Meteorological element inversion method, device, equipment and medium

Abstract

The present invention relates to the field of meteorological detection, and discloses a meteorological element inversion method, device, equipment and medium, including: receiving two groups of atmospheric echo signals of a Doppler laser radar using a dual-wavelength emission mechanism; the two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules; performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information, extracting their peak values ​​as backscattering power signals, and calculating the backscattering coefficients of aerosols at different heights measured by the two wavelengths; obtaining a relationship model between the ratio of the backscattering coefficients measured by the two wavelengths and the average diameter of raindrops on the ground, and inverting the raindrop spectrum distribution information at different heights. The present invention adopts a dual-wavelength emission mechanism Doppler laser radar, which has the advantages of high temporal and spatial resolution, small size and low cost, and can use the different absorption characteristics of different wavelengths for water to measure aerosol optical characteristics and invert raindrop spectrum distribution information.

Description

Technical Field

[0001] The present invention relates to the field of meteorological detection, and in particular to a meteorological element inversion method, device, equipment and medium. Background Art

[0002] The rainfall process is an important part of the global water cycle. The microscopic physical properties of rainfall, including raindrop size, shape, speed and size distribution, are of great significance to application fields such as aviation safety, weather forecasting, agricultural production, and flood prevention.

[0003] Rainfall observation methods that are widely used include rain gauges, raindrop spectrometers and other measuring instruments, but these measuring instruments can only obtain ground raindrop spectrum data. In order to obtain a higher level of raindrop spectrum information on the ground, balloons are usually released artificially or sounding sensors are brought into the air by aircraft to measure the rainfall characteristic profile, but the time resolution is low and the price is high. In addition, radars are also used for measurement. The radars mainly include weather radars based on microwave or radio wavelengths, micro-rain radars, wind profile radars, etc., but weather radars are large in size and expensive. Micro-rain radars can only detect rainfall, but cannot detect aerosols and wind speed, and wind profile radars cannot directly measure rain. Summary of the invention

[0004] The purpose of the present invention is to provide a meteorological element inversion method, device, equipment and medium, which has the advantages of high temporal and spatial resolution, small size and low cost. It can measure the optical properties of aerosols by utilizing the different absorption characteristics of water at different wavelengths, and invert the raindrop spectrum distribution information at different heights.

[0005] In order to solve the above technical problems, the present invention provides a meteorological element inversion method, comprising:

[0006] receiving two sets of atmospheric echo signals from a Doppler laser radar using a dual-wavelength emission mechanism; the two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules;

[0007] Performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information;

[0008] Extracting peak values ​​of the two sets of coherent spectrum information as backscattering power signals, and calculating backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signals;

[0009] The relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground is obtained, and the relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factor of different wavelengths is combined to invert the raindrop spectrum distribution information at different heights.

[0010] In a first aspect, the above-mentioned meteorological element inversion method provided by the present invention further includes:

[0011] The radial component of the wind speed is calculated according to the Doppler frequency shift and wavelength corresponding to the two groups of atmospheric echo signals;

[0012] The wind speed and direction information is inverted according to the radial component of the wind speed.

[0013] On the other hand, in the above-mentioned meteorological element inversion method provided by the present invention, coherent frequency detection and fast Fourier transform are performed on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information, including:

[0014] The two groups of atmospheric echo signals are subjected to relevant frequency detection, and the frequencies of the two groups of atmospheric echo signals obtained by detection are respectively and ;in, is the laser emission center frequency corresponding to the first wavelength; is the laser emission center frequency corresponding to the second wavelength; Frequency shift for acousto-optic modulation; for The corresponding frequency shift caused by the movement of atmospheric aerosol particles; for The corresponding frequency shift caused by the movement of atmospheric aerosol particles;

[0015] The two groups of atmospheric echo signals are converted into electrical signals, and after the electrical signals are collected and divided into range gates, fast Fourier transform is performed to obtain two groups of related frequency spectrum information.

[0016] On the other hand, in the above-mentioned meteorological element inversion method provided by the present invention, the backscattering coefficients of aerosols at different heights measured at two wavelengths are calculated according to the backscattering power signal, including:

[0017] For each wavelength, the backscatter coefficient of the first range gate is obtained by using the initial extinction coefficient of the horizontal measurement and the backscatter power signal energy of the first range gate;

[0018] According to the backscattering coefficient of the first range gate, the extinction coefficient of the first range gate is calculated;

[0019] Iterating the extinction coefficient of the first range gate into the second range gate, combining the backscatter power signal energy of the second range gate, and obtaining the backscatter coefficient of the second range gate;

[0020] The extinction coefficient is re-executed and the calculation step of the next range gate is iterated until the backscattering coefficients of all range gates are obtained.

