Earth surface incident short wave radiation estimation method and system based on cloud coverage information

Abstract

The invention provides an earth surface incident short wave radiation estimation method and system based on cloud coverage information, and the method comprises the steps: directly simulating a function relation between a TOA radiation parameter and an earth surface radiation parameter under a partial cloud condition through observation data, and converting the DSSR under the all-sky condition into a radiation transfer equation among a TOA observation value, a clear sky radiation parameter and a cloud coverage degree according to the function relationship, thereby estimating a more accurate DSSR. According to the invention, research is carried out by directly utilizing the correlation between the TOA radiation parameter and the earth surface radiation parameter, and cloud coverage information is embedded in the radiation transmission process; the method effectively avoids estimation difficulty caused by insufficient atmospheric parameters and estimation deviation caused by insufficient consideration of the influence of cloud coverage on radiation parameters in a traditional method which needs to take atmosphere or meteorological conditions as intermedia.

Description

Technical Field

[0001] The present invention relates to the technical field of meteorological radiation energy balance, and in particular to a method and system for estimating surface incident shortwave radiation based on cloud coverage information. Background Art

[0002] Downward Surface Shortwave Radiation (DSSR) (spectral range 0.3-3.0μm) is one of the important parameters of the Earth's radiation energy balance, driving the exchange of matter (such as carbon, water, etc.) and energy between the surface and the atmosphere. DSSR is an essential input parameter in general land surface process models and global climate models. Due to the limited observation range of ground stations, estimating the radiation reaching the surface based on satellite remote sensing technology is an effective means to obtain large-scale and long-term DSSR.

[0003] Unlike the radiation parameters at the top of the atmosphere (TOA), the DSSR below the atmosphere cannot be directly observed by satellite. Based on the coupling characteristics of TOA radiation parameters and surface radiation parameters, a variety of DSSR inversion algorithms using satellite data have been developed: the empirical model simplifies the complex attenuation process of solar radiation in atmospheric transmission by establishing a statistical relationship between satellite observations and ground observation data, thereby estimating DSSR; the parameterized model simplifies the radiation transfer calculation process into a parametric equation, and estimates DSSR using cloud and water vapor information from satellite observation data; the radiation transfer model is based on radiation transfer theory, and estimates DSSR by simulating the transmission, scattering and absorption process of solar radiation in the atmosphere and on the surface; the hybrid model combines different principles or methods to obtain more accurate SSR estimation results. These methods all require relatively accurate atmospheric parameter information during the estimation process.

[0004] People usually use a variety of technical means to establish the relationship between TOA radiance and atmospheric condition index, and then establish the relationship between the atmospheric condition index and the surface radiation to achieve indirect inversion of DSSR. However, the clouds that are widely present in the atmosphere interact violently with solar radiation, changing the direction and intensity of the incident shortwave radiation on the surface, thus bringing great uncertainty to the estimation of the incident shortwave radiation on the surface. This uncertainty is largely due to the inaccurate estimation of complex cloud parameters such as cloud optical thickness, height, type, and water vapor content inside the cloud. Among all cloud parameters, cloud cover - that is, the proportion of horizontal area covered by clouds on the earth's surface - has been proven to be one of the key indicators that affect the accuracy of DSSR estimation. However, the existing radiation transfer model can only simulate the radiation transfer characteristics under completely clear sky and completely cloudy conditions, and does not directly consider the influence of cloud cover. In addition, due to the plane parallel assumption of clouds, the existing estimation method can only invert the radiation parameters under two extreme conditions: clear sky (CF=0) and cloudy sky (CF=100%). For all-sky conditions, the cloud cover, an important influencing parameter, is not directly linked to the estimation accuracy of radiation parameters. The indirect estimation method using the established radiation transfer relationship and existing cloud products is prone to cause the transmission and accumulation of errors, thereby reducing the inversion accuracy of radiation parameters. Summary of the invention

[0005] The present invention provides a method and system for estimating incident shortwave radiation from the ground surface based on cloud coverage information, so as to solve the defect in the prior art that the influence of cloud coverage factor is not fully considered when estimating incident shortwave radiation from the ground surface.

