A ground-to-ground lidar for aerosol detection

Abstract

The invention discloses an earth laser radar for aerosol detection and relates to the field of laser atmospheric remote sensing. The ground-based laser radar includes a double-line-of-view laser radarand an inversion processing module. The double-line-of-view laser radar includes a first laser radar and a second laser radar. The first laser radar includes a first transmitting system, a first echoreceiving system, and a first detection acquisition processing system. The second laser radar includes a second transmitting system, a second echo receiving system, and a second detection acquisitionprocessing system. The first laser radar vertically downward observes the ground to obtain a laser radar echo profile. The second laser radar observes the ground by an inclination angle of [theta] toobtain the laser radar echo profile. The data detected by the first and second laser radars is sent to a data processing and inversion module 2 and then an extinction coefficient profile and a laserradar ratio profile can be obtained by inversion. The earth laser radar achieves an aerosol optical property detection accuracy of better than 20%, and also solves the defects of a Raman laser radar and a high-spectral resolution laser radar.

Description

technical field [0001] The invention relates to the field of laser atmospheric remote sensing, in particular to a ground laser radar for aerosol detection. Background technique [0002] The main lidar technologies currently used for aerosol profile detection are backscatter lidar technology, Raman scattering lidar technology, and hyperspectral resolution lidar technology. In order to realize the detection of aerosol particle size distribution, it is also necessary to adopt multi-wavelength (generally 1064nm, 532nm, 355nm) detection methods. [0003] Among the above methods, the backscatter lidar has the lowest comprehensive requirements for the laser (usually the line width of the order of 10-100pm, the energy of the order of uJ-100mJ), and the lowest comprehensive requirements for the receiving optical system, and its backscattering cross-section It is the largest, can work at any wavelength, and can be used in the development of airborne and spaceborne lidars. It is curre...

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Problems solved by technology

[0007] 1. The requirements for lasers are extremely high, especially the requirements for line width and wavelength stability control are extremely high, which requires special laser design technology, and the development cost, development cycle, development difficulty and work risk are multiplied;

[0008] 2. The requirements for relay optics are extremely high. In order to achieve high spectral resolution filtering, special optical elements with high cost, high difficulty, high risk, low adaptability, and low transmittance must be used, resulting in low feasibility;

[0009] 3. The operating wavelength is limited. For example, the atomic filter system can only be used for 532nm. Although the FP etalon can be used for multiple wavelengths, the transmittance at 355nm is extremely low, and the molecular scattering at 1064nm is extremely weak and it is difficult to use hyperspectral resolution.

In the process of aerosol detection, the more wavelengths, the higher the accuracy of particle size inversion, so this technology is not conducive to higher precision particle size inversion

[0010] To sum up, the first type of backscattering lidar has the lowest cost and difficulty, and is easy to implement, but the accuracy can only reach 30% to 50%; the second type of Raman scattering lidar has higher cost and difficulty, and its accuracy can reach 20%. %, is easier to implement, but cannot be used for space-borne earth observation; the third hyperspectral resolution laser radar can reach 20% accuracy, and can also be used for space-borne, but its development cost and development difficulty are doubled compared with the first two increase, difficult to achieve

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