[0021] On the other hand, in the above-mentioned meteorological element inversion method provided by the present invention, the backscatter coefficient of each range gate is obtained by using the following formula:

[0022] ;

[0023] ;

[0024] ;

[0025] ;

[0026] ;

[0027] in, is the wavelength number, is the range gate number, is the height represented by the first range gate, is the backscatter coefficient of the first range gate, is the backscattered power signal energy of the first range gate, Represents the product value of the lidar parameters, is the correction factor for the first range gate, is the initial atmospheric transmittance, is the initial extinction coefficient for iteration, is the distance resolution, is the echo energy measured horizontally, is the height measured horizontally, is the laser radar ratio, For the The height represented by the range gate, For the The backscatter coefficient of the range gate, For the The backscattered power signal energy of the range gate, It is the atmospheric transmittance calculated by the previous range gate.

[0028] On the other hand, in the above-mentioned meteorological element inversion method provided by the present invention, the expression of the relationship between the backscattering coefficient and the raindrop spectrum, the raindrop diameter, and the backscattering efficiency factor of different wavelengths is:

[0029] ;

[0030] ;

[0031] in, is the backscattering coefficient corresponding to the first wavelength, is the backscattering coefficient corresponding to the second wavelength, is the raindrop diameter, is the number of raindrops per unit scale interval, for The number of raindrops within the raindrop diameter scale interval, is the raindrop spectrum distribution, is the backscattering efficiency factor of the first wavelength laser, is the backscattering efficiency factor of the second wavelength laser.

[0032] On the other hand, in the above-mentioned meteorological element inversion method provided by the present invention, the raindrop spectrum distribution information is obtained by using the following formula:

[0033] ;

[0034] in, is the average diameter of raindrops on the ground, is the raindrop number concentration parameter, is the raindrop diameter, is the distribution shape factor.

[0035] In order to solve the above technical problems, the present invention also provides a meteorological element inversion device, comprising:

[0036] An echo signal receiving module, used for receiving two sets of atmospheric echo signals of a Doppler laser radar using a dual-wavelength emission mechanism; the two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules;

[0037] A spectrum information acquisition module, used for performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information;

[0038] A backscattering coefficient calculation module, used to extract the peak values ​​of the two sets of coherent spectrum information as backscattering power signals, and calculate the backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signals;

[0039] The raindrop information inversion module is used to obtain the relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground, and combines the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factor of different wavelengths to invert the raindrop spectrum distribution information at different heights.

[0040] In order to solve the above technical problems, the present invention also provides a meteorological element inversion device, comprising:

[0041] Memory for storing computer programs;

[0042] A processor is used to implement the steps of the above-mentioned meteorological element inversion method when executing the computer program.

[0043] In order to solve the above technical problems, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned meteorological element inversion method are implemented.

[0044] It can be seen from the above technical scheme that the present invention provides a meteorological element inversion method, which includes: receiving two groups of atmospheric echo signals of a Doppler laser radar using a dual-wavelength emission mechanism; the two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules; performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information; extracting the peak values ​​of the two groups of coherent spectrum information as backscattering power signals, and calculating the backscattering coefficients of aerosols at different heights measured by two wavelengths according to the backscattering power signals; obtaining a relationship model between the ratio of the backscattering coefficients measured by the two wavelengths and the average diameter of raindrops on the ground, and combining the pre-established relationship between the backscattering coefficient and the raindrop spectrum, the raindrop diameter, and the backscattering efficiency factor of different wavelengths to invert the raindrop spectrum distribution information at different heights.

[0045] The beneficial effect of the present invention lies in that the above-mentioned meteorological element inversion method provided by the present invention adopts Doppler laser radar to obtain atmospheric echo signals, which has the advantages of higher temporal and spatial resolution, small size and low cost, and the Doppler laser radar adopted by the present invention has a dual-wavelength emission mechanism, which can utilize the different water absorption characteristics of different wavelengths to measure the optical properties of aerosols, obtain the backscattering coefficients of aerosols measured at two wavelengths, and obtain the relationship model between the ratio of the backscattering coefficients measured at the two wavelengths and the average diameter of ground raindrops. According to the relationship model and the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factors of different wavelengths, it is used for the inversion of raindrop spectrum distribution information of the laser radar in the later stage. In addition, the laser radar of the present invention can obtain the backscattering coefficients at different heights. Compared with traditional raindrop spectrum detection instruments, it can obtain raindrop distributions at different heights and realize meteorological element measurement at multiple heights.

