Calibration), and Penman-Monteith are used to estimate ET at regional and even global scales, quantitatively characterizing the spatial pattern and seasonal dynamics of regional ET. However, these inversion models are designed based on uniform and continuous natural surfaces (such as farmland, grassland, and water bodies). Photovoltaic power plants and shading by photovoltaic panels alter the surface characteristics, thereby changing the surface energy distribution and posing a significant challenge to remote sensing ET inversion in photovoltaic areas. Furthermore, in photovoltaic power plant areas, the arrangement of photovoltaic panels generates complex and dynamically moving shadows, leading to uneven solar radiation received by the surface. The shading effect of photovoltaic panels poses a significant challenge to ET inversion.

[0004] In summary, existing technologies still have significant shortcomings in evapotranspiration inversion studies of photovoltaic (PV) areas. First, current research on evapotranspiration (ET) in PV areas largely relies on ground-based observation methods, requiring long-term field experiments and continuous observation to accumulate high-precision data. While this approach offers high accuracy, it is time-consuming, inefficient, and costly, and makes it difficult to systematically assess the environmental effects of large-scale, long-term PV power plants. Second, existing ET-based remote sensing inversion studies are mostly concentrated on bare surfaces or vegetated areas, with relatively few studies on surfaces with complex shading mechanisms (such as large-scale PV power plant areas). The surface energy balance in these areas is significantly affected by the shading effect and energy output of PV panels. Directly applying existing remote sensing ET-based models without considering the changes in surface energy balance caused by PV power generation will inevitably lead to significant systematic errors. Summary of the Invention

[0005] In view of the defects of the existing technology, the present invention provides a photovoltaic region evapotranspiration inversion method and system, which solves the existing problems.

[0006] The present invention adopts the following technical solution: In a first aspect, the present invention provides a method for inverting evaporation in a photovoltaic region, comprising the following steps: Acquire data on the proportion of non-photovoltaic panel areas, surface temperature, and remote sensing imagery of the target photovoltaic area; The photovoltaic panel temperature is obtained by measuring the area ratio of non-photovoltaic panel areas and the surface temperature of the target photovoltaic area. The photovoltaic panel temperature is then input into the photovoltaic power generation efficiency model to obtain the photovoltaic power generation efficiency. The SEBS model is constructed based on remote sensing image data of the target photovoltaic area. The instantaneous net radiation in the SEBS model is corrected by the proportion of non-photovoltaic panel area and photovoltaic power generation efficiency. The instantaneous soil heat flux in the SEBS model is corrected by the corrected instantaneous net radiation of the photovoltaic area and the canopy coverage. The atmospheric sensible heat under dry and wet conditions in the SEBS model is corrected by the corrected soil heat flux and instantaneous net radiation of the photovoltaic area. The evaporation ratio is calculated based on the modified instantaneous net radiation of the photovoltaic area, soil heat flux, atmospheric sensible heat under dry and wet conditions, and instantaneous net radiation of the photovoltaic area. Daily evapotranspiration is then calculated using the evaporation ratio.

[0007] Preferably, obtaining the area ratio of non-photovoltaic panel areas in the target photovoltaic area specifically includes the following steps: Based on the latitude of the target photovoltaic area, the maximum efficiency and loss empirical parameters of the photovoltaic panels are obtained. The maximum efficiency and loss empirical parameters are fitted to obtain the ratio of photovoltaic panel length to photovoltaic panel spacing. The optimal tilt angle of the photovoltaic panels for the year is obtained based on the latitude of the target photovoltaic area; The proportion of non-photovoltaic panel area in the target photovoltaic zone is obtained based on the ratio of photovoltaic panel length to photovoltaic panel spacing and the optimal annual tilt angle of the photovoltaic panels.

[0008] Preferably, the specific proportion of the non-photovoltaic panel area in the target photovoltaic area is as follows: ; In the formula, The area represents the proportion of non-photovoltaic panel areas, and GCR is the ratio of photovoltaic panel length to photovoltaic panel spacing. The angle at which the photovoltaic panel is tilted.

[0009] Preferably, the photovoltaic panel temperature is as follows: ; In the formula, For the temperature of the photovoltaic panel, This represents the percentage of non-photovoltaic panel area. The surface temperature of the target photovoltaic area. This refers to the surface temperature in the interplate zone.

