A method, device, equipment and medium for measuring carbon dioxide concentration

Abstract

The present application discloses a method, device, equipment and medium for measuring carbon dioxide concentration, and relates to the field of laser radar telemetry technology. The method comprises: obtaining a vertical profile of temperature and a vertical profile of water vapor mixing ratio in the atmosphere of a target area, and determining a vertical profile of pressure; determining the target air molecule density, target carbon dioxide absorption cross section difference and target water vapor absorption cross section difference at each height in real time based on the vertical profile of temperature and the vertical profile of pressure, and calculating the vertical profile of water vapor molecule density; emitting an original online wavelength and an original offline wavelength, and obtaining a target online echo signal and a target offline echo signal at each height; calculating a target carbon dioxide concentration according to the vertical profile of water vapor molecule density, the target online echo signal, the target offline echo signal, and the target air molecule density, the target carbon dioxide absorption cross section difference and the target water vapor absorption cross section difference at each height to obtain a vertical profile of carbon dioxide concentration. The accuracy of carbon dioxide concentration measurement is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser radar telemetry technology, and in particular to a method, device, equipment and medium for measuring carbon dioxide concentration. Background Art

[0002] At present, in order to meet the needs of three-dimensional monitoring of greenhouse gases in urban environments, it is urgent to develop a carbon dioxide measurement lidar system. Since the 1970s, research on carbon dioxide differential absorption lidar has been carried out at home and abroad to obtain the column concentration or distance-resolved concentration of carbon dioxide near the ground. However, in the process of carbon dioxide concentration inversion, the parameters such as CO2 absorption cross section, air molecule number density, and water vapor molecule density are closely related to atmospheric temperature and pressure. The accuracy of the above parameters directly affects the accuracy of CO2 (carbon dioxide) inversion concentration.

[0003] The existing method of measuring carbon dioxide concentration is to use temperature, pressure, air density and other data from the US standard atmospheric model to calculate the CO2 absorption cross-section difference. However, the temperature, pressure values ​​and air density distribution with altitude at different locations and times vary greatly, resulting in low accuracy.

[0004] In summary, how to improve the accuracy of carbon dioxide concentration measurement is an urgent problem to be solved. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method, device, equipment and medium for measuring carbon dioxide concentration, which can improve the accuracy of carbon dioxide concentration measurement. The specific scheme is as follows:

[0006] In a first aspect, the present application discloses a method for measuring carbon dioxide concentration, comprising:

[0007] Based on the Raman scattering principle, the vertical profile of temperature and the vertical profile of water vapor mixing ratio in the atmosphere of the target area are obtained in real time, and the vertical profile of pressure in the atmosphere of the target area is determined;

[0008] Determine in real time the target air molecule density, target carbon dioxide absorption cross section difference, and target water vapor absorption cross section difference at each height in the atmosphere of the target area based on the temperature vertical profile and the pressure vertical profile, and calculate the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile;

[0009] transmitting the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide;

[0010] The target carbon dioxide concentration at the corresponding height is calculated according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

[0011] Optionally, the real-time acquisition of the vertical profile of the temperature and the vertical profile of the water vapor molecule density in the atmosphere of the target area based on the Raman scattering principle includes:

[0012] A target high-energy pulse obtained after beam expansion of the original high-energy pulse is vertically emitted into the atmosphere of the target area, and a Raman backscattering signal generated based on the target high-energy pulse is acquired. The Raman backscattering signal is then analyzed to obtain a vertical temperature profile and a vertical water vapor mixing ratio profile in the atmosphere in real time.

[0013] Optionally, analyzing the Raman backscattering signal to obtain a vertical profile of temperature and a vertical profile of water vapor molecule density in the atmosphere in real time includes:

[0014] The Raman backscattering signal is subjected to spectroscopic processing to obtain target Raman signals corresponding to different preset wavelengths, and the target Raman signal is analyzed to obtain a vertical profile of temperature and a vertical profile of water vapor mixing ratio in the atmosphere.

[0015] Optionally, the transmitting in real time an original online wavelength and an original offline wavelength into the atmosphere of the target area to obtain a target online echo signal and a target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide, comprises:

[0016] The original online wavelength and the original offline wavelength are vertically emitted in real time into the atmosphere of the target area to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide.

[0017] Optionally, the transmitting in real time an original online wavelength and an original offline wavelength into the atmosphere of the target area to obtain a target online echo signal and a target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide, comprises:

[0018] Transmitting multiple groups of original online wavelengths and original offline wavelengths vertically into the atmosphere of the target area in real time, and acquiring original online echo signals and original offline echo signals at each height corresponding to each group of the original online wavelengths and the original offline wavelengths;

[0019] An average value of the original online echo signal and an average value of the original offline echo signal at each height are calculated to obtain a target online echo signal and a target original offline echo signal.