[0046] In addition, the present invention also provides a corresponding meteorological element inversion device, a meteorological element inversion equipment and a computer-readable storage medium for the meteorological element inversion method, which have the same or corresponding technical features as the above-mentioned meteorological element inversion method and have the same effects as above. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A flow chart of a meteorological element inversion method provided by an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of the absorption characteristics of water molecules at different wavelengths provided by an embodiment of the present invention;

[0050] Figure 3 A schematic diagram of the structure of a Doppler laser radar provided in an embodiment of the present invention;

[0051] Figure 4 A schematic diagram of a fitting curve corresponding to a relationship model between the ratio of backscatter coefficients and the average diameter of raindrops on the ground provided in an embodiment of the present invention;

[0052] Figure 5 A schematic diagram of the structure of a meteorological element inversion device provided in an embodiment of the present invention;

[0053] Figure 6 A schematic diagram of the structure of a meteorological element inversion device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] 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.

[0055] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Figure 1 A flow chart of a meteorological element inversion method provided by an embodiment of the present invention, such as Figure 1 As shown, the method includes:

[0056] S101. Receive two sets of atmospheric echo signals from a Doppler laser radar using a dual-wavelength emission mechanism; the two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules.

[0057] It should be noted that the execution body of the meteorological element inversion method provided by the present invention can be a data processor in a Doppler laser radar. The data processor can include a balanced detector and a data acquisition analyzer. The Doppler laser radar of the present invention adopts a dual-wavelength emission mechanism, and the two wavelengths in the emission mechanism have different absorption characteristics for water molecules, that is, the first wavelength is strongly absorbed and the backscattering is weak, and the second wavelength is non-absorbent or weakly absorbed and the backscattering is strong.

[0058] The first wavelength may be λ1=1531.351 nm, and the second wavelength may be λ2=1531.829 nm. The Doppler laser radar of the present invention includes 1531.351 nm wavelength channel detection data and 1531.829 nm wavelength channel detection data. Figure 2 The following is a schematic diagram of the absorption characteristics of water molecules at different wavelengths provided by the embodiment of the present invention, such as Figure 2 As shown in the figure, 1531.351nm is strongly absorbed and 1531.829nm is weakly absorbed. In practical applications, 1531.351nm and 1531.829nm are both example wavelengths. 1531.351nm can be replaced by other wavelengths that have strong absorption characteristics for water, and 1531.829nm can be replaced by other wavelengths that have no absorption or weak absorption for water.

[0059] The above two groups of atmospheric echo signals can be obtained by two lasers with different wavelengths emitting lasers at intervals, frequency modulating and amplifying the lasers through an acousto-optic modulator and an amplifier, and then emitting them into the atmosphere and reflecting them back to an optical transceiver; wherein the laser emission direction is controlled by a servo controller. Figure 3 A schematic diagram of the structure of a Doppler laser radar provided in an embodiment of the present invention is shown in FIG. Figure 3 As shown, wavelength 1 laser and wavelength 2 laser emit lasers alternately, and the frequencies are and ,Right now is the laser emission center frequency corresponding to the first wavelength, is the center frequency of the laser emission corresponding to the second wavelength. The laser frequency is changed by acousto-optic modulation, and the frequencies are , ,in The frequency of the acoustic-optical modulation is shifted; the amplifier amplifies the optical signal and transmits it into the atmosphere through an optical transceiver (such as a telescope). The direction of the laser emission can be controlled by a servo controller, and the atmospheric echo signal is received by a telescope. The balanced detector can receive two sets of atmospheric echo signals of the Doppler laser radar using a dual-wavelength emission mechanism.

[0060] S102, performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information.

[0061] In implementation, Figure 3 As shown, a balanced detector can be used to perform coherent frequency detection on two groups of atmospheric echo signals. After the optical signals are converted into electrical signals and collected and divided into range gates, fast Fourier transform (FFT) is performed to obtain two groups of coherent spectrum information.

[0062] S103, extracting peak values ​​of two sets of coherent spectrum information as backscattering power signals, and calculating backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signals.

[0063] In implementation, Figure 3 As shown, the data acquisition analyzer can be used to extract the peak values ​​of two sets of coherent spectrum information as backscattering power signals, and the backscattering coefficients of aerosols at different heights measured at two wavelengths can be calculated through the backscattering power signals.

[0064] S104, obtaining a relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground, and combining the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factors of different wavelengths to invert the raindrop spectrum distribution information at different heights.

[0065] It should be noted that the relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground can be obtained by cumulative correction of the actual measured values ​​of the raindrop spectrometer and the laser radar. The raindrop spectrum is the curve of the change of raindrop concentration with the size of raindrops. The backscattering efficiency factor is the ratio of the backscattering cross section of the particle to the geometric cross section of the particle, which reflects the efficiency of the particle in scattering the incident light to the back direction (i.e., the direction opposite to the direction of the incident light). The larger the backscattering efficiency factor, the higher the proportion of the particle scattering the incident light to the back direction, that is, the stronger the backscattering ability. This is very important for laser radar detection, because laser radar usually obtains target information by receiving the backscattered light of the target object. The present invention can use the data acquisition analyzer to calculate the raindrop spectrum distribution information at different heights based on the relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground, and the pre-established relationship between the backscattering coefficient and the raindrop spectrum, the raindrop diameter, and the backscattering efficiency factors of different wavelengths.