[0010] Preferably, the instantaneous net radiation is as follows: ; In the formula, This refers to the instantaneous net radiation at the Earth's surface. For surface reflectance, For incident shortwave radiation, This represents the percentage of non-photovoltaic panel area. For the power generation efficiency of photovoltaics, For long-wave radiation to reach the Earth's surface, Long-wave radiation emitted by the Earth's surface itself. This is part of the atmospheric back radiation reflected from the Earth's surface.

[0011] Preferably, the instantaneous soil heat flux is as follows: ; In the formula, G is the instantaneous soil heat flux. Canopy coverage.

[0012] Preferably, the atmospheric sensible heat under dry and wet electrode conditions is as follows: ; ; In the formula, H dry This refers to atmospheric sensible heat under dry polar conditions. H wet This refers to atmospheric sensible heat under extremely humid conditions. air density, The specific heat of air at constant pressure. This refers to the aerodynamic drag coefficient under humid and hot conditions. The saturated vapor pressure, This is the actual water vapor pressure. This is the hygrometer constant. This represents the slope of the saturated vapor pressure versus temperature curve.

[0013] Preferably, the evaporation ratio is as follows: ; ; In the formula, The latent heat flux ratio, The latent heat of vaporization of water, Latent heat flux; Let H be the latent heat flux under humid conditions, and H be the atmospheric sensible heat. This represents the evaporation ratio.

[0014] Preferably, the daily evapotranspiration is specifically as follows: ; In the formula, ET 24 Evaporation by the sun G 24 This represents the soil heat flux over a 24-hour period. R n24 This is the average daily net radiation.

[0015] Secondly, the present invention provides a photovoltaic area surface evapotranspiration inversion system, comprising: The acquisition module is used to acquire the area ratio of non-photovoltaic panel areas, surface temperature, and remote sensing image data of the target photovoltaic area. The first calculation module is used to obtain the photovoltaic panel temperature by the proportion of non-photovoltaic panel area and the surface temperature of the target photovoltaic area, and input the photovoltaic panel temperature into the photovoltaic power generation efficiency model to obtain the photovoltaic power generation efficiency. The correction module is used to construct an SEBS model based on remote sensing image data of the target photovoltaic area. It corrects the instantaneous net radiation in the SEBS model by the proportion of non-photovoltaic panel area and photovoltaic power generation efficiency, corrects the instantaneous soil heat flux in the SEBS model by the corrected instantaneous net radiation of the photovoltaic area and canopy coverage, and corrects the atmospheric sensible heat under dry and wet conditions in the SEBS model by the corrected soil heat flux and instantaneous net radiation of the photovoltaic area. The second calculation module is used to calculate the evaporation ratio based on the corrected instantaneous net radiation of the photovoltaic area, soil heat flux, and atmospheric sensible heat and instantaneous net radiation of the photovoltaic area under dry and wet conditions, and to calculate the daily evapotranspiration through the evaporation ratio.

[0016] Compared with the prior art, the above-mentioned at least one technical solution adopted by the present invention can achieve the following beneficial effects: This invention obtains photovoltaic (PV) panel temperature based on the area ratio of non-PV panel areas in a target PV zone, and inputs the PV panel temperature into a PV power generation efficiency model to obtain the PV power generation efficiency. This invention uses surface temperature data combined with the structural characteristics of the PV zone to correct the PV panel temperature, thus more accurately characterizing the thermal properties of the PV panels. Then, it corrects the instantaneous net radiation, instantaneous soil heat flux, and atmospheric sensible heat under dry and wet pole conditions in the SEBS model by using the area ratio of non-PV panel areas and PV power generation efficiency. Based on the corrected instantaneous net radiation, soil heat flux, and atmospheric sensible heat under dry and wet pole conditions, and the instantaneous net radiation of the PV zone, the evaporation ratio is calculated, and daily evapotranspiration is calculated using the evaporation ratio. This invention corrects the net radiation, atmospheric sensible heat, soil heat flux, and latent heat of evaporation through the PV efficiency model, achieving a physically consistent characterization of the evapotranspiration process under the complex underlying surface conditions of the PV zone. By coupling the PV power generation efficiency model with the remote sensing evapotranspiration inversion model SEBS, this invention considers the changes in energy budget caused by PV modules, thereby compensating for the shortcomings of a single remote sensing inversion method in PV zone applications and greatly reducing systematic errors. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the shielding area and the gap area of ​​the present invention; Figure 2 This is a top view of the photovoltaic area of ​​the present invention; Figure 3 This is a side view of the photovoltaic region of the present invention; Figure 4 This is a flowchart of a photovoltaic region evaporation inversion method according to the present invention. Detailed Implementation

[0019] 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.

