Method for simultaneously detecting 80-100km temperature and wind field and 0-30km wind field based on satellite-borne iron laser radar
Through the satellite-based iron lidar, 372nm laser was emitted and combined with Doppler principle and bilateral frequency identification method, the problem of multi-level detection in the satellite-based wind measurement technology was solved, and high-precision detection of wind fields and temperatures of 80-100km and 0-30km was achieved, which promoted the development of satellite-based iron radar.
Patent Information
- Application Number
- CN202510829588.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-20
- Publication Date
- 2025-08-01
AI Technical Summary
The existing satellite-based wind measurement technology can only detect wind fields at the same height at the same time and lacks multi-level detection capabilities.
The satellite-borne iron lidar emits a laser with a wavelength of 372nm, uses iron atom resonance fluorescence effect and Doppler principle, and combines the bilateral frequency identification method to achieve simultaneous detection of wind fields and temperatures of 80-100km and 0-30km.
It realizes high-precision acquisition of wind field and temperature profile information throughout the day and all day, supports the development of satellite-based iron radar, and promotes the development process of loads.
Smart Images
Figure CN120405705A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of atmospheric remote sensing technology, and particularly to a method for simultaneously detecting the temperature and wind field at 80 - 100 km and the wind field at 0 - 30 km based on spaceborne iron lidar. Background Art
[0002] Currently, satellites and payloads capable of obtaining the temperature and wind speed at an altitude of 80 - 100 km include Aura / MLS, TIMED / SABER, and ICON / MIGHTI of the United States. However, these detection technologies are mainly based on passive remote sensing methods, with disadvantages such as relying on sunlight and having low vertical resolution. As an active remote sensing means, lidar has the advantages of all-day and all-weather high-precision detection and can be used as a payload to detect the global atmospheric environment.
[0003] As a new type of atmospheric sounding payload, spaceborne lidar can provide global high-precision vertical distribution information and can conduct continuous day and night observations. The World Meteorological Organization regards spaceborne wind lidar as the primary development technology direction for obtaining global wind field information. The wind lidar emits laser of a certain wavelength into the atmosphere and receives the backscattering signals of atmospheric aerosol particles and atmospheric molecules. By analyzing the radial Doppler shift of the laser, the wind speed is retrieved. From the detection method, it can be divided into coherent and incoherent detection lidars. The incoherent detection method is also called direct detection. As early as 1979, the United States proposed a scheme for spaceborne incoherent wind lidar and conducted simulation analysis. Subsequently, in 1985, it proposed the LAWS (Laser atmospheric wind sounder) plan. The coherent wind Doppler lidar with a wavelength of 2 microns was used in this plan, but this plan was stopped due to the limitations of technology development at that time. In 2007, the United States proposed a wind lidar scheme with a hybrid system. This plan is called GWOS (Global wind observing system). This plan combines the two technologies and demonstrates this technology through simulation. Japan has carried out a series of studies on the Doppler wind lidar JEM / CDL (Japanese experiment module / Coherent Doppler lidar) since 1998, carrying the coherent technology on the International Space Station, aiming to detect the wind field within the boundary layer and within clouds. What really successfully launched the wind lidar was the Atmospheric Dynamics Mission (ADM) launched by the European Space Agency in 1999. Its detection target is the vertical distribution characteristics of the wind field from the ground to the stratosphere. The Aeolus satellite carried the Atmospheric Laser Doppler Wind Lidar (ALADIN) and successfully entered the sun-synchronous orbit on August 22, 2018. ALADIN uses a Mie scattering channel based on a Fizeau interferometer and a Rayleigh scattering detection channel with a dual FP etalon. The successful completion of the ALADIN mission confirmed the feasibility of spaceborne wind lidar, and the Aeolus-2 plan will also continue.
[0004] Based on the above content, the following problems are found: According to the international spaceborne wind sounding technology, it can only detect the wind field at the same altitude at the same time, and it is not difficult to find that the detection altitude is relatively single. Summary of the Invention
[0005] Based on this, it is necessary to provide a method for simultaneously detecting the temperature and wind field at 80 - 100 km and the wind field at 0 - 30 km based on spaceborne iron lidar to solve the above technical problems, which can simultaneously detect the wind field and temperature at 0 - 30 km and 80 - 100 km.