[0020] Optionally, the calculating the vertical profile of water vapor molecule density based on the vertical profile of water vapor mixing ratio includes:

[0021] Calculating a water vapor volume mixing ratio vertical profile based on the water vapor mixing ratio vertical profile;

[0022] The target water vapor molecule density at each altitude is calculated based on the water vapor volume mixing ratio vertical profile and the target air molecule density at each altitude to obtain a water vapor molecule density vertical profile.

[0023] Optionally, determining a vertical pressure profile in the atmosphere of the target area includes:

[0024] The target pressure at the location of the air pressure sensor is measured by the air pressure sensor, and the pressure at each height in the atmosphere of the target area is calculated based on the target pressure and a target standard atmosphere model to determine the vertical pressure profile in the atmosphere of the target area.

[0025] In a second aspect, the present application discloses a device for measuring carbon dioxide concentration, comprising:

[0026] A vertical profile acquisition module, used to acquire the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, and determine the pressure vertical profile in the atmosphere of the target area;

[0027] an information determination module, for determining a target air molecule density, a target carbon dioxide absorption cross-section difference, and a target water vapor absorption cross-section difference at each height in the atmosphere based on the temperature vertical profile and the pressure vertical profile, and calculating a water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile;

[0028] A signal acquisition module, used for transmitting the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide;

[0029] The carbon dioxide concentration calculation module is used to calculate the target carbon dioxide concentration at the corresponding height according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference, so as to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

[0030] In a third aspect, the present application discloses an electronic device, comprising a processor and a memory; wherein, when the processor executes a computer program stored in the memory, the aforementioned disclosed method for measuring carbon dioxide concentration is implemented.

[0031] In a fourth aspect, the present application discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the aforementioned disclosed method for measuring carbon dioxide concentration is implemented.

[0032] It can be seen that the present application obtains the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, and determines the pressure vertical profile in the atmosphere of the target area; determines the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height in the atmosphere of the target area in real time based on the temperature vertical profile and the pressure vertical profile, and calculates the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile; emits the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide; calculates the target carbon dioxide concentration at the corresponding height according to the water vapor molecule density vertical profile, the target online echo signal, the target offline echo signal and the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height to obtain the carbon dioxide concentration vertical profile in the atmosphere of the target area. It can be seen that the present application obtains the temperature vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, calculates the target carbon dioxide absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and proposes to calculate the target water vapor absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and finally calculates the carbon dioxide concentration vertical profile based on the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference calculated in real time. Because the temperature vertical profile and the pressure vertical profile in the atmosphere are obtained in real time, the accuracy of the carbon dioxide concentration measurement is improved; in addition, the target water vapor absorption cross-section difference is calculated to eliminate the influence of the water vapor absorption cross-section difference on the carbon dioxide concentration calculation, thereby further improving the accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in 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 only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0034] Figure 1 A flow chart of a method for measuring carbon dioxide concentration provided in this application;

[0035] Figure 2 A schematic diagram of the absorption cross section of carbon dioxide and water vapor provided in this application;

[0036] Figure 3 A specific flow chart of a method for measuring carbon dioxide concentration provided in this application;

[0037] Figure 4 A schematic diagram of a carbon dioxide concentration measurement system provided for this application;

[0038] Figure 5 A schematic diagram of a carbon dioxide concentration measurement process provided for this application;

[0039] Figure 6 A schematic diagram of the structure of a carbon dioxide concentration measuring device provided in this application;

[0040] Figure 7 A structural diagram of an electronic device provided for this application. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0042] Currently, the method for measuring carbon dioxide concentration uses temperature, pressure, air density and other data from the US standard atmospheric model to calculate the CO2 absorption cross-section difference. However, the temperature, pressure values ​​and air density distribution with altitude at different locations and times vary greatly, resulting in low accuracy.

[0043] In order to overcome the above problems, the present application provides a carbon dioxide concentration measurement solution, which can improve the accuracy of carbon dioxide concentration measurement.

[0044] See also Figure 1 As shown, the embodiment of the present application discloses a method for measuring carbon dioxide concentration, the method comprising:

[0045] Step S11: based on the Raman scattering principle, the vertical profile of the temperature and the vertical profile of the water vapor mixing ratio in the atmosphere of the target area are acquired in real time, and the vertical profile of the pressure in the atmosphere of the target area is determined.