[0020] Example 1 This invention proposes a remote sensing inversion method for evapotranspiration in photovoltaic (PV) areas based on a combination of the SEBS model and a PV efficiency model. First, vector data on the distribution of PV power plant construction across the country is acquired, and PV sites within a certain range are merged into PV clusters to avoid insufficient inversion accuracy due to the small size of individual PV areas. Then, diurnal data on meteorological elements, altitude, albedo, and surface temperature provided by the MODIS satellite dataset and the Tibetan Plateau Data Center are used as input parameters for the SEBS model. The area ratio of PV panels within each PV area is calculated using the optimal efficiency modeling method (Equation 3). Combined with the PV power generation efficiency model, the power generation efficiency of the PV power plant is obtained. Based on this, the net radiation term of the SEBS model is reconstructed, and the soil heat flux is corrected, ultimately achieving coupling between the PV power generation efficiency model and the SEBS model, and thus calculating the annual ET results for each PV area nationwide. (Refer to...) Figure 4 The present invention specifically includes the following steps:

[0021] S1: Determine the target photovoltaic area for the study, obtain its vector boundary map through satellite means, and directly obtain the tilt angle of the photovoltaic panels and the area ratio of non-photovoltaic panel areas within the photovoltaic area based on the ultra-high resolution vector boundary map.

[0022] If it cannot be obtained directly, it can be calculated using the empirical formula for the optimal tilt angle and the expression for the optimal area ratio.

[0023] Reference Figure 2 and Figure 3 The specific proportion of non-photovoltaic panel areas in the photovoltaic zone is as follows: (1); The empirical formula for the optimal annual tilt angle based on latitude is: (2); In the formula, Let be the tilt angle of the photovoltaic panel, and be the angle between the photovoltaic panel and the ground plane. ; Latitude .

[0024] The empirical formula for the optimal area proportion below 75° North latitude is: GCR (Ground Coverage Ratios) Calculation Parameter Selection Diagram (3); In the formula, This is the ratio of the length of the photovoltaic panel to the spacing between the photovoltaic panels. All of these are fitting parameters.

[0025] The percentage of non-photovoltaic panel area is obtained based on the size and spacing information of the photovoltaic panels: (4); In the formula, The length of the photovoltaic panel, The spacing between the two rows of photovoltaic panels. This refers to the number of rows of photovoltaic panels.

[0026] Under normal circumstances Larger, and It is not much different from R, therefore The area ratio of non-photovoltaic panel areas within the photovoltaic zone is shown below: (5); Modeling of shading and gap areas in photovoltaic (PV) systems: Utilizing a model based on the optimal efficiency of the PV panel gap spacing, suitable parameters are quickly selected using previously provided empirical parameters. The proportion of non-PV panel area is calculated, assuming a uniform distribution of shading areas within each grid. Based on this proportion, the gap and shading areas are quantified, enabling the modeling of an energy balance model for these areas. Figure 1 As shown.

[0027] S2: Obtain the photovoltaic panel temperature by using the area ratio of non-photovoltaic panel areas and the surface temperature of the target photovoltaic area. Input the photovoltaic panel temperature into the photovoltaic power generation efficiency model (Formula 6) to obtain the photovoltaic power generation efficiency.

[0028] To address the challenge of obtaining photovoltaic (PV) operation data for different regions in large-scale PV regional studies, this invention fully leverages the accessibility and spatial continuity of remote sensing data. The specific approach is as follows: First, the study area is divided into PV panel areas and non-PV panel areas, and the relationship between the two is quantified through area proportions. Then, remote sensing surface temperature data, combined with analysis of the buffer zone (the area surrounding the PV panel area), is used to estimate the actual operating temperature of the PV panels, and subsequently, the PV power generation efficiency is calculated.