[0006] A method for simultaneously detecting the temperature and wind field in the 80 - 100 km altitude range and the wind field in the 0 - 30 km altitude range based on spaceborne iron lidar provided by this application includes: Using the spaceborne iron lidar to emit laser with a wavelength of 372 nm into the UMLT region of the atmosphere, and calculating the number of echo photons generated by the iron atom resonance fluorescence effect received; Defining a temperature response function and a wind speed response function according to the number of echo photons, calculating the atmospheric temperature in the 80 - 100 km region according to the temperature response function, and calculating the atmospheric wind speed in the 80 - 100 km region according to the wind speed response function; Calculating the radial wind speed of the atmosphere in the 0 - 30 km altitude range based on the Doppler principle according to the number of echo photons; among them, calculating the radial wind speed of the atmosphere in the 0 - 30 km altitude range based on the Doppler principle according to the number of echo photons includes: Using the dual - edge frequency discrimination method to construct the response function of the system based on the number of echo photons; Calculating the radial wind speed of the atmosphere in the 0 - 30 km altitude range based on the response function.
[0007] In one embodiment, the formula for calculating the number of echo photons generated by the iron atom resonance fluorescence effect received is as follows:
[0008] Among them, is the emission power of the laser; is the integration time; h is Planck's constant; c is the speed of light; is the wavelength emitted by the laser; is the differential cross - section of iron resonance fluorescence backscattering; is the number density of iron atoms in the WACCM atmospheric model; z is the distance from the detection target to the ground; is the orbital altitude of the satellite platform; is the vertical resolution; A is the area of the receiving telescope; is the total efficiency of the system, including the quantum efficiency of the detector and the optical efficiency of the system; G is the geometric factor of the lidar system; is the transmittance of the iron layer to the optical signal; is the transmittance of atmospheric molecules; is the noise.
[0009] In one embodiment, the calculation formula for the differential cross - section of iron resonance fluorescence backscattering is as follows:
[0010]
[0011]
[0012] Among them, e is the electric charge, is the oscillator strength; is the vacuum permittivity; is the electron mass; f Fe is the center frequency of the ferromagnetic resonance absorption line; f is the observed fluorescence photon frequency; k B is the Boltzmann constant; T is the atmospheric temperature; M Fe is the iron atom mass; is the Doppler broadening; σ L is the linewidth of the output laser; A n is the relative abundance of the stable isotope; is the effective scattering cross section considering the Fe atom and the laser linewidth.
[0013] In one embodiment, the 372 nm laser has three different frequencies, which are respectively defined as f 0, f + and f - , where:
[0014] wherein, δf represents the frequency adjustment amount; Define the temperature response function based on the number of echo photons R T and the wind speed response function R V , and the formula is as follows:
[0015]
[0016] wherein, is the wavelength emitted by the laser.
[0017] In one embodiment, calculate the atmospheric temperature in the 80 - 100 km region according to the temperature response function, and the formula is as follows:
[0018]
[0019] where T is the atmospheric temperature; δf is the frequency adjustment amount; is the Doppler broadening; σ L is the linewidth of the output laser; M Feis the mass of an iron atom; is the wavelength emitted by the laser; is an intermediate parameter.
[0020] In one embodiment, calculating the atmospheric temperature in the 80 - 100 km region according to the temperature response function further includes calculating the random error of the atmospheric temperature. The formula is as follows:
[0021]
[0022] where, Δ T night is the random error of the atmospheric temperature detected by the night spaceborne iron lidar in the 80 - 100 km region; Δ T day is the random error of the atmospheric temperature detected by the day spaceborne iron lidar in the 80 - 100 km region; is ; ψ is the proportion time; SNR 0 is the signal ratio of the lidar.
[0023] In one embodiment, calculating the atmospheric wind speed in the 80 - 100 km region according to the wind speed response function, the formula is as follows:
[0024] where, V R is the atmospheric wind speed; is the wavelength emitted by the laser; δf represents the frequency adjustment amount.