[0046] In the embodiment of the present application, the specific process of determining the vertical pressure profile of the atmosphere in the target area in real time is: measuring the target pressure at the location of the pressure sensor by the pressure sensor, and calculating the pressure at each height in the atmosphere of the target area based on the target pressure and the target standard atmosphere model to determine the vertical pressure profile of the atmosphere in the target area. Specifically, according to the 1976 American Standard Atmosphere Model, the altitude is obtained. The pressure lookup table at , according to the pressure measured by the air pressure sensor , combined with the altitude of the system, recorded as , then the pressure at a height z above the ground is ;

[0047] In an embodiment of the present application, the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area are acquired in real time based on the Raman scattering principle, so as to calculate the carbon dioxide concentration using the temperature vertical profile and the water vapor mixing ratio vertical profile.

[0048] Step S12: determining in real time the target air molecule density, target carbon dioxide absorption cross-section difference and target water vapor absorption cross-section difference at each height in the atmosphere of the target area based on the temperature vertical profile and the pressure vertical profile, and calculating the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile.

[0049] In the embodiment of the present application, the data fusion module in the carbon dioxide concentration measurement system determines the target air molecule density, target carbon dioxide absorption cross-section difference and target water vapor absorption cross-section difference at each height in the atmosphere of the target area in real time based on the temperature vertical profile and the pressure vertical profile, and calculates the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile. Specifically, based on the temperature vertical profile and the pressure vertical profile, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height in the atmosphere of the target area are determined in real time according to a preset formula. In addition, the water vapor volume mixing ratio vertical profile is calculated based on the water vapor mixing ratio vertical profile; the target water vapor molecule density at each height is calculated based on the water vapor volume mixing ratio vertical profile and the target air molecule density at each height to obtain the water vapor molecule density vertical profile; for example, when calculating the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at height z, the temperature T and pressure P at height z are first determined, and then calculated according to the preset formula. The preset formula is:

[0050] ;

[0051] ;

[0052] ;

[0053] ;

[0054] in, For line strength, , is the integration variable, is the half-width at half-height of the Lorentz spectrum, is the Doppler half-width, is the wave number at the center of the spectrum, and As a function of temperature, is a function of temperature and pressure, T and P are the atmospheric temperature and pressure at height z, respectively. , , for and The reference half-width in the state, for and The line strength in the state, is the transition low energy state, is the molecular constant index at 296K, and can be obtained from the HITRAN database, h is the Planck constant, k B is the Boltzmann constant, c is the speed of light, and m is the molecular mass of the gas.

[0055] It should be pointed out that the target carbon dioxide absorption cross section difference and the target water vapor molecule absorption cross section difference are calculated by the above preset formula, but when calculating the target carbon dioxide absorption cross section difference and the target water vapor molecule absorption cross section difference, , , and are different.

[0056] It should be noted that, for example, to calculate the target air molecule density at height z, specifically, the target air molecule density at height z is calculated based on the temperature T and pressure P at height z. ; The calculation formula is as follows:

[0057] ;

[0058] in, It is the number density of air molecules at a temperature of 296K and a pressure of 1.013×105, also known as the Loschmidt number.

[0059] Let A(z) be the water vapor mixing ratio (g / kg), then the water vapor volume mixing ratio is

[0060] ;

[0061] The density of water vapor molecules is:

[0062] ;

[0063] in, is the mass of air molecules, is the molecular mass of water vapor. is the density of air molecules at height z.

[0064] Step S13: emitting the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide.

[0065] In the embodiment of the present application, the dual-wavelength laser emitting unit in the carbon dioxide differential absorption laser radar module in the carbon dioxide concentration measurement system uses a carbon dioxide transceiver telescope to use differential absorption technology or coherent differential absorption technology to alternately emit the original online wavelength and the original offline wavelength in the atmosphere of the target area in real time at high frequency. It should be noted that the present application adopts a 1572nm or 2um spectrum. It should be noted that differential absorption DIAL (differential absorption laser radar, differential absorption laser radar technology) is to select two different laser wavelengths (usually referred to as online and offline wavelengths) so that one wavelength is absorbed by the gas molecules of interest, while the other wavelength is relatively weakly absorbed. By measuring the subsequent intensity difference of the two returning laser signals, the concentration of the studied molecule can be determined. The principle of differential absorption technology is to select two different laser wavelengths (usually referred to as on wavelength and off wavelength), the on wavelength is selected at the peak of the CO2 absorption peak, and the off wavelength is selected at the valley of the same absorption peak. The concentration information of CO2 is obtained by analyzing the difference in the intensity of the two wavelengths in the laser backscattering signal. It should be noted that the on wavelength is the online wavelength and the off wavelength is the offline wavelength. In addition, the coherent heterodyne technology has the advantages of high measurement sensitivity and no influence from background light. The combination of coherent and differential absorption technology can not only synchronously obtain the wind field profile, but also improve the signal-to-noise ratio of the differential absorption system and reduce the influence of background light.