[0066] In the above-mentioned meteorological element inversion method provided by the embodiment of the present invention, a Doppler laser radar is used to obtain an atmospheric echo signal, which has the advantages of higher temporal and spatial resolution, small size and low cost. The Doppler laser radar used in the present invention has a dual-wavelength emission mechanism, and can use the different water absorption characteristics of different wavelengths to measure the optical properties of aerosols, obtain the backscattering coefficients of the aerosols measured at two wavelengths, and obtain a relationship model between the ratio of the backscattering coefficients measured at the two wavelengths and the average diameter of ground raindrops. According to the relationship model and the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factors of different wavelengths, it is used for the inversion of raindrop spectrum distribution information of the laser radar in the later stage. In addition, the laser radar of the present invention can obtain backscattering coefficients at different heights. Compared with traditional raindrop spectrum detection instruments, it can obtain raindrop distributions at different heights and realize multi-height meteorological element measurement.

[0067] Furthermore, in specific implementation, the above-mentioned meteorological element inversion method provided in the embodiment of the present invention may also include: calculating the radial component of the wind speed based on the Doppler frequency shift and wavelength corresponding to the two groups of atmospheric echo signals; and inverting the wind speed and direction information based on the radial component of the wind speed.

[0068] It should be noted that Doppler lidar wind measurement is achieved by measuring the Doppler frequency shift of laser radiation backscattered by particles in the atmosphere (dust, water droplets in clouds and fog, polluted aerosols, salt crystals, biomass burning aerosols, etc.). The radial wind speed can be further inverted into wind speed and direction data.

[0069] In practice, the present invention can measure wind speed and direction while measuring aerosol optical properties. Specifically, the radial component of wind speed can be calculated by analyzing Doppler frequency shift, and then information such as wind speed and wind direction can be inverted.

[0070] Radial wind speed With Doppler shift The relationship can be expressed by the following formula:

[0071] ;

[0072] in, for The corresponding frequency shift is caused by the movement of atmospheric aerosol particles.

[0073] Similarly, radial wind speed With Doppler shift The relationship can be expressed by the following formula:

[0074] ;

[0075] in, for The corresponding frequency shift is caused by the movement of atmospheric aerosol particles.

[0076] The radial wind speed is only the component speed of the wind speed on the laser beam. By measuring multiple radial velocities, the true wind speed can be inverted.

[0077] Further, in the specific implementation, in the above-mentioned meteorological element inversion method provided in the embodiment of the present invention, step S102 performs coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information, which may specifically include: performing relevant frequency detection on the two groups of atmospheric echo signals, and the frequencies of the two groups of atmospheric echo signals obtained by detection are respectively and ; Convert the two groups of atmospheric echo signals into electrical signals, perform fast Fourier transform after the electrical signals are collected and divided into range gates, and obtain two groups of related spectrum information.

[0078] In implementation, the lidar emits laser, and through the data acquisition system, the entire measurement distance can be divided into multiple distance areas, that is, the acquisition is divided into multiple distance gates.

[0079] Further, in a specific implementation, in the above-mentioned meteorological element inversion method provided in an embodiment of the present invention, step S103 calculates the backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signal, which may specifically include: for each wavelength, using the initial extinction coefficient of the horizontal measurement and the backscattering power signal energy of the first range gate to obtain the backscattering coefficient of the first range gate; according to the backscattering coefficient of the first range gate, calculating the extinction coefficient of the first range gate; using the extinction coefficient of the first range gate to iterate to the second range gate, combining the backscattering power signal energy of the second range gate, to obtain the backscattering coefficient of the second range gate; re-executing the calculation step of the extinction coefficient and iterating to the next range gate until the backscattering coefficients of all range gates are obtained.

[0080] In specific implementation, the backscatter coefficient of each range gate can be obtained by using the following formula:

[0081] ;

[0082] ;

[0083] ;

[0084] ;

[0085] ;

[0086] in, is the wavelength number, is the range gate number, is the height represented by the first range gate, is the backscatter coefficient of the first range gate, is the backscattered power signal energy of the first range gate, Represents the product value of the lidar parameters, is the correction factor for the first range gate, is the initial atmospheric transmittance, is the initial extinction coefficient for iteration, is the distance resolution, is the echo energy measured horizontally, is the height measured horizontally, is the laser radar ratio (can be set to 30), For the The height represented by the range gate, For the The backscatter coefficient of the range gate, For the The backscattered power signal energy of the range gate, It is the atmospheric transmittance calculated by the previous range gate.

[0087] In practice, the backscatter coefficient can be calculated by an iterative method, and the peaks of the two sets of spectra are extracted as the laser radar backscatter power signals P1 and P2, which are used to calculate the backscatter coefficients of the two wavelengths respectively. and , the calculation method is the same.