[0029] Calculation of photovoltaic power generation efficiency: (6); In the formula, The panel is at the reference temperature Reference efficiency at that time The change in panel efficiency is caused by changes in panel temperature. At that time, it is assumed that the relationship is valid. This refers to the temperature of the photovoltaic panel. However, due to the mixed pixels, it is assumed that the surface temperature data for the photovoltaic area is sufficient. LST equal , This refers to the percentage of non-photovoltaic panel area within the photovoltaic zone; Given the surface temperature in the plate-plate gap region, calculated using the average surface temperature of the buffer zone, we can obtain:

[0030] (7); S3: Download meteorological raster data for the study area, including daily meteorological data, surface temperature data, surface albedo data, and elevation data (DEM). Daily meteorological data includes daily 2m maximum temperature, minimum temperature, average temperature, average wind speed, relative humidity, sunshine duration, and surface pressure. Construct an SEBS model based on remote sensing image data of the target photovoltaic area.

[0031] The instantaneous net radiation of the photovoltaic area in the SEBS model is corrected by the proportion of non-photovoltaic panel area and photovoltaic power generation efficiency. The instantaneous soil heat flux in the SEBS model is corrected by the corrected instantaneous net radiation of the photovoltaic area and canopy coverage. The atmospheric sensible heat under dry and wet conditions in the SEBS model is corrected by the corrected soil heat flux and instantaneous net radiation of the photovoltaic area.

[0032] S31: Calculation of average daily net radiation in the target photovoltaic area: (8); (9); (10); (11); (12); (13); (14); (15); In the formula, R n24 The average daily net radiation, , It refers to the surface reflectance (albedo). For incident shortwave radiation, ; The photovoltaic power generation efficiency is calculated using the photovoltaic efficiency formula. R nl For effective longwave radiation on the Earth's surface, ; , This is a regression constant, which is region-dependent. If there is no fixed value, 0.25 is acceptable. 0.50 is acceptable; This represents the theoretical solar radiation at the top of the atmosphere. ; The solar constant is taken as 1367. ; It is the reciprocal of the Earth-Sun astronomical unit distance; Solar hour angle, ; Solar declination angle ; Latitude, rad The highest thermodynamic temperature of the day. ; The lowest thermodynamic temperature of the day. ; The measured water vapor pressure ( ); For relatively shortwave radiation (limited to no more than 1.0); To calculate the clear-sky radiation, ; For altitude, ; When the time is in day order and the month is the unit of calculation, , For the order of months; The actual sunshine duration, in hours (h). Theoretical sunshine hours, ; This refers to the relative sunshine duration.

[0033] S32: Calculation of instantaneous net radiation using remote sensing data; calculation of instantaneous net radiation of the target photovoltaic area: (16); (17); (18); (19); In the formula, This refers to the instantaneous net radiation at the Earth's surface. ; Surface reflectance; For incident shortwave radiation, ; This represents the area ratio of non-photovoltaic panel areas, assumed to be the optimal coverage rate with the highest power generation efficiency. The photovoltaic power generation efficiency is calculated using the photovoltaic efficiency formula. For long-wave radiation to reach the Earth's surface, ; Long-wave radiation emitted by the Earth's surface itself. ; This is part of the atmospheric back radiation reflected from the Earth's surface. ; Here is the Stefan Boltzmann constant, and its value is... ; Atmospheric emissivity; The surface emissivity is 0.9, which is taken as the shading value from the photovoltaic panels. For reference altitude air temperature, K In this calculation, 2m is selected; For grid surface temperature, .

[0034] Calculation of atmospheric one-way transmittance: (20); Calculation of atmospheric emissivity: (twenty one); Incident shortwave radiation: (twenty two); In the formula, The solar constant has a value of 1367. , This is the solar zenith angle.

[0035] S33: Calculation of instantaneous soil heat flux based on instantaneous net radiation in photovoltaic areas: (twenty three); In the formula, The canopy coverage rate is assumed to be equal to the photovoltaic coverage rate because the photovoltaic panels shade the vegetation, making it impossible to directly observe the vegetation under the photovoltaic panels. Furthermore, the original vegetation in photovoltaic areas is usually cleared, so the photovoltaic panels after construction can be treated as a vegetation canopy.