[0066] In an embodiment of the present application, the dual-wavelength laser emitting unit in the carbon dioxide differential absorption lidar module in the carbon dioxide concentration measurement system transmits the original online wavelength and the original offline wavelength in real time into the atmosphere of the target area through the carbon dioxide transceiver telescope, so as to obtain the target online echo signals and target offline echo signals at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide through the carbon dioxide transceiver telescope in the carbon dioxide differential absorption lidar module in the carbon dioxide concentration measurement system, which are divided into two situations.

[0067] In a specific embodiment, the original online wavelength and the original offline wavelength are vertically emitted into the atmosphere of the target area in real time to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide.

[0068] In another specific embodiment, multiple groups of original online wavelengths and original offline wavelengths are vertically emitted into the atmosphere of the target area in real time, and original online echo signals and original offline echo signals at each height corresponding to each group of the original online wavelengths and the original offline wavelengths are obtained; the average value of the original online echo signals and the average value of the original offline echo signals at each height are calculated to obtain the target online echo signal and the target original offline echo signal.

[0069] It should be pointed out that, according to each group of the original online wavelength and the original offline wavelength, the original online echo signal and the original offline echo signal at each height will be obtained, and the average values ​​of the original online echo signals and the original offline echo signals at each height of each group at the same height are calculated to obtain the target online echo signals and the target offline echo signals at each height in the atmosphere.

[0070] Step S14: Calculate the target carbon dioxide concentration at the corresponding height according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference, so as to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

[0071] In the embodiment of the present application, the carbon dioxide concentration measurement system calculates the target carbon dioxide concentration at the corresponding height according to the target formula based on the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference through a data fusion unit to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area. It should be noted that the target formula is as follows:

[0072] ;

[0073] in, is the distance resolution (distance difference) is the number density of air molecules at height z, is the difference in absorption cross section of CO2 gas at ON wavelength and OFF wavelength, and are the two wavelength energies received by the previous range gate, and Receive two wavelengths of energy for the next range gate respectively, is the density of water molecules at height z, is the difference in the absorption cross section of water vapor at the on wavelength and the off wavelength.

[0074] It should be pointed out that in the present application, it is necessary to use the target offline echo signal and the target online echo signal of the first preset height, as well as the target offline echo signal and the target online echo signal of the second preset height to calculate the carbon dioxide concentration at the target height; wherein the first preset height is the height of the target height vertically a preset distance downward; the second preset height is the height of the target height vertically a preset distance upward.

[0075] It should be noted that when the target water vapor absorption cross section difference is not calculated, the water vapor absorption cross section difference will be used as part of the carbon dioxide absorption cross section difference, resulting in a decrease in the accuracy of the carbon dioxide inverse concentration measurement. Specifically, Figure 2 As shown, it is the absorption cross-section diagram of carbon dioxide and water vapor. At the on wavelength and off wavelength, both will cause absorption intensity, that is, ; n is the number of corresponding gas molecules, σ is the difference between the corresponding gas absorption cross section at two wavelengths. If water vapor interference is not considered and it is miscalculated as CO2 absorption, the error in the number of CO2 molecules will be , and the error caused by concentration is , which is the subtracted second half of the target formula .

[0076] It can be seen that the present application obtains the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, and determines the pressure vertical profile in the atmosphere of the target area; determines the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height in the atmosphere of the target area in real time based on the temperature vertical profile and the pressure vertical profile, and calculates the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile; emits the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide; calculates the target carbon dioxide concentration at the corresponding height according to the water vapor molecule density vertical profile, the target online echo signal, the target offline echo signal and the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height to obtain the carbon dioxide concentration vertical profile in the atmosphere of the target area. It can be seen that the present application obtains the temperature vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, calculates the target carbon dioxide absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and proposes to calculate the target water vapor absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and finally calculates the carbon dioxide concentration vertical profile based on the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference calculated in real time. Because the temperature vertical profile and the pressure vertical profile in the atmosphere are obtained in real time, the accuracy of the carbon dioxide concentration measurement is improved; in addition, the target water vapor absorption cross-section difference is calculated to eliminate the influence of the water vapor absorption cross-section difference on the carbon dioxide concentration calculation, thereby further improving the accuracy.

[0077] See also Figure 3 As shown, the embodiment of the present application discloses a specific method for measuring carbon dioxide concentration, which includes:

[0078] Step S21: vertically emitting a target high-energy pulse obtained after beam expansion of the original high-energy pulse into the atmosphere of the target area, and acquiring a Raman backscattering signal generated based on the target high-energy pulse, and then analyzing the Raman backscattering signal to obtain a vertical temperature profile and a vertical water vapor mixing ratio profile in the atmosphere in real time.