[0025] In one embodiment, calculating the atmospheric wind speed according to the wind speed response function further includes calculating the random error of the atmospheric wind speed. The formula is as follows:
[0026]
[0027] where, ΔV R-night is the random error of the wind speed detected by the night spaceborne iron lidar in the UMLT region, and ΔV R-day is the random error of the wind speed detected by the day spaceborne iron lidar in the UMLT region.
[0028] In one embodiment, calculating the atmospheric radial wind speed in the 0 - 30 km region based on the response function includes: Calculating the sensitivity of the frequency discriminator. The formula is as follows:
[0029] Calculate the radial wind speed in the 0 - 30 km area based on the sensitivity of the discriminator and the Doppler frequency quantity. The formula is as follows:
[0030] where v is the frequency; is the response function corresponding to the frequency; c is the speed of light; and are the sensitivities of the two channels of the discriminator respectively; is the response function value that generates the Doppler frequency shift; is the response function value without generating the Doppler frequency shift.
[0031] In one embodiment, the method further includes: calculating the wind speed error in the 0 - 30 km area according to the total signal - to - noise ratio of the system. The formula is as follows:
[0032]
[0033] where, is the total signal - to - noise ratio of the system; is the wind speed error in the 0 - 30 km area; and are the signal - to - noise ratios of the two channels of the discriminator respectively.
[0034] This application adopts the above - mentioned method for simultaneously detecting the temperature and wind field in the 80 - 100 km area and the wind field in the 0 - 30 km area based on space - borne iron lidar, and has the following beneficial effects: The method provided by this application is based on space - borne iron lidar to simultaneously detect the atmospheric parameters in the 0 - 30 km and 80 - 100 km areas, and can obtain the wind field and temperature profile information with high precision all day and all weather. This method has reference value for the development of space - borne resonance fluorescence Doppler lidar for detecting atmospheric wind speed and temperature profile, provides theoretical basis support for the development of space - borne iron lidar, and accelerates the research and development process of the payload. Brief Description of the Drawings
[0035] Figure 1 is a schematic diagram of a method for simultaneously detecting the temperature and wind field in the 80 - 100 km area and the wind field in the 0 - 30 km area based on space - borne iron lidar in one embodiment; Figure 2 is a schematic diagram of the backscattering coefficient and extinction coefficient of particles and the transmittance of atmospheric molecules in one embodiment; among them, (a) is a schematic diagram of the backscattering coefficient and extinction coefficient of atmospheric molecules at a wavelength of 372 nm; (b) is a schematic diagram of the backscattering coefficient and extinction coefficient of aerosols at a wavelength of 372 nm; (c) is a schematic diagram of the transmittance of atmospheric molecules; Figure 3Schematic diagram of the double Fabry-Perot simulation design in an embodiment; among them, (a) shows the variation of wind speed error with different full widths at half maximum and peak-to-peak spacing; (b) shows the wind speed error corresponding to different full widths at half maximum; (c) shows the detection sensitivity of FP to atmospheric molecules and aerosol molecules. Figure 4 Schematic diagram of the variation curves of wind speed and temperature errors with altitude in the altitude range of 80 - 100 km in an embodiment; among them, (a) shows the wind speed error; (b) shows the temperature error. Figure 5 Schematic diagram of the variation curve of wind speed error with altitude in the altitude range of 0 - 30 km in an embodiment. Detailed implementation manners
[0036] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0037] The active remote sensing detection method of lidar has obvious advantages. The purpose of this research is to use the laser with a wavelength of 372 nm emitted by lidar, and use the iron atoms in the atmospheric metal layer as a tracer. The laser of this wavelength is exactly located on the characteristic absorption spectrum line of iron atoms. The iron atoms in the atmosphere absorb photons and transition to the ground state through spontaneous emission to generate resonance fluorescence. After interaction, Doppler frequency shift and Doppler broadening are generated to obtain the information of the wind field and temperature in the 80 - 100 km region of the atmosphere. At the same time, the laser in the ultraviolet band is used to generate Rayleigh scattering with atmospheric molecules to obtain the atmospheric wind speed from the near ground to the stratosphere. By combining the two mechanisms, the atmospheric wind field and temperature information in the 80 - 100 km and 0 - 30 km altitude ranges of the earth's atmosphere can be obtained simultaneously.