[0036] S34: The final atmospheric sensible heat is obtained by calculating the dry and wet pole conditions in the SEBS model and then correcting them.

[0037] atmospheric thermal This refers to the portion of energy lost into the atmosphere due to conduction and convection. It is a function of atmospheric stability, wind speed, and surface roughness, and its calculation formula is: (twenty four); (25); In the formula: air density, ; For the specific heat of air at constant pressure, take ; The temperature difference between the two altitudes. ; For aerodynamic drag, ; For air temperature, ; For altitude, .

[0038] Calculate aerodynamic drag ,Right now: (26); in, The value is usually slightly higher than the average height of the vegetation canopy. The value is taken slightly lower than the boundary layer height; in practical applications, it is generally taken as... , ; For frictional wind speed, ; This is the Karman constant, with a value of 0.41.

[0039] The spatial distribution of frictional wind speed is calculated based on the wind profile relationship of a stable surface. The wind profile relationship of a stable surface is as follows: (27); in, For height Wind speed at the location, ; For the surface roughness of momentum transport, since the traditional empirical formula for NDVI cannot be used in the photovoltaic coverage area, a medium-roughness artificial ground is adopted, which is 0.15m.

[0040] Because surface heating leads to an unstable near-surface atmosphere, SEBS applies the Monin-Obukhov similarity theory and introduces stability correction factors for atmospheric heat and momentum transport. and And calculate the length of Monin-Obukhov. L Regarding aerodynamic drag After correction, iterative solution. . and The specific calculation method is as follows:

[0041] (28); (10) ,steady state: (29); (11) Unstable state: (30); (31); (32); (12) Neutral state: (33); In the formula: Let be the acceleration due to gravity, and take . ; for The height parameter; the meanings of the other symbols are the same as before.

[0042] Will , , Substituting into the following formula, for Perform corrections.

[0043] (34); (35); Repeat the above correction steps until a stable atmospheric sensible heat is obtained. .

[0044] Atmospheric sensible heat calculation under dry polar conditions: (36); Atmospheric sensible heat calculation under humid conditions: (37); (38); (39); In the formula, This represents the aerodynamic drag coefficient under humid and hot conditions. It is the saturated vapor pressure; This is the actual water vapor pressure; This is the hygrometer constant; The slope of the saturated vapor pressure versus temperature curve; Monin-Obukhov length under humid and hot conditions L ; Let be the latent heat of vaporization of water, and be a temperature-dependent function. .

[0045] S4: Calculate the evaporation ratio based on the corrected instantaneous net radiation of the photovoltaic area, soil heat flux, and atmospheric sensible heat under dry and wet polar conditions, and calculate the daily evapotranspiration using the evaporation ratio. Evaporation ratio calculation: (40); (41); In the formula, The latent heat flux ratio; Latent heat flux; This represents the latent heat flux under wet polar conditions.

[0046] Step 6: Calculate the daily evapotranspiration ET. The soil heat flux is almost zero during the day, so the average daily soil heat flux is 0.

[0047] (42); In the formula, G 24 This represents the soil heat flux over a 24-hour period.

[0048] This model is mainly for calculating evapotranspiration (ET) on a daily scale. For monthly and annual scales, it can be accumulated. In the calculation, the entire photovoltaic area can be considered as a whole and the average value can be taken. Alternatively, individual grid points can be resolved and inverted, and then summed to represent the evapotranspiration of the entire photovoltaic area. This method is a theoretical physical model, and some of the parameters are suggestions for reference. It is designed for inversion based on easily obtainable remote sensing data. If more specific and detailed data is available, its inversion accuracy will be improved.

[0049] Example 2 Based on the same concept, the present invention also provides a photovoltaic area surface evapotranspiration inversion system, including an acquisition module, a first calculation module, a correction module, and a second calculation module.

[0050] The acquisition module is used to acquire the area ratio of non-photovoltaic panel areas, surface temperature, and remote sensing image data of the target photovoltaic area.

[0051] The first calculation module is used to obtain the photovoltaic panel temperature by using the proportion of non-photovoltaic panel area and the surface temperature of the target photovoltaic area, and input the photovoltaic panel temperature into the photovoltaic power generation efficiency model to obtain the photovoltaic power generation efficiency.