[0079] In an embodiment of the present application, a target high-energy pulse obtained after beam expansion of an original high-energy pulse is vertically emitted into the atmosphere of the target area, and a Raman backscattering signal generated based on the target high-energy pulse is obtained, and then the Raman backscattering signal is analyzed to obtain the vertical temperature profile and the vertical water vapor mixing ratio profile in the atmosphere in real time; in addition, the specific process of analyzing the Raman backscattering signal to obtain the vertical temperature profile and the vertical water vapor mixing ratio profile in the atmosphere in real time is: performing spectroscopic processing on the Raman backscattering signal to obtain target Raman signals corresponding to different preset wavelengths, and analyzing the target Raman signal to obtain the vertical temperature profile and the vertical water vapor mixing ratio profile in the atmosphere. It should be pointed out that the original high-energy pulse is 355nm. In addition, the spectroscopic unit obtains target Raman signals of 4 channels, namely 352.5nm, 353.9nm, 386.7nm and 407.5nm, after spectrometry. The temperature is calculated using the target Raman signals of 352.5nm and 353.9nm, and the water vapor mixing ratio is calculated using the target Raman signals of 386.7nm and 407.5nm. It should be pointed out that the Raman backscattering signal obtained based on the target high-energy pulse includes signals at each height.

[0080] Step S22: Determine in real time the target air molecule density, target carbon dioxide absorption cross-section difference, and target water vapor absorption cross-section difference at each height in the atmosphere of the target area based on the temperature vertical profile and the pressure vertical profile, and calculate the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile.

[0081] In this embodiment, regarding the specific process of the above step S22, reference may be made to the corresponding contents disclosed in the above embodiments, which will not be described in detail here.

[0082] Step S23: emitting the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide.

[0083] In this embodiment, for the specific process of the above step S23, reference may be made to the corresponding contents disclosed in the above embodiments, which will not be described again here.

[0084] Step S24: Calculate the target carbon dioxide concentration at the corresponding height according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference, so as to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

[0085] In this embodiment, regarding the specific process of the above step S24, reference may be made to the corresponding contents disclosed in the above embodiments, which will not be described in detail here.

[0086] It can be seen that the present application vertically emits a target high-energy pulse into the atmosphere of the target area, and obtains a Raman backscattering signal generated based on the target high-energy pulse, and then analyzes the Raman backscattering signal to obtain a temperature vertical profile and a water vapor mixing ratio vertical profile in the atmosphere in real time; based on the temperature vertical profile and the pressure vertical profile, the target air molecule density, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference at each height in the atmosphere of the target area are determined in real time, and the water vapor molecule density vertical profile is calculated based on the water vapor mixing ratio vertical profile; the original online wavelength and the original offline wavelength are emitted into the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide; the target carbon dioxide concentration at the corresponding height is calculated according to the water vapor molecule density vertical profile, the target online echo signal, the target offline echo signal, and the target air molecule density, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference at each height to obtain the carbon dioxide concentration vertical profile in the atmosphere of the target area. It can be seen that the present application obtains the temperature vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, calculates the target carbon dioxide absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and proposes to calculate the target water vapor absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and finally calculates the carbon dioxide concentration vertical profile based on the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference calculated in real time. Because the temperature vertical profile and the pressure vertical profile in the atmosphere are obtained in real time, the accuracy of carbon dioxide concentration measurement is improved; in addition, in the present application, the original high-energy pulse is expanded into a target high-energy pulse, and the obtained Raman backscattering signal is split to obtain target Raman signals of different preset wavelengths, which are used to calculate the temperature and water vapor molecule density respectively, thereby improving the accuracy of the calculation; in addition, the target water vapor absorption cross-section difference is calculated to eliminate the influence of the water vapor absorption cross-section difference on the carbon dioxide concentration calculation, thereby further improving the accuracy.

[0087] See also Figure 4 As shown, a carbon dioxide concentration measurement system is provided, which includes a Raman temperature and humidity laser radar module 11, a carbon dioxide differential absorption laser radar module 12, an acquisition control unit 13, a data fusion unit 14 and an air pressure sensor 15; the Raman temperature and humidity laser radar module 11 includes a Raman light source 110, a beam expander 111, a Raman receiving telescope 112, a spectrometer 113, a temperature Raman detection unit 114 and a water vapor Raman detection unit 115.