[0006] In a first aspect, the present invention provides a method for estimating incident shortwave radiation on the surface of the earth based on cloud coverage information, comprising: Acquire remote sensing observation data, including top of atmosphere observation data and surface observation data; Using the remote sensing observation data to simulate the functional relationship between the top of the atmosphere radiation parameters and the surface radiation parameters under partially cloudy conditions; According to the functional relationship, the incident shortwave radiation of the surface under all-sky conditions is converted into the radiation transfer equation of the top of the atmosphere observation value, clear sky radiation parameters and cloud coverage, and the incident shortwave radiation of the surface under different cloud coverage conditions is estimated by the radiation transfer equation.

[0007] According to a method for estimating incident shortwave radiation from the ground surface based on cloud coverage information provided by the present invention, the top of atmosphere radiation parameters include incident shortwave radiation from the top of the atmosphere and outgoing shortwave radiation under clear sky and full sky conditions; The functional relationship between the top of atmosphere radiation parameter and the surface radiation parameter is obtained by a linear function between the top of atmosphere albedo under full sky conditions, the atmosphere absorptivity under full sky conditions and the surface absorptivity; The albedo of the top of the atmosphere is obtained by the solar radiation reflected by the top of the atmosphere and the total solar radiation incident on the top of the atmosphere under full sky conditions; The atmospheric absorptivity is obtained by the total solar radiation incident on the top of the atmosphere, the solar radiation reflected from the top of the atmosphere under full sky conditions, the downward shortwave radiation from the ground under full sky conditions, and the shortwave radiation reflected from the ground under full sky conditions.

[0008] According to a method for estimating incident shortwave radiation on the surface based on cloud coverage information provided by the present invention, the surface radiation parameters include the sum of the surface downward radiation flux when the surface has no contribution and the multiple reflection effect between the atmosphere and the bright surface, and the surface downward radiation flux when the surface has no contribution and the multiple reflection effect between the atmosphere and the bright surface are both functions of the cosine value of the solar zenith angle; The cloud coverage is determined by weighted summing the surface downward radiation flux under cloudy conditions, the surface downward radiation flux under clear conditions and the cloud coverage when the surface albedo is 0 to obtain the surface downward radiation flux when the surface has no contribution.

[0009] According to a method for estimating surface incident shortwave radiation based on cloud coverage information provided by the present invention, the correlation coefficient between the clear sky surface downward shortwave radiation and the surface downward shortwave radiation under cloudy conditions is obtained by the sum of the cloud albedo and the cloud absorptivity. Considering that the cloud absorptivity is much smaller than the cloud albedo, the correlation coefficient ignores the cloud absorptivity. Based on the correlation coefficient and the surface downward radiation flux under the clear sky conditions, the surface downward radiation flux under cloudy conditions when the surface albedo is 0 is obtained. Correspondingly, based on the surface downward radiation flux under the clear sky condition, the cloud albedo and the cloud coverage, the surface downward radiation flux under full sky conditions when the surface has no contribution is obtained.

[0010] Convert cloud albedo to a function of surface albedo, cloud cover, and effective cloud albedo; The effective cloud albedo is obtained from the surface net shortwave radiation, clear sky shortwave radiation and surface albedo; The net shortwave radiation of the surface is obtained by multiplying the incident shortwave radiation at the top of the atmosphere and the surface absorptivity.

[0011] According to a method for estimating incident shortwave radiation on the ground based on cloud coverage information provided by the present invention, the transmittance of the atmosphere to diffuse radiation under cloud conditions is determined; The multiple reflection effect between the atmosphere and the bright surface is obtained from the surface albedo, the surface downward radiation flux when the surface has no contribution, the cloud albedo, the cloud coverage and the atmosphere transmittance of diffuse radiation under the cloud condition.

[0012] According to a method for estimating surface incident shortwave radiation based on cloud coverage information provided by the present invention, the transmittance of the atmosphere to diffuse radiation under full sky conditions, the transmittance of the atmosphere to diffuse radiation under clear sky conditions and the cloud coverage are used to obtain the transmittance of the atmosphere to diffuse radiation under cloud conditions.

[0013] According to a method for estimating incident shortwave radiation on a ground surface based on cloud coverage information provided by the present invention, the ground surface is a Lambertian surface.

[0014] In a second aspect, the present invention further provides a surface incident shortwave radiation estimation system based on cloud coverage information, comprising: An acquisition module is used to acquire remote sensing observation data, including top of atmosphere observation data and surface observation data; A first estimation module is used to simulate the functional relationship between the top of atmosphere radiation parameter and the surface radiation parameter under partially cloudy conditions using the remote sensing observation data; The second estimation module is used to convert the incident shortwave radiation of the surface under all-sky conditions into the correlation relationship between the top of the atmosphere observation value, the clear sky radiation parameter and the cloud coverage according to the radiation transfer relationship, and estimate the incident shortwave radiation of the surface under different cloud coverage conditions from the correlation relationship.