[0038] In this embodiment, the parameters of the lidar are shown in Table 1 below: Table 1 Design parameters of the spaceborne iron resonance fluorescence Doppler lidar
[0039] Based on the above lidar, a method for simultaneously detecting the temperature and wind field in the 80 - 100 km altitude range and the wind field in the 0 - 30 km altitude range based on a spaceborne iron lidar provided by the present application includes: S100, using the spaceborne iron lidar to emit a laser with a wavelength of 372 nm into the atmospheric UMLT region, and calculating the number of echo photons generated by the received iron atom resonance fluorescence effect.
[0040] In an embodiment, the formula for receiving the number of iron atom resonance fluorescence echo photons generated by the UMLT region is as follows:
[0041] Among them, is the emission power of the laser; is the integration time; h is Planck's constant; c is the speed of light; is the wavelength emitted by the laser; is the differential cross section of the backward scattering of iron resonance fluorescence; is the number density of iron atoms in the WACCM atmospheric model; z is the distance from the detection target to the ground; is the orbital altitude of the satellite platform operation; is the vertical resolution; A is the area of the receiving telescope; is the total system efficiency, including the quantum efficiency of the detector and the optical efficiency of the system; G is the geometric factor of the lidar system; is the transmittance of the iron layer to the optical signal; is the transmittance of atmospheric molecules; is the noise.
[0042] In one embodiment, the calculation formula of the differential cross section of the backward scattering of iron resonance fluorescence is as follows:
[0043]
[0044]
[0045] Among them, e is the electric charge amount, is the oscillator strength; is the vacuum permittivity; is the electron mass; f Fe is the center frequency of the iron resonance absorption line; f is the observed fluorescence photon frequency; k B is the Boltzmann constant; T is the atmospheric temperature; M Fe is the iron atom mass; is the Doppler broadening; σ L is the line width of the emitted laser; A n is the relative abundance of stable isotopes; is the effective scattering cross section considering the Fe atom and the laser line width.
[0046] S200, define the temperature response function and the wind speed response function according to the number of echo photons, calculate the atmospheric temperature in the 80 - 100 km region according to the temperature response function, and calculate the atmospheric wind speed in the 80 - 100 km region according to the wind speed response function.
[0047] In one embodiment, the 372 nm laser has three different frequencies, which are respectively defined as f 0, f + and f - , where:
[0048] Among them, δf represents the frequency adjustment amount; The temperature response function is defined based on the number of echo photons R T and the wind speed response function R V , and the formula is as follows:
[0049]
[0050] Among them, is the wavelength emitted by the laser.
[0051] In one embodiment, the temperature response function calculates the atmospheric temperature in the 80 - 100 km region, and the formula is as follows:
[0052]
[0053] Among them, T is the atmospheric temperature; δf is the frequency adjustment amount; is the Doppler broadening; σ L is the line width of the emitted laser; M Fe is the mass of the iron atom; is the wavelength emitted by the laser; is an intermediate parameter.
[0054] In one embodiment, calculating the atmospheric temperature according to the temperature response function T also includes calculating the random error of the atmospheric temperature, and the formula is as follows:
[0055]
[0056] Among them, Δ T night is the random error of the atmospheric temperature detected by the night spaceborne iron lidar in the 80 - 100 km region; Δ T day is the random error of the atmospheric temperature detected by the day spaceborne iron lidar in the 80 - 100 km region; is ; ψ is the proportion time; SNR 0 is the signal ratio of the lidar.
[0057] In one embodiment, the atmospheric wind speed in the 80 - 100 km region is calculated according to the wind speed response function, and the formula is as follows:
[0058] Wherein, V R is the atmospheric wind speed; is the wavelength emitted by the laser; δf is the frequency adjustment amount.
[0059] In one embodiment, calculating the atmospheric wind speed in the 80 - 100 km region according to the wind speed response function further includes calculating the random error of the atmospheric wind speed in the 80 - 100 km region, and the formula is as follows:
[0060]
[0061] Wherein, ΔV R-night is the random error of the wind speed detected by the night spaceborne iron lidar in the UMLT region, and ΔV R-day is the random error of the wind speed detected by the day spaceborne iron lidar in the UMLT region.