[0088] The Raman temperature and humidity laser radar module 11 is based on the Raman scattering principle and emits 355nm high-energy pulses vertically into the atmosphere. During the propagation of the pulses in the air, they are stimulated to generate Raman signals related to the atmospheric temperature and water vapor molecule density. A telescope is used to collect the Raman backscattered signals and analyze them to obtain vertical profile data of temperature and water vapor molecule number density. Specifically, the Raman light source 110 in the Raman temperature and humidity laser radar module 11 emits 355nm high-energy pulses, which are expanded by a beam expander 111 and then sent into the atmosphere. During the transmission of the pulse in the atmosphere, backscattered Raman signals related to temperature and water vapor are generated, which are received by the Raman receiving telescope 112 and enter the spectrometer unit 113 for spectrometry of Raman signals of 4 channels, namely 352.5nm, 353.9nm, 386.7nm and 407.5nm. The temperature Raman detection unit detects the 352.5nm and 353.9nm signals, and the water vapor Raman detection unit detects the 386.7nm and 407.5nm signals.

[0089] The CO2 differential absorption laser radar module 12 adopts differential absorption technology, or coherent differential absorption technology, and alternately emits ON wavelength laser and OFF wavelength laser at high frequency to the target atmosphere. The ON wavelength is located at the CO2 absorption peak, and the OFF wavelength is located at the CO2 absorption valley. The two wavelengths of laser enter the atmosphere and are absorbed by CO2 gas to varying degrees, and are scattered by atmospheric molecules and aerosols. The backscattered signal is received by the telescope and detected by the detector. The CO2 concentration information can be obtained by analyzing the difference between the two wavelength echo signals. Specifically, the CO2 differential absorption laser radar module 12 includes a dual-wavelength laser emitting unit 120, a CO2 transceiver telescope 121, and a CO2 detection unit 122. The dual-wavelength laser emitting unit 120 alternately emits ON wavelength laser and OFF wavelength laser, and emits vertically into the atmosphere through the CO2 transceiver telescope 121. The signal of the laser after being absorbed by CO2 gas in the atmosphere is backscattered by aerosols and atmospheric molecules, collected by the CO2 transceiver telescope 121, and transmitted to the CO2 detection unit 122 for photoelectric conversion. It should be pointed out that the CO2 differential absorption lidar module has a reserved data interface in the supporting software to receive real-time temperature, water vapor molecule density and other data from the outside, which is used to correct parameters such as absorption cross section and air molecule density.

[0090] The acquisition control unit 13 realizes the operation control and status monitoring of the Raman temperature and humidity laser radar module 11 and the CO2 differential absorption laser radar module 12, and the acquisition of Raman signals and differential absorption signals, and transmits the acquired signals to the data fusion module 14.

[0091] The air pressure sensor 15 measures the atmospheric pressure at the location of the system in real time.

[0092] The data fusion module 14 receives the temperature and water vapor Raman signals and CO2 differential absorption signals transmitted by the acquisition control module 13, calculates the temperature and water vapor mixing ratio profile data at each height, and uses them to correct the CO2 absorption cross-section difference, air molecule number density, water vapor molecule density, and water vapor interference at the corresponding height, and finally obtains the CO2 concentration by combining the CO2 differential absorption signal.

[0093] See also Figure 5 As shown in the figure, it is a schematic diagram of the carbon dioxide concentration measurement process; the pressure is measured by a pressure sensor, the temperature and water vapor molecule density are measured by a Raman temperature and humidity lidar, and the CO2 differential absorption lidar is used to obtain offline echo signals and online echo signals (two-wavelength echo signals). Then, the air molecule density, CO2 absorption cross-section difference and H2O absorption cross-section difference are calculated based on the temperature and pressure. Finally, the carbon dioxide concentration profile is calculated using the air molecule density, CO2 absorption cross-section difference, H2O absorption cross-section difference, water vapor molecule density offline echo signal and online echo signal.

[0094] It should be pointed out that this system includes a CO2 differential absorption lidar module and a Raman temperature and humidity lidar module. While measuring the CO2 differential absorption signal (online echo signal and offline echo signal), it can simultaneously measure the temperature and water vapor mixing ratio profile data of the same target area in real time, and then correct the CO2 absorption cross section, air molecule number density, water vapor molecule density, water vapor absorption cross section difference and other parameters to improve the CO2 inversion accuracy.

[0095] See also Figure 6 As shown, the embodiment of the present application discloses a carbon dioxide concentration measuring device, comprising:

[0096] A vertical profile acquisition module 11 is used to acquire the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, and determine the pressure vertical profile in the atmosphere of the target area;

[0097] An information determination module 12 is used to determine the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height in the atmosphere based on the temperature vertical profile and the pressure vertical profile, and calculate the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile;

[0098] The signal acquisition module 13 is used to transmit the original online wavelength and the original offline wavelength to the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide;

[0099] The carbon dioxide concentration calculation module 14 is used to calculate the target carbon dioxide concentration at the corresponding height according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference, so as to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

[0100] Among them, for more specific working processes of the above-mentioned modules, please refer to the corresponding contents disclosed in the aforementioned embodiments, which will not be repeated here.