[0052] The correction module is used to construct an SEBS model based on remote sensing image data of the target photovoltaic area. It corrects the instantaneous net radiation in the SEBS model by the proportion of non-photovoltaic panel area and photovoltaic power generation efficiency, corrects the instantaneous soil heat flux in the SEBS model by the corrected instantaneous net radiation of the photovoltaic area and canopy coverage, and corrects the atmospheric sensible heat under dry and wet conditions in the SEBS model by the corrected soil heat flux and instantaneous net radiation of the photovoltaic area.

[0053] The second calculation module is used to calculate the evaporation ratio based on the corrected instantaneous net radiation of the photovoltaic area, soil heat flux, and atmospheric sensible heat and instantaneous net radiation of the photovoltaic area under dry and wet conditions, and to calculate the daily evapotranspiration through the evaporation ratio.

[0054] This invention first selects multi-source remote sensing data that meets the spatiotemporal resolution requirements based on research needs and time series characteristics, and acquires daily-scale meteorological observation data and spatial layout information of photovoltaic power plants in the study area. Subsequently, this multi-source data is input into the SEBS model to conduct remote sensing ET inversion, and coupled with an improved photovoltaic power generation efficiency model. During this process, the photovoltaic panel temperature, which needs to be calculated in the model, is corrected using remotely sensed surface temperature data combined with the structural characteristics of the photovoltaic area, thereby more accurately characterizing the thermal properties of the photovoltaic panels. Finally, an energy balance coupling model suitable for the complex underlying surface of the photovoltaic area is constructed, realizing the inversion of daily-scale ET in the photovoltaic power plant area. This method provides a new technical approach for quantitatively assessing the impact of photovoltaic construction on regional energy and water cycles.

[0055] Assuming the evaporation ratio remains constant throughout the day and the daily soil heat flux is 0, the daily net radiation is incorporated to obtain the ET for that day, and finally the annual evapotranspiration of each photovoltaic region across the country is accumulated.

[0056] Compared to the traditional SEBAL model, the SEBS model does not require the selection of wet and dry points. However, in photovoltaic (PV) areas, the selection of wet and dry points is often difficult due to the shading effect of PV panels. Therefore, the SEBS model can effectively overcome this difficulty. Addressing the lack of high-time-series efficiency data in PV areas under normal circumstances, this invention improves some parameters of the SEBS model and introduces a PV efficiency model to correct the net radiation term, making the model more reasonable in its physical process representation, as well as simpler and more efficient. Furthermore, for areas lacking data on the area ratio of PV panels, this invention proposes a compensation method, which, under ideal conditions, introduces the maximum efficiency parameter of the PV panels and a moderate loss coefficient to calculate the PV area ratio.

[0057] In summary, this invention, while retaining the physical foundation of SEBS, combines a photovoltaic efficiency correction mechanism to improve the applicability and physical reliability of the ET inversion model for photovoltaic areas, and provides a feasible method for studying the impact of large-scale, multi-regional photovoltaic area construction.

[0058] This invention constructs a remote sensing ET inversion method for photovoltaic areas that couples remote sensing data with a physical model. First, the required remote sensing data is downloaded through the GEE (Google Earth Engine) platform or the National Tibetan Plateau Scientific Data Center. Leveraging the continuous and rapid spatiotemporal coverage of remote sensing data, key surface parameters of the photovoltaic area are obtained, such as surface temperature (LST), albedo, vegetation index (NDVI), and meteorological data including 2m maximum, minimum, and average temperatures, average wind speed, relative humidity, sunshine duration, and surface pressure. These variables directly reflect the differences in energy exchange and water cycle between the photovoltaic panel-covered area and the surrounding environment. However, relying solely on remote sensing data has limitations, especially in cases of missing surface information due to photovoltaic panel shading and increased heterogeneity of the underlying surface. Simple remote sensing data inversion cannot accurately characterize the actual evapotranspiration process. Therefore, this invention further introduces two physical models: a photovoltaic power generation efficiency model and a SEBS model, to supplement the remote sensing observation data with physical constraints and mechanistic processes. The physical models rationally decompose net radiation, atmospheric sensible heat (sensible heat flux), soil heat flux, and latent heat of evaporation. This approach achieves a physically consistent characterization of evapotranspiration processes under complex underlying surface conditions in photovoltaic (PV) areas. Simultaneously, by coupling the PV power generation efficiency model with the SEBS remote sensing evapotranspiration inversion model, the changes in energy budget caused by PV modules are considered, such as the correction of surface energy balance and evapotranspiration processes by shading effects. This compensates for the shortcomings of using a single remote sensing inversion method in PV areas. This synergistic "remote sensing + model" approach ensures both the broad coverage and high frequency advantages of remote sensing observations at the regional scale, and enhances the mechanistic rationality under complex underlying surface conditions through physical models. It can reveal the long-term impacts of PV power plant construction on local hydrological cycles and ecological processes at the regional scale, providing scientific support for assessing the regional climate and ecological environmental effects of PV development.