[0015] The method and system for estimating surface incident shortwave radiation based on cloud coverage information provided by the present invention establish a relationship equation between parameters by analyzing the correlation between TOA shortwave radiation and surface shortwave radiation parameters, and link TOA observations with surface shortwave radiation; derive the relationship between TOA radiation parameters, clear sky radiation parameters, cloud coverage and DSSR based on existing data sets and empirical formulas, without considering atmospheric information; directly embed cloud coverage information into the process of radiation transmission estimation based on the existing relationship, calculate DSSR and perform accuracy verification, effectively reducing the uncertainty of DSSR estimation and improving accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the flow of the method for estimating the surface incident shortwave radiation based on cloud coverage information provided by the present invention; Figure 2 It is a relationship diagram between the albedo of the top of the atmosphere and the absorptivity of the surface provided by the present invention; Figure 3It is a scatter plot comparing the DSSR estimated by the single-layer radiation transfer model provided by the present invention and the CERES-SYN DSSR; Figure 4 It is a scatter plot comparing the estimated DSSR and CERES-EBAF DSSR provided by the present invention with the ground observation values; Figure 5 It is a structural schematic diagram of a surface incident shortwave radiation estimation system based on cloud coverage information provided by the present invention; Figure 6 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In view of the problem in the prior art that atmospheric parameters are insufficient and accurate DSSR under different cloud coverage conditions cannot be directly estimated, the present invention proposes a method for directly estimating surface incident shortwave radiation by embedding cloud coverage information.

[0020] Figure 1 FIG. 1 is a flow chart of a method for estimating incident shortwave radiation on the ground based on cloud coverage information provided by an embodiment of the present invention. Figure 1 As shown, including: Step 100: Acquire remote sensing observation data, including top of atmosphere observation data and surface observation data; Step 200: using the remote sensing observation data to simulate the functional relationship between the top of the atmosphere radiation parameter and the surface radiation parameter under partially cloudy conditions; Step 300: According to the functional relationship, the incident shortwave radiation of the surface under all-sky conditions is converted into a radiation transfer equation of top-of-atmosphere observations, clear-sky radiation parameters and cloud coverage, and the incident shortwave radiation of the surface under different cloud coverage conditions is estimated by the radiation transfer equation.

[0021] The embodiment of the present invention uses observation data to directly simulate the functional relationship between TOA radiation parameters and surface radiation parameters under partially cloudy conditions, and converts the DSSR under full-sky conditions into a radiation transfer equation between TOA observations, clear sky radiation parameters and cloud coverage, thereby estimating a more accurate DSSR.

[0022] Specifically, in remote sensing observations, satellites can directly observe the radiation flux at the top of the atmosphere, but the downlink shortwave radiation flux at the surface can only be obtained through inversion. In previous studies, in order to obtain the radiation parameters of the surface, the top of the atmosphere parameters are usually used to provide constraints for the inversion of surface parameters.

[0023] For shortwave radiation flux, the top-of-atmosphere albedo α A and atmospheric absorption rate a It can be defined as: (1) (2) Due to the conservation of energy, (3) in, represents the solar radiation reflected from the top of the atmosphere under full sky conditions, represents the total solar radiation incident on the top of the atmosphere, represents the downward shortwave radiation from the surface under all-sky conditions, Represents the shortwave radiation reflected from the Earth's surface under all-sky conditions.

[0024] The above will a s It is defined as the surface absorptivity, which is the ratio of the energy absorbed by the surface to the total incident energy at the top of the atmosphere. In this formula, α A Can be seen as a s Assuming that the surface albedo does not change significantly with the seasons in a 1°×1° grid, the albedo at the top of the atmosphere is α A and surface absorption rate a s There is a good linear relationship, and the slope of this linear relationship is consistent with the atmospheric absorption rate. a Relative to surface absorption rate a s is related to changes in.

