A method and system for synchronous detection of carbon dioxide and semi-heavy water

Abstract

The present application discloses a method and system for synchronous detection of carbon dioxide and semi-heavy water in the field of environmental detection. The method comprises: determining a first online wavelength for differential detection of carbon dioxide and a second online wavelength for differential detection of semi-heavy water and an offline wavelength shared by the two based on the absorption spectrum line obtained from the HITRAN database; calculating an estimated value of the concentration of semi-heavy water in the atmosphere according to meteorological data; determining a semi-heavy water concentration threshold suitable for semi-heavy water detection based on the second online wavelength and the offline wavelength according to a preset semi-heavy water concentration error and meteorological data; judging whether the current atmosphere meets the semi-heavy water detection conditions according to the semi-heavy water concentration threshold and the estimated semi-heavy water concentration; if so, performing synchronous detection of atmospheric carbon dioxide and semi-heavy water according to the first online wavelength, the second online wavelength and the offline wavelength to obtain the carbon dioxide concentration and the semi-heavy water concentration. The present application realizes synchronous detection of carbon dioxide and semi-heavy water based on coherent laser radar.

Description

Technical Field

[0001] The present application belongs to the field of environmental detection, and relates to a method and system for synchronous detection of carbon dioxide and semi-heavy water, and specifically to a method and system for synchronous detection of carbon dioxide and semi-heavy water based on coherent laser radar. Background Art

[0002] Carbon dioxide and water vapor are the main greenhouse gases in the Earth's atmosphere. Water vapor has a relatively short lifetime in the atmosphere through the water cycle process, and its changing characteristics can be obtained by tracking its stable isotopes, such as semi-heavy water. Therefore, accurate detection of carbon dioxide and semi-heavy water is of great significance for a deeper understanding of global warming and climate change.

[0003] Current gas detection methods include contact analyzers and active and passive remote sensing equipment. The detection range of contact analyzers is limited, and passive remote sensing relies on sunlight, which cannot achieve continuous detection day and night. Active remote sensing methods based on lidar can effectively make up for the above shortcomings.

[0004] Differential absorption lidar is the most typical lidar used for gas detection. Conventional differential absorption lidar emits two wavelengths of laser light and detects a specific gas by comparing the absorption difference between the two wavelengths. Differential absorption lidar can be divided into direct detection and coherent detection. Coherent detection can achieve the same detection performance as direct detection at a lower cost and smaller volume, which is more conducive to the miniaturization and integration of the system.

[0005] However, carbon dioxide differential absorption lidar is greatly affected by semi-heavy water in the near-infrared band, and existing lidars have ignored this effect because they cannot achieve simultaneous detection of multiple gases. This limits the detection accuracy of carbon dioxide on the one hand, and limits further understanding of water vapor isotopes on the other. Summary of the invention

[0006] Purpose: In view of at least one of the above technical problems, the present application provides a method and system for synchronous detection of carbon dioxide and semi-heavy water based on coherent lidar, which can realize the detection of multiple gases based on a set of coherent systems and can further improve the detection accuracy of carbon dioxide.

[0007] The technical solution adopted in this application is:

[0008] In a first aspect, the present application provides a method for synchronous detection of carbon dioxide and semi-heavy water, comprising:

[0009] S1. Obtain the spectral parameters of carbon dioxide and semi-heavy water based on the HITRAN database, and select an absorption spectrum line containing both carbon dioxide and semi-heavy water for detection;

[0010] S2. Determine a first online wavelength for differential detection of carbon dioxide based on the absorption spectrum line and a second online wavelength for differential detection of semi-heavy water , and an offline wavelength shared by both ;in - Wavelength pairs are used for differential detection of carbon dioxide; - Wavelength pairs are used for differential detection of semi-heavy water;

[0011] S3. Calculating an estimated value of the concentration of semi-heavy water in the atmosphere according to meteorological data, wherein the meteorological data includes atmospheric temperature, atmospheric pressure and relative humidity;

[0012] S4. Based on the - The wavelength pair determines the semi-heavy water concentration threshold suitable for semi-heavy water detection according to the preset semi-heavy water concentration error and meteorological data;

[0013] S5. judging whether the current atmosphere meets the semi-heavy water detection condition according to the semi-heavy water concentration threshold and the semi-heavy water concentration estimation value;

[0014] S6. If the current atmosphere meets the semi-heavy water detection conditions, - Wavelength pair and - The wavelength pairs are used to synchronously detect atmospheric carbon dioxide and semi-heavy water to obtain the concentrations of carbon dioxide and semi-heavy water.