[0062] S300, calculate the 0 - 30 km atmospheric radial wind speed based on the Doppler principle according to the number of echo photons.
[0063] In one embodiment, calculating the 0 - 30 km atmospheric radial wind speed based on the Doppler principle according to the number of echo photons includes: Using the dual - edge frequency discrimination method to construct the response function of the system based on the backscattering signal, and the formula is as follows:
[0064] Wherein, R is the response function of the system; N1 and N2 are the number of echo photons finally detected by the two channels of the dual - edge frequency discrimination method respectively; Calculate the 0 - 30 km atmospheric radial wind speed based on the response function.
[0065] In one embodiment, the formula for the number of photons is as follows:
[0066] Wherein, E is the energy of a single pulse emitted by the laser; is the wavelength emitted by the laser; is the total efficiency of the system; h is Planck's constant; c is the speed of light; k is the system constant term; and are the backscattering coefficients of aerosol and atmospheric molecules, respectively; and are the extinction coefficients of aerosol and atmospheric molecules, respectively; f a and f m are the transmittances of aerosol and atmospheric molecules after passing through the discriminator, respectively, which are obtained by convolving the scattering spectral line with the FP transmittance spectral line. The formula is as follows:
[0067]
[0068]
[0069]
[0070]
[0071] where f R is the transmittance curve of FP; h m and h a are the scattering spectra of atmospheric molecules and aerosol, respectively; v is the frequency; k B is the Boltzmann constant; T is the atmospheric temperature; f Fe is the center frequency of the iron resonance absorption line; M m is the mass of a single atmospheric molecule; σ L is the linewidth of the outgoing laser; is the integration variable corresponding to the frequency; is the Rayleigh broadening, that is, the Doppler broadening of atmospheric molecules; is the effective spectral broadening, that is, the combined broadening; is the laser spectral width.
[0072] The method of incoherent Doppler frequency shift detection can directly calculate the Doppler frequency shift through the photon number or light intensity of the frequency discriminator. Currently, the commonly used frequency discriminators include Fabry-Perot frequency discriminator, Fizeau frequency discriminator, and iodine molecular frequency discriminator. The double-edge frequency discrimination method adopted in this study follows the basic advantages of the single-edge technology and has better performance. The principle is that if the frequency of the atmospheric backscattering signal has a Doppler frequency shift relative to the initial laser frequency, the transmitted signals of both filters will change. For two filters with the same performance, the corresponding signal changes are approximately equal in magnitude and opposite in sign. By measuring the signal changes, the Doppler frequency of the backscattered light can be inversely calculated, and then the atmospheric radial wind speed can be obtained.
[0073] In one embodiment, calculating the 0 - 30 km atmospheric radial wind speed based on the response function includes: Calculating the sensitivity of the frequency discriminator, and the formula is as follows:
[0074] Calculating the radial wind speed in the 0 - 30 km area based on the sensitivity of the frequency discriminator and the Doppler frequency amount, and the formula is as follows:
[0075] where \(v\) is the frequency; is the response function corresponding to the frequency; c is the speed of light; and are the sensitivities of the two channels of the frequency discriminator respectively; is the response function value that generates the Doppler frequency shift; is the response function value without generating the Doppler frequency shift.
[0076] In one embodiment, the method further includes: calculating the wind speed error in the 0 - 30 km area according to the total signal-to-noise ratio of the system, and the formula is as follows:
[0077]
[0078] where, is the total signal-to-noise ratio of the system; is the wind speed error in the 0 - 30 km area; and are the signal-to-noise ratios of the two channels of the frequency discriminator respectively.
[0079] The random error dominated by optical quantum noise in the spaceborne iron lidar is the most significant influencing factor and is closely related to the lidar payload system parameters. Assuming that the number of received echo photons is \(N\) and follows a Poisson distribution, then the optical quantum noise count is approximately In the simulation of spaceborne iron lidar, the relationship between measurement error and system parameters is quantitatively established using the lidar equation, thereby guiding the design of the lidar payload system and reducing the influence of random errors.