[0025] In the embodiment of the present invention, the ratio of TOA outgoing shortwave radiation to TOA incoming shortwave radiation in the CERES-SYN1deg 1°×1° monthly average grid data in the Arctic region is calculated (i.e. ) and the ratio of the net shortwave radiation at the surface to the incident shortwave radiation at TOA (i.e. a s ) and found that in the Arctic region, and a sHas a good linear relationship, R 2 The linear relationship shows that TOA shortwave radiation can provide a good restriction condition for surface shortwave radiation. If the TOA shortwave radiation parameters and the surface and cloud characteristics are known, the surface downward shortwave radiation of a certain area can be obtained. For clear sky conditions, R 2 can be increased to about 0.984, and the deviation is reduced to about 0.04; for cloudy conditions, R 2 It is slightly lower than that under sunny conditions, while the deviation increases to about 0.22. Figure 2 This is mainly because the error in cloud parameters brings great uncertainty to the estimation of surface radiation parameters. To this end, this study proposes a method to estimate DSSR using TOA observations and clear sky radiation flux, and embeds cloud cover information in the radiation transfer calculation process, so as to separate the sensitivity of cloud cover to surface shortwave radiation from many cloud parameters.

[0026] Therefore, the present invention proposes a method to estimate DSSR using TOA observations and clear sky radiation flux, and embeds cloud cover information in the radiation transfer calculation process, so as to separate the sensitivity of cloud cover to surface shortwave radiation from many cloud parameters.

[0027] Assuming that the surface is a Lambertian surface, the downward radiation flux from the surface is calculated as: (4) The first term of the formula represents the downward radiation flux from the surface when there is no contribution from the surface, and the second term represents the multiple reflection effect between the atmosphere and the bright surface. is the cosine of the solar zenith angle. When considering the influence of cloud coverage, By cloud cover f Weighted to get: (5) in, It represents the downward radiation flux of the surface under cloudy conditions when the surface albedo is 0. represents the downward radiation flux of the surface under clear sky conditions. According to the research of Liu et al. and Xie et al., It can be expressed as Function: (6) (7) in, is the cloud albedo, is the cloud absorptivity, and the subscript 0 indicates that the surface albedo is 0. Usually, the cloud absorptivity is much smaller than the cloud albedo, and in the present invention, it can be ignored. It is expressed as: (8) In general, cloud albedo maintains a close relationship between cloud cover and planetary albedo (or shortwave (SW) radiation reflected by the top of the atmosphere (TOA)), which has been confirmed in various observational records. In order to further calculate cloud albedo, the present invention introduces the concept of effective cloud albedo.

[0028] (9) in, represents the effective cloud albedo, which has a similar mathematical expression to the surface albedo, but is a dimensionless value. Liu et al. showed through their research that when considering the multiple reflection effect between clouds and the surface, It can be approximately expressed as the product of cloud albedo, surface albedo and cloud cover. (10) for r s =0 condition, r s Represents the surface albedo (11) In order to calculate the effective cloud albedo smoothly, multiply the numerator and denominator of formula (9) by the function of the surface albedo at the same time, and we get: (12) therefore: (13) in is the net shortwave radiation from the surface. According to the previous analysis, the surface absorption rate a s It can also be expressed as a function of the net shortwave radiation from the surface. Therefore, the effective albedo of the cloud can be expressed as a function of the TOA incident SW and the surface absorptivity, (14) Considering It can be expressed as a linear function of TOA albedo, and the corresponding cloud albedo can be calculated using TOA observations, clear sky surface SW, and cloud cover.

[0029] For Lambertian surfaces, the effect of cloud parameters on diffuse radiation is more obvious under cloudy conditions. Therefore, when considering the multiple reflection effect, the surface reflectivity is r s The surface of (15) Here represents the albedo of the cloud; in, It represents the transmittance of the atmosphere to diffuse radiation under cloud conditions, which depends on a variety of atmospheric factors, such as aerosol, ozone, water vapor, etc. In the present invention, in order to simplify the calculation, empirical parameters are directly used in combination with observed values ​​for estimation.

[0030] (16) represents the transmittance of the atmosphere to diffuse radiation under full sky conditions, represents the transmittance of the atmosphere to diffuse radiation under clear sky conditions, represents the diffuse radiation under full-sky conditions, Represents diffuse radiation under clear-sky conditions.

[0031] Finally, the DSSR under all-sky conditions can be expressed as a function of the TOA shortwave radiation observed by the satellite, the clear sky DSSR and the cloud coverage. In this paper, only the radiative forcing effect related to the cloud coverage perturbation is considered. Therefore, based on the partial perturbation idea, the cloud coverage is used as the only variable that needs to be determined by the user in equation (14), and the other unknown parameters are all from the CERES-SYN1deg data.