[0101] It can be seen that the present application obtains the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, and determines the pressure vertical profile in the atmosphere of the target area; determines the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height in the atmosphere of the target area in real time based on the temperature vertical profile and the pressure vertical profile, and calculates the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile; emits the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide; calculates the target carbon dioxide concentration at the corresponding height according to the water vapor molecule density vertical profile, the target online echo signal, the target offline echo signal and the target air molecule density, the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference at each height to obtain the carbon dioxide concentration vertical profile in the atmosphere of the target area. It can be seen that the present application obtains the temperature vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, calculates the target carbon dioxide absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and proposes to calculate the target water vapor absorption cross-section difference in real time using the pressure vertical profile and the temperature vertical profile, and finally calculates the carbon dioxide concentration vertical profile based on the target carbon dioxide absorption cross-section difference and the target water vapor absorption cross-section difference calculated in real time. Because the temperature vertical profile and the pressure vertical profile in the atmosphere are obtained in real time, the accuracy of the carbon dioxide concentration measurement is improved; in addition, the target water vapor absorption cross-section difference is calculated to eliminate the influence of the water vapor absorption cross-section difference on the carbon dioxide concentration calculation, thereby further improving the accuracy.

[0102] Furthermore, an embodiment of the present application also provides an electronic device, Figure 7 This is a structural diagram of an electronic device 30 according to an exemplary embodiment. The content in the diagram cannot be regarded as any limitation on the scope of use of the present application.

[0103] Figure 7The present invention provides a schematic diagram of the structure of an electronic device 30 provided in an embodiment of the present application. The electronic device 30 may specifically include: at least one processor 31, at least one memory 32, a power supply 33, an input / output interface 34, a communication interface 35, and a communication bus 36. The memory 32 is used to store a computer program, which is loaded and executed by the processor 31 to implement the relevant steps of the carbon dioxide concentration measurement method disclosed in any of the aforementioned embodiments.

[0104] In this embodiment, the power supply 33 is used to provide working voltage for each hardware device on the electronic device 30; the communication interface 35 can create a data transmission channel between the electronic device 30 and the external device, and the communication protocol it follows is any communication protocol that can be applied to the technical solution of the present application, and is not specifically limited here; the input and output interface 34 is used to obtain external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs and is not specifically limited here.

[0105] In addition, the memory 32, as a carrier for resource storage, can be a read-only memory, a random access memory, a disk or an optical disk, etc. The memory 32 can include a random access memory as a running memory and a non-volatile memory for external memory storage purposes. The storage resources thereon include an operating system 321, a computer program 322, etc. The storage method can be temporary storage or permanent storage.

[0106] The operating system 321 is used to manage and control the hardware devices on the electronic device 30 on the source host and the computer program 322. The operating system 321 can be Windows, Unix, Linux, etc. In addition to the computer program that can be used to complete the carbon dioxide concentration measurement method performed by the electronic device 30 disclosed in any of the aforementioned embodiments, the computer program 322 can further include a computer program that can be used to complete other specific tasks.

[0107] In this embodiment, the input and output interface 34 may specifically include but is not limited to a USB interface, a hard disk reading interface, a serial interface, a voice input interface, a fingerprint input interface, etc.

[0108] Furthermore, an embodiment of the present application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the aforementioned disclosed method for measuring carbon dioxide concentration is implemented.

[0109] For the specific steps of the method, reference may be made to the corresponding contents disclosed in the aforementioned embodiments, which will not be described in detail here.

[0110] The computer-readable storage medium mentioned here includes random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, magnetic disk or optical disk or any other form of storage medium known in the technical field. Wherein, when the computer program is executed by the processor, the aforementioned carbon dioxide concentration measurement method is implemented. For the specific steps of the method, reference can be made to the corresponding contents disclosed in the aforementioned embodiments, which will not be repeated here.