[0015] In some embodiments, the method further comprises:

[0016] S7. If the current atmosphere does not meet the semi-heavy water detection conditions, use - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data.

[0017] In some embodiments, in step S2, the first online wavelength , Second online wavelength and offline wavelength The following conditions are met:

[0018] and .

[0019] In some embodiments, in step S3, the estimated value of the concentration of semi-heavy water in the atmosphere is calculated based on meteorological data, including:

[0020] The water vapor content value is obtained by converting the relative humidity;

[0021] The water vapor content value is converted into an estimated value of semi-heavy water concentration based on isotope abundance :

[0022] ,

[0023] in, is the estimated concentration of semi-heavy water in the atmosphere, is the water vapor content value, is the relative molecular mass of semi-heavy water, T is the atmospheric temperature, and P is the atmospheric pressure.

[0024] In some embodiments, in step S4, based on the - The wavelength pair determines the semi-heavy water concentration threshold suitable for semi-heavy water detection according to the preset semi-heavy water concentration error and meteorological data, including:

[0025] Calculated according to the preset semi-heavy water concentration error - Wavelength dependence of differential optical depth threshold for lower hemispheric water ;

[0026] ,

[0027] in, is the preset semi-heavy water concentration error, R is the total detection distance, Δr is the discrete range gate on the total detection distance and is defined as the range resolution, is the differential optical depth threshold for the 0-R path integral, for Ratio of the differential optical depth within Δr distance, m 0 The second online wavelength and offline wavelength The total number of pulses emitted by the laser, SNR is the signal-to-noise ratio of the lidar signal;

[0028] Differential optical depth threshold based on semi-heavy water Determining the semi-heavy water concentration threshold ;

[0029] ,

[0030] in is the concentration threshold of semi-heavy water, is the differential optical depth threshold of semi-heavy water, is the Boltzmann constant, T is the atmospheric temperature, R is the total detection distance, The second online wavelength and offline wavelength The differential absorption cross section is , where P is the atmospheric pressure.

[0031] In some embodiments, in step S5, judging whether the current atmosphere meets the semi-heavy water detection condition according to the semi-heavy water concentration threshold and the semi-heavy water concentration estimation value includes:

[0032] If the estimated concentration of semi-heavy water Greater than or equal to the semi-heavy water concentration threshold , judge that the current atmosphere meets the conditions for semi-heavy water detection;

[0033] If the estimated concentration of semi-heavy water Less than the semi-heavy water concentration threshold , judging that the current atmosphere does not meet the conditions for semi-heavy water detection.

[0034] In some embodiments, in step S7, - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data, including:

[0035] According to the estimated concentration of semi-heavy water Obtaining a differential optical depth estimate for semi-heavy water ;

[0036] according to - The first total differential optical depth is calculated from the echo signals of the wavelength pair ;

[0037] The first total differential optical depth Subtracting semi-heavy water differential optical depth estimate Get CO2 Differential Optical Depth ;

[0038] Differential optical depth based on CO2 Get the carbon dioxide concentration .