[0032] like Figure 3 As shown, it is a scatter plot comparing the DSSR estimated by the present invention using the single-layer radiation transfer model and the CERES-SYN DSSR. Figure 4 Scatter plot comparing the DSSR estimated by the present invention and the CERES-EBAF DSSR with ground observations.

[0033] The method adopted by the present invention directly uses the correlation between TOA radiation parameters and surface radiation parameters to carry out research, effectively avoiding the estimation difficulties caused by insufficient atmospheric parameters in the traditional method that requires the atmosphere or meteorological conditions as an intermediate medium. In addition, this method embeds cloud coverage information into the process of radiation transmission estimation, so that TOA radiation parameters, clear sky radiation parameters and cloud coverage are directly linked to DSSR, avoiding the error transmission and accumulation caused by the traditional method using the established clear sky model and existing cloud coverage products for empirical estimation, effectively reducing the uncertainty of DSSR estimation and improving the accuracy.

[0034] The following describes the surface incident shortwave radiation estimation system based on cloud coverage information provided by the present invention. The surface incident shortwave radiation estimation system based on cloud coverage information described below and the surface incident shortwave radiation estimation method based on cloud coverage information described above can be referenced to each other.

[0035] Figure 5 is a schematic diagram of the structure of a surface incident shortwave radiation estimation system based on cloud coverage information provided by an embodiment of the present invention. Figure 5 As shown, it includes: an acquisition module 51, a first estimation module 52 and a second estimation module 53, wherein: The acquisition module 51 is used to acquire remote sensing observation data, including top of atmosphere observation data and surface observation data; the first estimation module 52 is used to use the remote sensing observation data to simulate the functional relationship between the top of atmosphere radiation parameters and the surface radiation parameters under partially cloudy conditions; the second estimation module 53 is used to convert the surface incident shortwave radiation under full sky conditions into a radiation transfer equation of top of atmosphere observation values, clear sky radiation parameters and cloud coverage according to the functional relationship, and estimate the surface incident shortwave radiation under different cloud coverage conditions by the radiation transfer equation.

[0036] Figure 6 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630 and a communication bus 640, wherein the processor 610, the communication interface 620 and the memory 630 communicate with each other through the communication bus 640. The processor 610 may call the logic instructions in the memory 630 to execute a method for estimating the incident shortwave radiation of the surface based on the cloud coverage information, the method comprising: obtaining remote sensing observation data, including top of atmosphere observation data and surface observation data; using the remote sensing observation data to simulate the functional relationship between the top of atmosphere radiation parameters and the surface radiation parameters under partial cloud conditions; according to the functional relationship, converting the incident shortwave radiation of the surface under full sky conditions into the radiation transfer equation of the top of atmosphere observation value, clear sky radiation parameters and cloud coverage, and estimating the incident shortwave radiation of the surface under different cloud coverage conditions by the radiation transfer equation.

[0037] In addition, the logic instructions in the above-mentioned memory 630 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0038] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the surface incident shortwave radiation estimation method based on cloud coverage information provided by the above-mentioned methods, the method including: obtaining remote sensing observation data, including top of atmosphere observation data and surface observation data; using the remote sensing observation data to simulate the functional relationship between the top of the atmosphere radiation parameters and the surface radiation parameters under partial cloud conditions; according to the functional relationship, converting the surface incident shortwave radiation under full sky conditions into a radiation transfer equation of top of the atmosphere observation values, clear sky radiation parameters and cloud coverage, and estimating the surface incident shortwave radiation under different cloud coverage conditions by the radiation transfer equation.

[0039] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the surface incident shortwave radiation estimation method based on cloud coverage information provided by the above-mentioned methods, the method comprising: acquiring remote sensing observation data, including top of atmosphere observation data and surface observation data; using the remote sensing observation data to simulate the functional relationship between top of atmosphere radiation parameters and surface radiation parameters under partially cloudy conditions; according to the functional relationship, converting the surface incident shortwave radiation under full sky conditions into a radiation transfer equation of top of atmosphere observation values, clear sky radiation parameters and cloud coverage, and estimating the surface incident shortwave radiation under different cloud coverage conditions by the radiation transfer equation.