[0111] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the carbon dioxide concentration measurement method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0112] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0113] The steps of the algorithm described in the embodiments disclosed herein can be implemented directly by hardware, software modules executed by a processor, or a combination of the two. The software module can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0114] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0115] The above is a detailed introduction to a method, device, equipment and medium for measuring carbon dioxide concentration provided by the present invention. Specific examples are used herein to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for a person skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for measuring carbon dioxide concentration, characterized in that: include: Based on the Raman scattering principle, the vertical profile of temperature and the vertical profile of water vapor mixing ratio in the atmosphere of the target area are obtained in real time, and the vertical profile of pressure in the atmosphere of the target area is determined; Determine in real time the target air molecule density, target carbon dioxide absorption cross section difference, and target water vapor absorption cross section difference at each height in the atmosphere of the target area based on the temperature vertical profile and the pressure vertical profile, and calculate the water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile; transmitting the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide; The target carbon dioxide concentration at the corresponding height is calculated according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

2. The method for measuring carbon dioxide concentration according to claim 1, characterized in that: The method of acquiring the vertical temperature profile and the vertical water vapor molecular density profile in the atmosphere of the target area in real time based on the Raman scattering principle includes: A target high-energy pulse obtained after beam expansion of the original high-energy pulse is vertically emitted into the atmosphere of the target area, and a Raman backscattering signal generated based on the target high-energy pulse is acquired. The Raman backscattering signal is then analyzed to obtain a vertical temperature profile and a vertical water vapor mixing ratio profile in the atmosphere in real time.

3. The method for measuring carbon dioxide concentration according to claim 2, characterized in that: The analyzing the Raman backscattering signal to obtain the vertical profile of the temperature and the vertical profile of the water vapor mixing ratio in the atmosphere in real time includes: The Raman backscattering signal is subjected to spectroscopic processing to obtain target Raman signals corresponding to different preset wavelengths, and the target Raman signal is analyzed to obtain a vertical profile of temperature and a vertical profile of water vapor mixing ratio in the atmosphere.

4. The method for measuring carbon dioxide concentration according to claim 1, characterized in that: The real-time emission of the original online wavelength and the original offline wavelength into the atmosphere of the target area to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide includes: The original online wavelength and the original offline wavelength are vertically emitted in real time into the atmosphere of the target area to obtain target online echo signals and target offline echo signals at various heights after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide.

5. The method for measuring carbon dioxide concentration according to claim 1, characterized in that: The real-time emission of the original online wavelength and the original offline wavelength into the atmosphere of the target area to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide includes: Transmitting multiple groups of original online wavelengths and original offline wavelengths vertically into the atmosphere of the target area in real time, and acquiring original online echo signals and original offline echo signals at each height corresponding to each group of the original online wavelengths and the original offline wavelengths; An average value of the original online echo signal and an average value of the original offline echo signal at each height are calculated to obtain a target online echo signal and a target offline echo signal.

6. The method for measuring carbon dioxide concentration according to claim 1, characterized in that: The calculating the vertical profile of water vapor molecule density based on the vertical profile of water vapor mixing ratio comprises: Calculating a water vapor volume mixing ratio vertical profile based on the water vapor mixing ratio vertical profile; The target water vapor molecule density at each altitude is calculated based on the water vapor volume mixing ratio vertical profile and the target air molecule density at each altitude to obtain a water vapor molecule density vertical profile.

7. The method for measuring carbon dioxide concentration according to any one of claims 1 to 6, characterized in that: Determining the vertical pressure profile in the atmosphere of the target area includes: The target pressure at the location of the air pressure sensor is measured by the air pressure sensor, and the pressure at each height in the atmosphere of the target area is calculated based on the target pressure and a target standard atmosphere model to determine the vertical pressure profile in the atmosphere of the target area.

8. A device for measuring carbon dioxide concentration, characterized in that: include: A vertical profile acquisition module is used to acquire the temperature vertical profile and the water vapor mixing ratio vertical profile in the atmosphere of the target area in real time based on the Raman scattering principle, and determine the pressure vertical profile in the atmosphere of the target area; an information determination module, for determining a target air molecule density, a target carbon dioxide absorption cross-section difference, and a target water vapor absorption cross-section difference at each height in the atmosphere based on the temperature vertical profile and the pressure vertical profile, and calculating a water vapor molecule density vertical profile based on the water vapor mixing ratio vertical profile; A signal acquisition module, used for transmitting the original online wavelength and the original offline wavelength into the atmosphere of the target area in real time to obtain the target online echo signal and the target offline echo signal at each height after the original online wavelength and the original offline wavelength are absorbed by carbon dioxide; The carbon dioxide concentration calculation module is used to calculate the target carbon dioxide concentration at the corresponding height according to the vertical profile of the water vapor molecule density, the target online echo signal, the target offline echo signal, the target air molecule density at each height, the target carbon dioxide absorption cross-section difference, and the target water vapor absorption cross-section difference, so as to obtain the vertical profile of the carbon dioxide concentration in the atmosphere of the target area.

9. An electronic device, characterized in that: It comprises a processor and a memory; wherein, when the processor executes the computer program stored in the memory, the carbon dioxide concentration measurement method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: Used to store a computer program; wherein, when the computer program is executed by a processor, the carbon dioxide concentration measurement method according to any one of claims 1 to 7 is implemented.

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