[0039] In some embodiments, in step S6, according to the - Wavelength pair and - The wavelength pairs are used to synchronously detect atmospheric carbon dioxide and semi-heavy water to obtain the concentration of carbon dioxide and semi-heavy water, including:

[0040] S61, according to the estimated value of the semi-heavy water concentration Obtaining a differential optical depth estimate for semi-heavy water ;according to - The first total differential optical depth is calculated from the echo signals of the wavelength pair ;according to - The second total differential optical depth is calculated by the echo signal of the wavelength pair ;

[0041] S62, the semi-heavy water differential optical depth estimation value As a priori, the first total differential optical depth Subtracting semi-heavy water differential optical depth estimate Get the i-th carbon dioxide concentration , and according to the i-th carbon dioxide concentration Calculate the i-th carbon dioxide differential optical depth ;

[0042] S63, the second total differential optical depth Subtract the ith CO2 differential optical depth Get the i-th semi-heavy water differential optical depth , and according to the i-th half-heavy water differential optical depth Calculate the concentration of semi-heavy water ;

[0043] S64, according to the i-th carbon dioxide concentration obtained in step S62 and the i-th semi-heavy water concentration obtained in step S63 , based on the HITRAN database, the theoretical value of the total differential optical depth under ideal conditions is obtained ;

[0044] S65, if the first total differential optical depth and the total differential optical depth theoretical value The error between them is greater than the preset error, and the i-th semi-heavy water differential optical depth Update the estimated value of the semi-heavy water differential optical depth, and return to steps S62 to S64 for iterative calculation until the first total differential optical depth is and the total differential optical depth theoretical value If the error between them is not greater than the preset error, the iterative calculation is stopped and the corresponding carbon dioxide concentration at this time is and the i-th semi-heavy water concentration as the final carbon dioxide concentration and half-heavy water concentration.

[0045] In some embodiments, after obtaining the carbon dioxide concentration and / or the semi-heavy water concentration, the method further includes:

[0046] Obtain vertical wind speed information using a coherent algorithm based on offline wavelength;

[0047] The carbon dioxide flux is calculated based on the vertical wind speed information and the carbon dioxide concentration, and / or the semi-heavy water flux is calculated based on the vertical wind speed information and the semi-heavy water concentration.

[0048] In some embodiments, the detection device used by the coherent algorithm of the present application is a three-wavelength coherent differential absorption lidar.

[0049] In some embodiments, vertical wind speed information is obtained using a coherent algorithm based on an offline wavelength, including: performing Fourier transform on a beat frequency signal of heterodyne detection of the offline wavelength local oscillator light and the detection light to obtain a power spectrum, and obtaining the vertical wind speed information by analyzing the frequency components of the power spectrum.

[0050] In some embodiments, the carbon dioxide flux is calculated according to the vertical wind speed information and the carbon dioxide concentration, and the carbon dioxide flux is calculated according to the vertical wind speed information and the semi-heavy water concentration, including:

[0051] Fluctuations in carbon dioxide concentration and semi-deuterated water concentration Fluctuation and vertical wind speed fluctuation CO2 flux and semi-heavy water flux :

[0052] ,

[0053] ,

[0054] in Indicates vertical wind speed Fluctuations after distance accumulation and time averaging, is the carbon dioxide concentration Fluctuations after distance accumulation and time averaging, Half heavy water concentration Fluctuations after distance accumulation and time averaging.

[0055] In a second aspect, the present application provides a carbon dioxide and semi-heavy water synchronous detection system, including a processor and a storage medium;

[0056] The storage medium is used to store instructions;

[0057] The processor is configured to operate according to the instructions to execute the method according to the first aspect.

[0058] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method described in the first aspect.

[0059] In a fourth aspect, the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described in the first aspect when executing the computer program.

[0060] In a fifth aspect, the present application provides a computer program product, comprising a computer program, which implements the steps of the method described in the first aspect when executed by a processor.

[0061] Beneficial effects: The method and system for synchronous detection of carbon dioxide, semi-heavy water and their flux provided in this application have the following advantages:

[0062] (1) The present application selects an absorption line containing two gas absorptions for coherent differential absorption detection. By setting three wavelengths (two wavelength pairs), the problem that the absorption line is affected by water vapor and this effect has been ignored for a long time is solved.

[0063] (2) This application adopts the method of alternating three wavelengths and selects different combinations of wavelength pairs for atmospheric detection according to different atmospheric conditions, especially under conditions with low semi-heavy water content, by setting a threshold to only emit - The wavelength pair greatly improves the detection efficiency of the system.