[0040] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0041] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for estimating surface incident shortwave radiation based on cloud coverage information, characterized in that: include: Acquire remote sensing observation data, including top of atmosphere observation data and surface observation data; Using the remote sensing observation data to simulate the functional relationship between the top of the atmosphere radiation parameters and the surface radiation parameters under partially cloudy conditions; According to the functional relationship, the incident shortwave radiation of the surface under all-sky conditions is converted into the radiation transfer equation of the top of the atmosphere observation value, clear sky radiation parameters and cloud coverage, and the incident shortwave radiation of the surface under different cloud coverage conditions is estimated by the radiation transfer equation.

2. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 1, characterized in that: The top of atmosphere radiation parameters include incident shortwave radiation at the top of the atmosphere and outgoing shortwave radiation under clear sky and full sky conditions.

3. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 1, characterized in that: The functional relationship is obtained from the albedo of the top of the atmosphere under full sky conditions, the atmospheric absorptivity under full sky conditions and the surface absorptivity; The albedo of the top of the atmosphere is obtained by the solar radiation reflected by the top of the atmosphere and the total solar radiation incident on the top of the atmosphere under full sky conditions; The atmospheric absorptivity is obtained by the total solar radiation incident on the top of the atmosphere, the solar radiation reflected from the top of the atmosphere under full sky conditions, the downward shortwave radiation from the ground under full sky conditions, and the shortwave radiation reflected from the ground under full sky conditions.

4. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 1, characterized in that: The surface radiation parameters include the sum of the surface downward radiation flux when the surface has no contribution and the multiple reflection effect between the atmosphere and the bright surface, and the surface downward radiation flux when the surface has no contribution and the multiple reflection effect between the atmosphere and the bright surface are both functions of the cosine value of the solar zenith angle; The cloud coverage is determined by weighted summing the surface downward radiation flux under cloudy conditions, the surface downward radiation flux under clear conditions and the cloud coverage when the surface albedo is 0 to obtain the surface downward radiation flux when the surface has no contribution.

5. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 4, characterized in that: The correlation coefficient between the downward shortwave radiation of the surface in the clear sky and the downward shortwave radiation of the surface under the cloudy sky condition is obtained from the sum of the cloud albedo and the cloud absorptivity. Considering that the cloud absorptivity is much smaller than the cloud albedo, the cloud absorptivity is ignored in the correlation coefficient. The downward radiation flux of the surface under the cloudy sky condition when the surface albedo is 0 is obtained based on the correlation coefficient and the downward radiation flux of the surface under the clear sky condition. Correspondingly, based on the surface downward radiation flux under the clear sky condition, the cloud albedo and the cloud coverage, the surface downward radiation flux under full sky conditions when the surface has no contribution is obtained.

6. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 4, characterized in that: Convert cloud albedo to a function of surface albedo, cloud cover, and effective cloud albedo; The effective cloud albedo is obtained from the surface net shortwave radiation, clear sky shortwave radiation and surface albedo; The net shortwave radiation of the surface is obtained by multiplying the incident shortwave radiation at the top of the atmosphere and the surface absorptivity.

7. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 6, characterized in that: Determine the atmospheric transmittance to diffuse radiation under cloudy conditions; The multiple reflection effect between the atmosphere and the bright surface is obtained from the surface albedo, the surface downward radiation flux when the surface has no contribution, the cloud albedo, the cloud coverage and the atmosphere transmittance of diffuse radiation under the cloud condition.

8. The method for estimating surface incident shortwave radiation based on cloud coverage information according to claim 7, characterized in that: The transmittance of the atmosphere to diffuse radiation under the cloud condition is obtained from the transmittance of the atmosphere to diffuse radiation under the full sky condition, the transmittance of the atmosphere to diffuse radiation under the clear sky condition and the cloud coverage.

9. The method for estimating surface incident shortwave radiation based on cloud coverage information according to any one of claims 1 to 8, characterized in that: The surface is Lambertian.

10. A surface incident shortwave radiation estimation system based on cloud coverage information, characterized in that: include: An acquisition module is used to acquire remote sensing observation data, including top of atmosphere observation data and surface observation data; A first estimation module is used to simulate the functional relationship between the top of atmosphere radiation parameter and the surface radiation parameter under partially cloudy conditions using the remote sensing observation data; The second estimation module is used to convert the surface incident shortwave radiation under full sky conditions into the radiation transfer equation of top of atmosphere observations, clear sky radiation parameters and cloud coverage according to the functional relationship, and estimate the surface incident shortwave radiation under different cloud coverage conditions from the radiation transfer equation relationship.

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