[0059] This invention modifies and improves the photovoltaic power generation efficiency model, making it more suitable for multi-regional and multi-scale evapotranspiration inversion and energy balance analysis. During model construction, considering the wide distribution and significant regional differences of photovoltaic power plants, the parameterization method of the original photovoltaic power generation efficiency model was optimized to enhance its applicability and stability in different regions. Furthermore, considering the lack of fine parameters such as the proportion of photovoltaic panel gap area and tilt angle in practical applications, this study introduces empirical formulas as a supplement to improve the model's robustness and operability under conditions of missing or incomplete data. This improvement not only enhances the model's universality under large-scale and multi-regional conditions but also provides more reliable technical support for the refined inversion of evapotranspiration in photovoltaic areas and the study of hydrological processes.

[0060] This invention combines a photovoltaic (PV) power generation efficiency model with the SEBS (Surface Energy Balance System) model to propose an evapotranspiration (ET) inversion method suitable for PV areas. This method fully leverages the advantage of the SEBS model, which eliminates the need to select wet and dry points in energy balance calculations, effectively overcoming the applicability limitations of remote sensing data under PV panel shading conditions. Simultaneously, this study modifies and improves the key parameterization process of the SEBS model, making it more consistent with the underlying surface characteristics and energy exchange mechanisms of PV power plant areas, thereby enhancing the model's applicability and accuracy in PV scenarios. Through this innovative coupling framework, this invention fills the research gap in using remote sensing data for ET inversion of PV areas, providing a new technical approach and scientific support for quantifying the impact of PV power plant construction on local hydrological cycles and the ecological environment.

[0061] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0062] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for inverting evaporation in a photovoltaic region, characterized in that, Includes the following steps: Acquire data on the proportion of non-photovoltaic panel areas, surface temperature, and remote sensing imagery of the target photovoltaic area; The photovoltaic panel temperature is obtained by measuring the area ratio of non-photovoltaic panel areas and the surface temperature of the target photovoltaic area. The photovoltaic panel temperature is then input into the photovoltaic power generation efficiency model to obtain the photovoltaic power generation efficiency. The SEBS model is constructed based on remote sensing image data of the target photovoltaic area. The instantaneous net radiation in the SEBS model is corrected by the proportion of non-photovoltaic panel area and photovoltaic power generation efficiency. The instantaneous soil heat flux in the SEBS model is corrected by the corrected instantaneous net radiation of the photovoltaic area and the canopy coverage. The atmospheric sensible heat under dry and wet conditions in the SEBS model is corrected by the corrected soil heat flux and instantaneous net radiation of the photovoltaic area. The evaporation ratio is calculated based on the modified instantaneous net radiation of the photovoltaic area, soil heat flux, atmospheric sensible heat under dry and wet conditions, and instantaneous net radiation of the photovoltaic area. Daily evapotranspiration is then calculated using the evaporation ratio.

2. The photovoltaic region evapotranspiration inversion method as described in claim 1, characterized in that, The process of obtaining the area ratio of non-photovoltaic panel areas in the target photovoltaic area specifically includes the following steps: Based on the latitude of the target photovoltaic area, the maximum efficiency and loss empirical parameters of the photovoltaic panels are obtained. The maximum efficiency and loss empirical parameters are fitted to obtain the ratio of photovoltaic panel length to photovoltaic panel spacing. The optimal tilt angle of the photovoltaic panels for the year is obtained based on the latitude of the target photovoltaic area; The proportion of non-photovoltaic panel area in the target photovoltaic zone is obtained based on the ratio of photovoltaic panel length to photovoltaic panel spacing and the optimal annual tilt angle of the photovoltaic panels.