[0064] (3) This application adopts a coherent detection method, which can greatly reduce the complexity of the lidar system compared to direct detection. While realizing the detection of multiple gases, it also reduces the cost and volume, and is also conducive to improving the stability and reliability of the system.

[0065] (4) Compared with the existing technology, the present application uses a single coherent lidar device to achieve the simultaneous detection of carbon dioxide and semi-heavy water, and further improves the detection accuracy of carbon dioxide, providing an effective detection method for carbon emission monitoring and isotope tracking, which is of great significance for the study of greenhouse effect and climate change.

[0066] (5) Compared with the existing technology, the present application can also realize atmospheric wind field detection. By combining the detected carbon dioxide concentration, semi-heavy water concentration and wind speed data, the carbon dioxide flux and water vapor flux can be further analyzed to provide effective data support for the atmospheric carbon and water cycle process. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 Schematic diagram of a flow chart of a method for simultaneous detection of carbon dioxide and semi-heavy water according to an embodiment of the present application;

[0068] Figure 2 This is a schematic diagram of a carbon dioxide and semi-heavy water synchronous detection system according to an embodiment of the present application;

[0069] Figure 3 A schematic diagram of selecting absorption spectrum lines and detection wavelengths under different atmospheric conditions according to an embodiment of the present application;

[0070] Figure 4 Schematic diagram of detection error corresponding to the case where wavelength is not corrected for detecting carbon dioxide according to an embodiment of the present application. DETAILED DESCRIPTION

[0071] The present application is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and cannot be used to limit the protection scope of the present application.

[0072] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0073] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0074] Embodiment 1: This embodiment provides a method for synchronous detection of carbon dioxide and semi-heavy water, such as Figure 1 As shown, including:

[0075] S1. Obtain the spectral parameters of carbon dioxide and semi-heavy water based on the HITRAN database, and select an absorption spectrum line containing both carbon dioxide and semi-heavy water for detection;

[0076] S2. Determine a first online wavelength for differential detection of carbon dioxide based on the absorption spectrum line and a second online wavelength for differential detection of semi-heavy water , and an offline wavelength shared by both ;in - Wavelength pairs are used for differential detection of carbon dioxide; - Wavelength pairs are used for differential detection of semi-heavy water;

[0077] S3. Calculating an estimated value of the concentration of semi-heavy water in the atmosphere according to meteorological data, wherein the meteorological data includes atmospheric temperature, atmospheric pressure and relative humidity;

[0078] S4. Based on the - The wavelength pair determines the semi-heavy water concentration threshold suitable for semi-heavy water detection according to the preset semi-heavy water concentration error and meteorological data;

[0079] S5. judging whether the current atmosphere meets the semi-heavy water detection condition according to the semi-heavy water concentration threshold and the semi-heavy water concentration estimation value;

[0080] S6. If the current atmosphere meets the semi-heavy water detection conditions, - Wavelength pair and - The wavelength pairs are used to synchronously detect atmospheric carbon dioxide and semi-heavy water to obtain the concentrations of carbon dioxide and semi-heavy water.

[0081] In some embodiments, S7, if the current atmosphere does not meet the semi-heavy water detection conditions, use - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data.

[0082] In some embodiments, the first online wavelength , Second online wavelength and offline wavelength The following conditions are met:

[0083] and .

[0084] In some embodiments, in step S3, the estimated value of the concentration of semi-heavy water in the atmosphere is calculated based on meteorological data, including:

[0085] Calculate the water vapor content based on relative humidity ;

[0086] The water vapor content value is converted into an estimated value of semi-heavy water concentration based on isotope abundance :

[0087] ,

[0088] in, is the estimated concentration of semi-heavy water in the atmosphere, is the relative molecular mass of semi-heavy water, T is the atmospheric temperature, and P is the atmospheric pressure.

[0089] In some embodiments, the detection device used by the coherent algorithm of the present application is a three-wavelength coherent differential absorption laser radar. In this embodiment, a synchronous detection device for carbon dioxide and semi-heavy water based on a coherent laser radar is used.