[0080] Refer to Figures 2 to 5 , Figure 2 In (a) of [], the variation of the atmospheric molecular backscattering coefficient and extinction coefficient with height at a wavelength of 372 nm obtained from the temperature and pressure of the US standard atmosphere model is shown. It can be seen that the coefficient changes by approximately two orders of magnitude from the ground to 30 km. Figure 2 In (b) of [], the backscattering coefficient and extinction coefficient of aerosols at a wavelength of 372 nm obtained from the RMA model are shown. It can be seen that the backscattering coefficient and extinction coefficient of RMA aerosols after wavelength conversion change by approximately four orders of magnitude in the height range of 0 - 30 km. Figure 2 In (c) of [], the atmospheric transmittance in the height range of 0 - 30 km under the spaceborne platform obtained from the extinction coefficients of atmospheric molecules and aerosols is shown. The atmospheric transmittance gradually increases with the increase of height and approaches 1 at 25 km.
[0081] Figure 3 The simulation design of the full width at half maximum and peak - to - peak spacing parameters of the double - FP. As Figure 3 shown in (a) of [], the variation of the single - pulse wind measurement error with the full width at half maximum and peak - to - peak spacing of the FP interferometer is simulated and calculated during daytime measurement and in the case of pure Rayleigh scattering. It can be seen from the figure that the minimum value of the measurement error appears in a nearly elliptical region. When the full width at half maximum is fixed, the wind speed error first decreases and then increases with the increase of the peak - to - peak spacing value. Refining the analysis of the corresponding ellipse in (a) of Figure 3 , taking values near 1.6 GHz and simulating with an adjacent interval of 200 MHz, the result is as shown in (b) of Figure 3 . As the full width at half maximum of the FP interferometer gradually increases, the measurement error of the system also shows a trend of first decreasing and then increasing. When the full width at half maximum of the FP interferometer is 1.6 GHz, the wind speed error is the smallest, so the parameter of the full width at half maximum is determined. For the signal of the mixture of atmospheric molecules and aerosols, Chanin et al. proposed the theory of special operating points. Based on the double - edge detection technology, the peak - to - peak spacing of two FP interferometers is configured so that the FP interferometer has the same detection sensitivity to the atmospheric molecular scattering signal and the aerosol scattering signal. The result in (c) of Figure 3 is obtained through simulation calculation. Point A is the special operating point, and the corresponding peak - to - peak spacing is 5.1 GHz. The sensitivity of the two signals is the same at 0.0077 m / s here. This design makes it possible for the spaceborne iron lidar to detect the wind fields at high and low altitudes simultaneously.
[0082] Figure 4The wind speed and temperature errors at 80 - 100 km calculated based on the principle of resonance fluorescence are shown. It can be seen that both the wind speed and temperature errors show a trend of first decreasing and then increasing. The wind speed error at night is 1.59 m / s, and the temperature error is 3.16 K.
[0083] Figure 5 The wind speed error at 0 - 30 km calculated based on the principle of Rayleigh scattering. The change of the wind speed error in the height range of 0 - 30 km generally shows a trend of first decreasing and then increasing. In the range of 0 - 2 km, the wind speed error is 2.2 - 3.4 m / s. In the range of 2 - 16 km, the wind speed error is 1.4 - 2.2 m / s. In the range of 16 - 30 km, the wind speed error is 1.7 - 4.4 m / s.
[0084] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.
[0085] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.
Claims
1. A method for simultaneously detecting the temperature and wind field at 80 - 100 km and the wind field at 0 - 30 km based on spaceborne iron lidar, characterized in that, Including: Emitting laser with a wavelength of 372 nm to the atmospheric UMLT region by spaceborne iron lidar, and calculating the number of echo photons generated by the received iron atom resonance fluorescence effect; Defining a temperature response function and a wind speed response function according to the number of echo photons, calculating the atmospheric temperature in the 80 - 100 km region according to the temperature response function, and calculating the atmospheric wind speed in the 80 - 100 km region according to the wind speed response function; Calculating the radial wind speed of the atmosphere from 0 to 30 km based on the Doppler principle according to the number of echo photons; wherein, calculating the radial wind speed of the atmosphere from 0 to 30 km based on the Doppler principle according to the number of echo photons includes: Constructing the response function of the system based on the number of echo photons using the dual - edge frequency discrimination method; Calculating the radial wind speed of the atmosphere from 0 to 30 km based on the response function.