[0088] by Taking this as an example, the lidar signal can be expressed as:

[0089] ;

[0090] in, The laser radar with wavelength λ1 receives the height The energy of the atmospheric backscatter echo signal at Represents the product of all parameters such as the emission energy of the λ1 wavelength laser radar, radar parameters, etc. is the correction factor corresponding to the wavelength λ1, is the atmospheric backscattering coefficient corresponding to the wavelength λ1, is the atmospheric extinction coefficient of the λ1 wavelength laser.

[0091] The formula for the lidar signal of the first range gate is:

[0092] ;

[0093] in, Indicates the height represented by the first range gate, represents the backscatter coefficient of the first range gate at wavelength λ1, Represents the echo signal energy of the first range gate, Represents the correction factor of the first range gate. The first 1 represents the wavelength number, and the second 1 represents the range gate number.

[0094] ;

[0095] in, is the initial atmospheric transmittance of the λ1 wavelength laser, is the distance resolution, is the initial extinction coefficient corresponding to the wavelength λ1, It can be obtained through horizontal measurement. The servo-controlled radar performs horizontal measurement. Under the condition of uniform atmosphere, the aerosol concentration in the short horizontal range is basically the same. The slope of the following formula is fitted to get half of the extinction coefficient of the horizontal atmosphere, which is used as the initial extinction coefficient of the iteration:

[0096] ;

[0097] in, Indicates the height measured horizontally, Indicates the echo energy measured horizontally at wavelength λ1.

[0098] Correction Factor is calculated as the fitted line minus Then do the e index calculation. The fitting straight line here refers to The straight line obtained by linear fitting the above formula.

[0099] , and then solve ,in is the LiDAR ratio, which can be set to 30. It refers to the backscattering coefficient of the first range gate of the λ1 wavelength, which is the extinction coefficient of the first range gate of the λ1 wavelength divided by the lidar ratio. The extinction coefficient of the first range gate is replaced by the initial extinction coefficient of the horizontal measurement.

[0100] Next, we can infer The backscatter coefficient calculations for other heights can be expressed as:

[0101] ;

[0102] in, Atmospheric transmittance calculated for the previous range gate.

[0103] Calculated After that, it is available The extinction coefficient of this range gate is calculated to iterate to the next range gate.

[0104] Similarly, Taking this as an example, the lidar signal can be expressed as:

[0105] ;

[0106] in, The height received by the λ2 wavelength laser radar The energy of the atmospheric backscatter echo signal at Represents the product of all parameters such as the emission energy of the λ2 wavelength laser radar, radar parameters, etc. is the correction factor corresponding to the wavelength λ2, is the atmospheric backscattering coefficient corresponding to the wavelength λ2, is the atmospheric extinction coefficient of λ2 wavelength laser.

[0107] The formula for the lidar signal of the first range gate is:

[0108] ;

[0109] in, represents the backscatter coefficient of the first range gate at wavelength λ2, Represents the echo signal energy of the first range gate, Represents the correction factor of the first range gate. The first 2 represents the wavelength number, and the second 1 represents the range gate number.

[0110] ;

[0111] in, is the initial atmospheric transmittance of the λ2 wavelength laser, is the initial extinction coefficient corresponding to the wavelength λ2, It can be obtained through horizontal measurement. The servo-controlled radar performs horizontal measurement. Under the condition of uniform atmosphere, the aerosol concentration in the short horizontal range is basically the same. The slope of the following formula is fitted to get half of the extinction coefficient of the horizontal atmosphere, which is used as the initial extinction coefficient of the iteration:

[0112] ;

[0113] in, Indicates the height measured horizontally, Indicates the echo energy measured horizontally at the λ2 wavelength.

[0114] Correction Factor is calculated as the fitted line minus Then do the e index calculation. The fitting straight line here refers to The straight line obtained by linear fitting the above formula.

[0115] , and then solve ,in is the LiDAR ratio, which can be set to 30. It refers to the backscattering coefficient of the first range gate of the λ2 wavelength, which is the extinction coefficient of the first range gate of the λ2 wavelength divided by the lidar ratio. The extinction coefficient of the first range gate is replaced by the initial extinction coefficient of the horizontal measurement.

[0116] Next, we can infer The backscatter coefficient calculations for other heights can be expressed as:

[0117] ;

[0118] in, Atmospheric transmittance calculated for the previous range gate.

[0119] Calculated After that, it is available The extinction coefficient of this range gate is calculated to iterate to the next range gate.