[0090] In some embodiments, Figure 2 As shown, a synchronous detection device for carbon dioxide and semi-heavy water based on coherent laser radar includes: a first online wavelength laser 1, an offline wavelength laser 2, a second online wavelength laser 3, an optical switch 4, a beam splitter 5, an acousto-optic modulator 6, an amplifier 7, a circulator 8, a telescope 9, a mixer 10, a balanced detector 11, an analog-to-digital converter 12 and a computer 13, wherein:

[0091] The output end of the first online wavelength laser 1 is connected to the first input end of the optical switch 4; the output end of the offline wavelength laser 2 is connected to the second input end of the optical switch; the output end of the second online wavelength laser 3 is connected to the third input end of the optical switch 3; the output end of the optical switch 4 is connected to the input end of the beam splitter 5; the first output end of the beam splitter 5 is connected to the input end of the acousto-optic modulator; the second output end of the beam splitter 5 is connected to the first input end of the mixer 10; the output end of the acousto-optic modulator is connected to the input end of the amplifier 7; the output end of the amplifier 7 is connected to the first port of the circulator 8; the second port of the circulator 8 is connected to the input end of the telescope; the backscattered signal of the output end of the telescope connected to the atmosphere for gas detection is connected to the second input end of the mixer 10 through the third port of the circulator 8; the first output end of the mixer 10 is connected to the first input end of the balanced detector 11; the second output end of the mixer 10 is connected to the second input end of the balanced detector 11; the output end of the balanced detector is connected to the input end of the analog-to-digital converter 12; the output end of the analog-to-digital converter 12 is connected to the input end of the calculator 13.

[0092] The time division multiplexing of the optical switch 4 can realize the alternating emission of the first online wavelength laser 1, the offline wavelength laser 2 and the second online wavelength laser 3, so as to adaptively select different wavelength pairs for atmospheric detection under different atmospheric conditions.

[0093] - Wavelength pairs are used for differential detection of carbon dioxide; - Wavelength pairs are used for differential detection of semi-heavy water;

[0094] Strobe - Wavelength pairs for carbon dioxide detection, gating - Wavelength pairs can detect semi-heavy water, gating - - The wavelength pair allows for simultaneous detection of carbon dioxide and semi-heavy water.

[0095] The first output end and the second output end of the beam splitter 5 correspond to the detection light and the local oscillator light respectively, and the two generate a beat frequency signal through the balanced detector 11, which is converted into power spectrum data by Fourier transformation. By analyzing the frequency and power components of the power spectrum respectively, the distribution of vertical wind speed and gas concentration can be obtained at the same time.

[0096] In some embodiments, Figure 3 As shown in the figure, a schematic diagram of the selection of absorption spectrum lines and detection wavelengths under different atmospheric conditions is provided, where:

[0097] In this embodiment, the first online wavelength is selected 1572.335nm, the second online wavelength 1572.258nm, offline wavelength is 1572.210nm, satisfying and .

[0098] Assume that the concentration error of semi-heavy water is set to , calculated based on the preset semi-heavy water concentration error - Wavelength dependence of differential optical depth threshold for lower hemispheric water ; The relationship between the two is:

[0099] ,

[0100] in is the preset semi-heavy water concentration error, R is the total detection distance, Δr is the discrete range gate on the total detection distance and is defined as the range resolution, then is the differential optical depth threshold for the 0-R path integral, for Ratio of the differential optical depth within Δr distance, m 0 The second online wavelength and offline wavelength The total number of pulses emitted by the laser, SNR is the signal-to-noise ratio of the lidar signal;

[0101] Differential optical depth threshold based on semi-heavy water Determining the semi-heavy water concentration threshold ;

[0102] ,

[0103] in is the concentration threshold of semi-heavy water, is the differential optical depth threshold of semi-heavy water, is the Boltzmann constant, T is the atmospheric temperature, R is the total detection distance, The second online wavelength and offline wavelength The differential absorption cross section is , where P is the atmospheric pressure.