2. The method according to claim 1, wherein The formula for calculating the number of echo photons generated by the received iron atom resonance fluorescence effect is as follows: Among them, is the emission power of the laser; is the integration time; h is Planck's constant; c is the speed of light; is the wavelength emitted by the laser; is the differential cross section of the backward scattering of the iron resonance fluorescence; is the number density of iron atoms in the WACCM atmospheric model; z is the distance from the detection target to the ground; is the orbital altitude of the satellite platform operation; is the vertical resolution; A is the area of the receiving telescope; is the total system efficiency, including the quantum efficiency of the detector and the optical efficiency of the system; G is the geometric factor of the lidar system; is the transmittance of the iron layer to the optical signal; is the transmittance of the atmospheric molecules; is the noise.
3. The method according to claim 2, wherein The formula for calculating the differential cross - section of iron resonance fluorescence backscattering is as follows: where e is the electric charge, is the oscillator strength; is the vacuum permittivity; is the electron mass; f Fe is the central frequency of the ferromagnetic resonance absorption line; f is the observed fluorescence photon frequency; k B is the Boltzmann constant; T is the atmospheric temperature; M Fe is the iron atom mass; is the Doppler broadening; σ L is the linewidth of the output laser; A n is the relative abundance of the stable isotope; is the effective scattering cross section considering the Fe atom and the laser linewidth.
4. The method according to claim 3, characterized in that, The 372 nm laser has three different frequencies, which are respectively defined as f 0, f + and f - , where: Among them, δf represents the frequency adjustment amount; Define the temperature response function based on the number of echo photons R T and the wind speed response function R V , and the formula is as follows: Among them, is the wavelength emitted by the laser.
5. The method according to claim 4, characterized in that, Calculating the atmospheric temperature in the 80 - 100 km region according to the temperature response function, the formula is as follows: Among them, T is the atmospheric temperature; δf is the frequency adjustment amount; is the Doppler broadening; σ L is the line width of the emitted laser; M Fe is the mass of the iron atom; is the wavelength emitted by the laser; is an intermediate parameter.
6. The method according to claim 5, characterized in that Calculating the atmospheric temperature in the 80 - 100 km region according to the temperature response function also includes calculating the random error of the atmospheric temperature, the formula is as follows: Among them, Δ T night is the random error of the atmospheric temperature detected by the spaceborne iron lidar in the 80 - 100 km region at night; Δ T day is the random error of the atmospheric temperature detected by the spaceborne iron lidar in the 80 - 100 km region during the day; is ; ψ is the proportion time; SNR 0 is the signal ratio of the lidar.
7. The method according to claim 4, wherein Calculating the atmospheric wind speed in the 80 - 100 km region according to the wind speed response function, the formula is as follows: Among them, V R is the atmospheric wind speed; is the wavelength emitted by the laser; δf is the frequency adjustment amount.
8. The method according to claim 1, characterized in that Calculating the radial wind speed of the atmosphere from 0 to 30 km based on the response function includes: Calculating the sensitivity of the frequency discriminator, the formula is as follows: Calculating the radial wind speed in the 0 - 30 km region based on the sensitivity of the frequency discriminator and the response function, the formula is as follows: where, v is the frequency; is the response function corresponding to the frequency; c is the speed of light; and are the sensitivities of the two channels of the frequency discriminator, respectively; is the response function value that generates the Doppler frequency shift; is the response function value without generating the Doppler frequency shift.
9. The method according to claim 8, wherein Also including: Calculating the wind speed error in the 0 - 30 km region according to the total signal - to - noise ratio of the system, the formula is as follows: Among them, is the total signal-to-noise ratio of the system; is the wind speed error in the 0 - 30 km area; and are the signal-to-noise ratios of the two channels of the discriminator respectively.