[0120] Furthermore, in a specific implementation, in the above-mentioned meteorological element inversion method provided in an embodiment of the present invention, the expression for the relationship between the backscattering coefficient and the raindrop spectrum, the raindrop diameter, and the backscattering efficiency factor of different wavelengths is:

[0121] ;

[0122] ;

[0123] in, is the backscattering coefficient corresponding to the wavelength λ1, is the backscattering coefficient corresponding to the wavelength λ2, is the raindrop diameter, is the number of raindrops per unit scale interval, for The number of raindrops within the raindrop diameter scale interval, is the raindrop spectrum distribution, is the backscattering efficiency factor of the λ1 wavelength laser, is the backscattering efficiency factor of the λ2 wavelength laser.

[0124] It should be noted that the above formula is related to the size distribution of raindrops and is used to illustrate that the backscattering coefficient is related to the raindrop size. The backscattering coefficients at different heights can invert the raindrop sizes at different heights.

[0125] Since λ1=1531.398nm shows strong absorption to water droplets, λ2=1531.926nm shows weak absorption to water droplets, and the extinction of the two wavelengths to water droplets is close, the difference in the absorption characteristics of the two wavelengths to water droplets leads to the backscattering efficiency factor of the laser with wavelengths of λ1 and λ2. and Different, as the raindrop size increase, Gradually decreasing, Basically unchanged.

[0126] The ratio of the backscattering coefficients of the λ1 and λ2 wavelength lasers is: That is, the ratio of the backscatter coefficients at different heights can be: .

[0127] Ratio of backscatter coefficients and the average diameter of raindrops The relationship model can be corrected by accumulating the actual measurements of the raindrop spectrometer and lidar.

[0128] LiDAR acquisition , ground height for , while the raindrop spectrum obtains the average diameter of raindrops on the ground data, The value range is 0.05~1mm, and The relative relationship of is used for polynomial fitting:

[0129] ;

[0130] in, The diameter of the raindrop spectrum is The ground height is The ratio of the backscattering coefficients is are the polynomial coefficients, .

[0131] According to the polynomial fitting results, the ratio of the backscattering coefficients is obtained and the average diameter of raindrops The fitting curve corresponding to the relationship model is Find the average diameter of raindrops database. Figure 4A schematic diagram of a fitting curve corresponding to the relationship model between the ratio of backscatter coefficients and the average diameter of raindrops on the ground provided in an embodiment of the present invention.

[0132] Furthermore, in a specific implementation, in the above-mentioned meteorological element inversion method provided in an embodiment of the present invention, the following formula is used to obtain the raindrop spectrum distribution information:

[0133] ;

[0134] in, is the raindrop number concentration parameter, is the raindrop diameter, The value range is 0.05~1mm, is the distribution shape factor, take , By quickly searching the above database, the raindrop spectrum distribution can be finally obtained, from which the observation of multiple meteorological elements such as wind field at different altitudes, aerosol optical properties and raindrop spectrum can be realized.

[0135] In the above embodiments, the meteorological element inversion method is described in detail, and the present invention also provides embodiments corresponding to the meteorological element inversion device and the meteorological element inversion equipment. It should be noted that the present invention describes the embodiments of the device part from two perspectives, one is based on the functional module perspective, and the other is based on the hardware perspective.

[0136] Figure 5 The schematic diagram of the structure of the meteorological element inversion device provided by the embodiment of the present invention is shown in FIG. Figure 5 As shown, the device comprises:

[0137] The echo signal receiving module 10 is used to receive two sets of atmospheric echo signals of a Doppler laser radar using a dual-wavelength emission mechanism; the two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules;

[0138] The spectrum information acquisition module 11 is used to perform coherent frequency detection and fast Fourier transform on two groups of atmospheric echo signals to obtain two groups of coherent spectrum information;

[0139] A backscattering coefficient calculation module 12 is used to extract the peak values ​​of the two sets of coherent spectrum information as backscattering power signals, and calculate the backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signals;

[0140] The raindrop information inversion module 13 is used to obtain the relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground, and to invert the raindrop spectrum distribution information at different heights by combining the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factors of different wavelengths.

[0141] In the above-mentioned meteorological element inversion device provided by the embodiment of the present invention, a Doppler laser radar is used to obtain the atmospheric echo signal, which has the advantages of higher temporal and spatial resolution, small size and low cost. The Doppler laser radar used in the present invention has a dual-wavelength emission mechanism, and can use the different water absorption characteristics of different wavelengths to measure the optical properties of aerosols, obtain the backscattering coefficients of the aerosols measured at two wavelengths, and obtain a relationship model between the ratio of the backscattering coefficients measured at the two wavelengths and the average diameter of raindrops on the ground. According to the relationship model and the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factors of different wavelengths, it is used for the inversion of raindrop spectrum distribution information of the laser radar in the later stage; in addition, the laser radar of the present invention can obtain backscattering coefficients at different heights. Compared with traditional raindrop spectrum detection instruments, it can obtain raindrop distributions at different heights and realize meteorological element measurement at multiple heights.