[0104] Figure 3 (a) corresponds to the concentration of semi-heavy water in summer. Greater than or equal to the semi-heavy water concentration threshold In the case of - - Wavelength pairs, alternate switching - and - The wavelength pairs are used for simultaneous detection of atmospheric carbon dioxide and semi-heavy water.

[0105] In some embodiments, the - and - The wavelength pairs are used to synchronously detect atmospheric carbon dioxide and semi-heavy water to obtain the concentration of carbon dioxide and semi-heavy water, including:

[0106] S61, according to the estimated value of the semi-heavy water concentration Obtaining a differential optical depth estimate for semi-heavy water ;according to - The first total differential optical depth is calculated from the echo signals of the wavelength pair ;according to - The second total differential optical depth is calculated by the echo signal of the wavelength pair ;

[0107] S62, the semi-heavy water differential optical depth estimation value As a priori, the first total differential optical depth Subtracting semi-heavy water differential optical depth estimate Get the i-th carbon dioxide concentration , and according to the i-th carbon dioxide concentration Calculate the i-th carbon dioxide differential optical depth ;

[0108] S63, the second total differential optical depth Subtract the ith CO2 differential optical depth Get the i-th semi-heavy water differential optical depth , and according to the i-th half-heavy water differential optical depth Calculate the concentration of semi-heavy water ;

[0109] S64, according to the i-th carbon dioxide concentration obtained in step S62 and the i-th semi-heavy water concentration obtained in step S63 , based on the HITRAN database, the theoretical value of the total differential optical depth under ideal conditions is obtained ;

[0110] S65, if the first total differential optical depth and the total differential optical depth theoretical value The error between them is greater than the preset error, and the i-th semi-heavy water differential optical depth Update the estimated value of the semi-heavy water differential optical depth, and return to steps S62 to S64 for iterative calculation until the first total differential optical depth is and the total differential optical depth theoretical value If the error between them is not greater than the preset error, the iterative calculation is stopped and the corresponding carbon dioxide concentration at this time is and the i-th semi-heavy water concentration as the final carbon dioxide concentration and half-heavy water concentration.

[0111] Furthermore, in some embodiments, after obtaining the carbon dioxide concentration and the semi-heavy water concentration, the method further includes:

[0112] The vertical wind speed information is obtained by using a coherent algorithm based on the offline wavelength;

[0113] The carbon dioxide flux is calculated based on the vertical wind speed information and the carbon dioxide concentration, and the carbon dioxide flux is calculated based on the vertical wind speed information and the semi-heavy water concentration.

[0114] In some embodiments, vertical wind speed information is obtained using a coherent algorithm based on an offline wavelength, including: performing Fourier transform on a beat frequency signal of heterodyne detection of the offline wavelength local oscillator light and the detection light to obtain a power spectrum, and obtaining the vertical wind speed information by analyzing the frequency components of the power spectrum.

[0115] In some embodiments, the carbon dioxide flux is calculated according to the vertical wind speed information and the carbon dioxide concentration, and the semi-heavy water flux is calculated according to the vertical wind speed information and the semi-heavy water concentration, including:

[0116] Fluctuations in carbon dioxide concentration and semi-deuterated water concentration Fluctuation and vertical wind speed fluctuation CO2 flux and semi-heavy water flux :

[0117] ,

[0118] ,

[0119] in Indicates vertical wind speed Fluctuations after distance accumulation and time averaging, is the carbon dioxide concentration Fluctuations after distance accumulation and time averaging, Half heavy water concentration Fluctuations after distance accumulation and time averaging.

[0120] Figure 3 (b) corresponds to the situation in winter when the semi-heavy water content is less than the semi-heavy water concentration threshold. Therefore, it can be seen that only the absorption peak of carbon dioxide is more obvious. At this time, the - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data.