3. The photovoltaic region evapotranspiration inversion method as described in claim 2, characterized in that, The specific proportion of the non-photovoltaic panel area in the target photovoltaic zone is shown below: ； In the formula, The area represents the proportion of non-photovoltaic panel areas, and GCR is the ratio of photovoltaic panel length to photovoltaic panel spacing. The angle at which the photovoltaic panel is tilted.

4. The photovoltaic region evapotranspiration inversion method as described in claim 1, characterized in that, The specific temperatures of the photovoltaic panels are shown below: ； In the formula, For the temperature of the photovoltaic panel, This represents the percentage of non-photovoltaic panel area. The surface temperature of the target photovoltaic area. This refers to the surface temperature in the interplate zone.

5. The photovoltaic region evapotranspiration inversion method as described in claim 1, characterized in that, The instantaneous net radiation is as follows: ； In the formula, The instantaneous net radiation at the Earth's surface. For surface reflectance, For incident shortwave radiation, This represents the percentage of non-photovoltaic panel area. For the power generation efficiency of photovoltaics, For long-wave radiation to reach the Earth's surface, Long-wave radiation emitted by the Earth's surface itself. This is part of the atmospheric back radiation reflected from the Earth's surface.

6. The photovoltaic region evapotranspiration inversion method as described in claim 5, characterized in that, The instantaneous soil heat flux is specifically shown below: ； In the formula, G is the instantaneous soil heat flux. Canopy coverage.

7. The photovoltaic region evapotranspiration inversion method as described in claim 6, characterized in that, The atmospheric sensible heat under dry and wet electrode conditions is shown below: ； ； In the formula, H dry This refers to atmospheric sensible heat under dry polar conditions. H wet This refers to atmospheric sensible heat under extremely humid conditions. air density, The specific heat of air at constant pressure. This refers to the aerodynamic drag coefficient under humid and hot conditions. The saturated vapor pressure, This is the actual water vapor pressure. This is the hygrometer constant. This represents the slope of the saturated vapor pressure versus temperature curve.

8. The photovoltaic region evapotranspiration inversion method as described in claim 7, characterized in that, The evaporation ratio is specifically as follows: ； ； In the formula, The latent heat flux ratio, The latent heat of vaporization of water, Latent heat flux; Let H be the latent heat flux under humid conditions, and H be the atmospheric sensible heat. This represents the evaporation ratio.

9. The photovoltaic region evapotranspiration inversion method as described in claim 8, characterized in that, The specific details of the diurnal evapotranspiration are as follows: ； In the formula, ET 24 Evaporation by the sun G 24 This represents the soil heat flux over a 24-hour period. R n24 This is the average daily net radiation.

10. A photovoltaic area surface evapotranspiration inversion system, characterized in that, include: The acquisition module is used to acquire the area ratio of non-photovoltaic panel areas, surface temperature, and remote sensing image data of the target photovoltaic area. The first calculation module is used to obtain the photovoltaic panel temperature by the proportion of non-photovoltaic panel area and the surface temperature of the target photovoltaic area, and input the photovoltaic panel temperature into the photovoltaic power generation efficiency model to obtain the photovoltaic power generation efficiency. The correction module is used to construct an SEBS model based on remote sensing image data of the target photovoltaic area. It corrects the instantaneous net radiation in the SEBS model by the proportion of non-photovoltaic panel area and photovoltaic power generation efficiency, corrects the instantaneous soil heat flux in the SEBS model by the corrected instantaneous net radiation of the photovoltaic area and canopy coverage, and corrects the atmospheric sensible heat under dry and wet conditions in the SEBS model by the corrected soil heat flux and instantaneous net radiation of the photovoltaic area. The second calculation module is used to calculate the evaporation ratio based on the corrected instantaneous net radiation of the photovoltaic area, soil heat flux, and atmospheric sensible heat and instantaneous net radiation of the photovoltaic area under dry and wet conditions, and to calculate the daily evapotranspiration through the evaporation ratio.

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