[0142] It should be noted that the echo signal receiving module 10 and the spectrum information acquisition module 11 can be integrated into the balanced detector of the Doppler laser radar, and the backscatter coefficient calculation module 12 and the raindrop information inversion module 13 can be integrated into the data acquisition analyzer of the Doppler laser radar.

[0143] Since the embodiments of the device part correspond to the embodiments of the method part, the embodiments of the device part refer to the description of the embodiments of the method part, which will not be described here. And it has the same beneficial effects as the above-mentioned meteorological element inversion method.

[0144] Figure 6 The schematic diagram of the structure of the meteorological element inversion device provided in the embodiment of the present invention. This embodiment is based on the hardware perspective, such as Figure 6 As shown, the meteorological element inversion equipment includes:

[0145] A memory 20, used for storing computer programs;

[0146] The processor 21 is used to implement the steps of the meteorological element inversion method mentioned in the above embodiment when executing the computer program.

[0147] Among them, the processor 21 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 21 can be implemented in at least one hardware form of a digital signal processor (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor 21 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU; the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 21 may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 21 may also include an artificial intelligence (AI) processor, which is used to process computing operations related to machine learning.

[0148] The memory 20 may include one or more computer-readable storage media, which may be non-transitory. The memory 20 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In this embodiment, the memory 20 is at least used to store the following computer program 201, wherein, after the computer program is loaded and executed by the processor 21, the relevant steps of the meteorological element inversion method disclosed in any of the aforementioned embodiments can be implemented. In addition, the resources stored in the memory 20 may also include an operating system 202 and data 203, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system 202 may include Windows, Unix, Linux, etc. The data 203 may include, but is not limited to, the data involved in the above-mentioned meteorological element inversion method, etc.

[0149] In some embodiments, the meteorological element inversion device may further include a display screen 22, an input / output interface 23, a communication interface 24, a power supply 25, and a communication bus 26. Those skilled in the art will appreciate that Figure 6 The structure shown in the figure does not constitute a limitation on the meteorological element inversion device, and may include more or fewer components than shown in the figure. The meteorological element inversion device provided by the embodiment of the present invention includes a memory and a processor. When the processor executes the program stored in the memory, it can implement the meteorological element inversion method mentioned above, and the effect is the same as above.

[0150] Finally, the present invention also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps recorded in the above method embodiment are implemented.

[0151] It is understandable that if the method in the above embodiment is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium to execute all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code. The computer-readable storage medium provided by the present invention can implement the above-mentioned meteorological element inversion method, and the effect is the same as above.

[0152] Finally, the present invention also provides an embodiment corresponding to a computer program product. The computer program product includes a computer program / instruction, and when the computer program / instruction is executed by a processor, the steps recorded in the above-mentioned meteorological element inversion method embodiment are implemented. The computer program product provided by the present invention can implement the above-mentioned meteorological element inversion method, and the effect is the same as above.

[0153] It should also be noted that, in this specification, 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 "comprise", "include" 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, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0154] The above is a detailed introduction to the meteorological element inversion method, device, equipment and medium provided by the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A meteorological element inversion method, characterized in that: include: Receive two sets of atmospheric echo signals from Doppler laser radar using a dual-wavelength emission mechanism; The two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules; Performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information; Extracting peak values ​​of the two sets of coherent spectrum information as backscattering power signals, and calculating backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signals; Obtain the relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of raindrops on the ground, and combine the pre-established relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factors of different wavelengths to invert the raindrop spectrum distribution information at different heights; Among them, the expression of the relationship between the backscattering coefficient and the raindrop spectrum, raindrop diameter, and backscattering efficiency factor of different wavelengths is: ； ； in, is the backscattering coefficient corresponding to the first wavelength, is the backscattering coefficient corresponding to the second wavelength, is the raindrop diameter, is the number of raindrops per unit scale interval, for The number of raindrops within the raindrop diameter scale interval, is the raindrop spectrum distribution, is the backscattering efficiency factor of the first wavelength laser, is the backscattering efficiency factor of the second wavelength laser; Get the ratio of backscatter coefficients , ground height for , and obtain the average diameter of raindrops on the ground , and The relative relationship of is used for polynomial fitting: ； in, The diameter of the raindrop spectrum at the ground height is The ratio of the backscattering coefficients is are the polynomial coefficients, ; According to the polynomial fitting result, a fitting curve corresponding to the relationship model between the ratio of the backscattering coefficient and the average diameter of the raindrops on the ground is obtained; the fitting curve is used as a database for searching the average diameter of the raindrops on the ground; The average diameter of raindrops on the ground corresponding to the ratio of backscatter coefficients is found by using the database. ; The raindrop spectrum distribution information is obtained using the following formula: ； in, is the average diameter of raindrops on the ground, is the raindrop number concentration parameter, is the raindrop diameter, is the distribution shape factor.