[0121] In some embodiments, step S7, using - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data, including:

[0122] According to the estimated concentration of semi-heavy water Obtaining a differential optical depth estimate for semi-heavy water ;

[0123] according to - The first total differential optical depth is calculated from the echo signals of the wavelength pair ; (the first total differential optical depth includes both the carbon dioxide differential optical depth and the semi-heavy water differential optical depth;)

[0124] The first total differential optical depth Subtracting semi-heavy water differential optical depth estimate Get CO2 Differential Optical Depth ;

[0125] Differential optical depth based on CO2 Get the corrected carbon dioxide concentration .

[0126] Further, similarly, in some embodiments, after obtaining the carbon dioxide concentration, the method may further include: calculating the carbon dioxide flux according to the vertical wind speed information and the semi-heavy water concentration, including:

[0127] Fluctuations in carbon dioxide concentration Vertical wind speed fluctuation CO2 flux :

[0128] ,

[0129] In particular, Figure 4 To use - Schematic diagram of the detection error when the wavelength is not corrected for the detection of carbon dioxide. and The errors are all greater than 3%. The accuracy of carbon dioxide concentration after correction with meteorological data can be improved compared with this situation.

[0130] Figure 3 This is a partial embodiment of the present application. For other atmospheric conditions not involved, the system can adaptively select other wavelength pairs that meet the conditions for detection based on the set semi-heavy water concentration error, thereby improving the detection efficiency of the system.

[0131] Embodiment 2: Based on Embodiment 1, this embodiment provides a carbon dioxide and semi-heavy water synchronous detection system, including a processor and a storage medium;

[0132] The storage medium is used to store instructions;

[0133] The processor is used to operate according to the instructions to execute the steps of the method according to embodiment 1.

[0134] Embodiment 3: Based on Embodiment 1, this embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in Embodiment 1 are implemented.

[0135] Embodiment 4: Based on Embodiment 1, this embodiment provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described in Embodiment 1 when executing the computer program.

[0136] Embodiment 5: Based on Embodiment 1, this embodiment provides a computer program product, including a computer program, which implements the steps of the method described in Embodiment 1 when executed by a processor.

[0137] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0138] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0139] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0140] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0141] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for synchronous detection of carbon dioxide and semi-heavy water, characterized in that: include: S1. Obtain the spectral parameters of carbon dioxide and semi-heavy water based on the HITRAN database, and select an absorption spectrum line containing both carbon dioxide and semi-heavy water for detection; S2. Determine a first online wavelength for differential detection of carbon dioxide based on the absorption spectrum line and a second online wavelength for differential detection of semi-heavy water , and an offline wavelength shared by both ;in - Wavelength pairs are used for differential detection of carbon dioxide; - The wavelength pair is used for differential detection of semi-heavy water; S3. Calculate an estimated value of the concentration of semi-heavy water in the atmosphere according to meteorological data, wherein the meteorological data includes atmospheric temperature, atmospheric pressure and relative humidity; wherein the estimated value of the concentration of semi-heavy water in the atmosphere calculated according to the meteorological data includes: The water vapor content value is obtained by converting the relative humidity; the water vapor content value is converted into an estimated value of semi-heavy water concentration according to the isotope abundance : ， in, is the estimated concentration of semi-heavy water in the atmosphere, is the water vapor content value, is the relative molecular mass of semi-heavy water, T is the atmospheric temperature, and P is the atmospheric pressure; S4. Based on the - The wavelength pair determines the semi-heavy water concentration threshold suitable for semi-heavy water detection according to the preset semi-heavy water concentration error and meteorological data, specifically including: Calculated according to the preset semi-heavy water concentration error - Wavelength dependence of differential optical depth threshold for lower hemispheric water ; ， in, is the preset semi-heavy water concentration error, let R be the total detection distance, r is the discrete range gate over the total detection range and is defined as the range resolution, is the differential optical depth threshold for the 0-R path integral, for and The ratio of the differential optical depth within the distance r, m0 is the second online wavelength and offline wavelength The total number of pulses emitted by the laser, SNR is the signal-to-noise ratio of the lidar signal; Differential optical depth threshold based on semi-heavy water Determining the semi-heavy water concentration threshold ; ， in is the concentration threshold of semi-heavy water, is the differential optical depth threshold of semi-heavy water, is the Boltzmann constant, T is the atmospheric temperature, R is the total detection distance, The second online wavelength and offline wavelength The differential absorption cross section, P is the atmospheric pressure; S5. judging whether the current atmosphere meets the semi-heavy water detection condition according to the semi-heavy water concentration threshold and the semi-heavy water concentration estimation value; S6. If the current atmosphere meets the semi-heavy water detection conditions, - Wavelength pair and - The wavelength pairs are used to synchronously detect atmospheric carbon dioxide and semi-heavy water to obtain the concentration of carbon dioxide and semi-heavy water, including: S61, according to the estimated value of the semi-heavy water concentration Obtaining a differential optical depth estimate for semi-heavy water ;according to - The first total differential optical depth is calculated from the echo signals of the wavelength pair ;according to - The second total differential optical depth is calculated by the echo signal of the wavelength pair ; S62, the semi-heavy water differential optical depth estimation value As a priori, the first total differential optical depth Subtracting semi-heavy water differential optical depth estimate Get the i-th carbon dioxide concentration , and according to the i-th carbon dioxide concentration Calculate the i-th carbon dioxide differential optical depth ; S63, the second total differential optical depth Subtract the ith CO2 differential optical depth Get the i-th semi-heavy water differential optical depth , and according to the i-th half-heavy water differential optical depth Calculate the concentration of semi-heavy water ; S64, according to the i-th carbon dioxide concentration obtained in step S62 and the i-th semi-heavy water concentration obtained in step S63 , based on the HITRAN database, the theoretical value of the total differential optical depth under ideal conditions is obtained ; S65, if the first total differential optical depth and the total differential optical depth theoretical value The error between them is greater than the preset error, and the i-th semi-heavy water differential optical depth Update the estimated value of the semi-heavy water differential optical depth, and return to steps S62 to S64 for iterative calculation until the first total differential optical depth is and the total differential optical depth theoretical value If the error between them is not greater than the preset error, the iterative calculation is stopped and the corresponding carbon dioxide concentration at this time is and the i-th semi-heavy water concentration as the final carbon dioxide concentration and half-heavy water concentration.

2. The method according to claim 1, characterized in that: Also includes: S7. If the current atmosphere does not meet the semi-heavy water detection conditions, use - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data.

3. The method according to claim 1, characterized in that In step S2, the first online wavelength , Second online wavelength and offline wavelength The following conditions are met: and .

4. The method according to claim 1, characterized in that In step S5, judging whether the current atmosphere meets the semi-heavy water detection condition according to the semi-heavy water concentration threshold and the semi-heavy water concentration estimation value includes: If the estimated concentration of semi-heavy water Greater than or equal to the semi-heavy water concentration threshold , judge that the current atmosphere meets the conditions for semi-heavy water detection; If the estimated concentration of semi-heavy water Less than the semi-heavy water concentration threshold , judging that the current atmosphere does not meet the conditions for semi-heavy water detection.

5. The method according to claim 2, characterized in that: In step S7, adopt - The wavelength pairs are used to detect atmospheric carbon dioxide and the carbon dioxide concentration is corrected according to the meteorological data, including: According to the estimated concentration of semi-heavy water Obtaining a differential optical depth estimate for semi-heavy water ; according to - The first total differential optical depth is calculated from the echo signals of the wavelength pair ; The first total differential optical depth Subtracting semi-heavy water differential optical depth estimate Get CO2 Differential Optical Depth ; Differential optical depth based on CO2 Get the carbon dioxide concentration .

6. The method according to claim 1, characterized in that After obtaining the concentration of carbon dioxide and semi-heavy water, it also includes: Obtain vertical wind speed information using a coherent algorithm based on offline wavelength; The carbon dioxide flux is calculated according to the vertical wind speed information and the carbon dioxide concentration, and the semi-heavy water flux is calculated according to the vertical wind speed information and the semi-heavy water concentration.

7. A carbon dioxide and semi-heavy water synchronous detection system, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 6.

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