2. The meteorological element inversion method according to claim 1, characterized in that: Also includes: The radial component of the wind speed is calculated according to the Doppler frequency shift and wavelength corresponding to the two groups of atmospheric echo signals; The wind speed and direction information is inverted according to the radial component of the wind speed.

3. The meteorological element inversion method according to claim 1, characterized in that: Performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information, including: The two groups of atmospheric echo signals are subjected to relevant frequency detection, and the frequencies of the two groups of atmospheric echo signals obtained by detection are respectively and ;in, is the laser emission center frequency corresponding to the first wavelength; is the laser emission center frequency corresponding to the second wavelength; Frequency shift for acousto-optic modulation; for The corresponding frequency shift caused by the movement of atmospheric aerosol particles; for The corresponding frequency shift caused by the movement of atmospheric aerosol particles; The two groups of atmospheric echo signals are converted into electrical signals, and after the electrical signals are collected and divided into range gates, fast Fourier transform is performed to obtain two groups of related frequency spectrum information.

4. The meteorological element inversion method according to claim 1, characterized in that: The backscattering coefficients of aerosols at different heights measured at two wavelengths are calculated according to the backscattering power signal, including: For each wavelength, the backscatter coefficient of the first range gate is obtained by using the initial extinction coefficient of the horizontal measurement and the backscatter power signal energy of the first range gate; According to the backscattering coefficient of the first range gate, the extinction coefficient of the first range gate is calculated; Iterating the extinction coefficient of the first range gate into the second range gate, and combining the backscatter power signal energy of the second range gate to obtain the backscatter coefficient of the second range gate; The extinction coefficient is re-executed and the calculation step of the next range gate is iterated until the backscattering coefficients of all range gates are obtained.

5. The meteorological element inversion method according to claim 4, characterized in that: The backscatter coefficient of each range gate is obtained using the following formula: ； ； ； ； ； in, is the wavelength number, is the range gate number, is the height represented by the first range gate, is the backscatter coefficient of the first range gate, is the backscattered power signal energy of the first range gate, Represents the product value of the lidar parameters, is the correction factor for the first range gate, is the initial atmospheric transmittance, is the initial extinction coefficient for iteration, is the distance resolution, is the echo energy measured horizontally, is the height measured horizontally, is the laser radar ratio, For the The height represented by the range gate, For the The backscatter coefficient of the range gate, For the The backscattered power signal energy of the range gate, For the Atmospheric transmittance calculated using a range gate.

6. A meteorological element inversion device, characterized in that: include: An echo signal receiving module is used to receive two sets of atmospheric echo signals of a Doppler laser radar adopting a dual-wavelength emission mechanism; The two wavelengths in the dual-wavelength emission mechanism have different absorption characteristics for water molecules; A spectrum information acquisition module, used for performing coherent frequency detection and fast Fourier transform on the two groups of atmospheric echo signals to obtain two groups of coherent spectrum information; A backscattering coefficient calculation module, used to extract the peak values ​​of the two sets of coherent spectrum information as backscattering power signals, and calculate the backscattering coefficients of aerosols at different heights measured at two wavelengths according to the backscattering power signals; The raindrop information inversion module is used to obtain the relationship model between the ratio of the backscattering coefficients measured at two wavelengths and the average diameter of the raindrops on the ground, and to invert the raindrop spectrum distribution information at different heights by combining the pre-established relationship between the backscattering coefficient and the raindrop spectrum, the raindrop diameter, and the backscattering efficiency factor of different wavelengths; the expression for the relationship between the backscattering coefficient and the raindrop spectrum, the raindrop diameter, and the backscattering efficiency factor of different wavelengths is: ； ； in, is the backscattering coefficient corresponding to the first wavelength, is the backscattering coefficient corresponding to the second wavelength, is the raindrop diameter, is the number of raindrops per unit scale interval, for The number of raindrops within the raindrop diameter scale interval, is the raindrop spectrum distribution, is the backscattering efficiency factor of the first wavelength laser, is the backscattering efficiency factor of the second wavelength laser; Get the ratio of backscatter coefficients , ground height for , and obtain the average diameter of raindrops on the ground , and The relative relationship of is used for polynomial fitting: ； in, The diameter of the raindrop spectrum at the ground height is The ratio of the backscattering coefficients is are the polynomial coefficients, ; According to the polynomial fitting results, the ratio of the backscattering coefficients is obtained and the average diameter of raindrops on the ground The fitting curve corresponding to the relationship model of Find the average diameter of raindrops on the ground database; By searching the database, the average diameter of raindrops on the ground is obtained. ; The raindrop spectrum distribution information is obtained using the following formula: ； in, is the average diameter of raindrops on the ground, is the raindrop number concentration parameter, is the raindrop diameter, is the distribution shape factor.

7. A meteorological element inversion device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the meteorological element inversion method as described in any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the meteorological element inversion method according to any one of claims 1 to 5 are implemented.

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