Method for measuring transmittance of whole atmosphere based on sodium beacon in specified direction

Abstract

The invention discloses a method for measuring transmittance of the whole atmosphere based on a sodium beacon specified direction. The method comprises the steps: S1, selecting a fixed star, and determining the atmospheric transmittance Ta in the direction of the fixed star; meanwhile, in an isoplanatic region of the selected fixed star, emitting laser with a set wavelength to excite sodium atomsin an atmospheric interlayer to generate resonance fluorescence scattering in the atmospheric interlayer so as to generate a sodium beacon; S2, obtaining an influence parameter beta of the sodium abundance on the brightness of the sodium beacon; S3, emitting laser in a target detection direction to excite the sodium beacon at the position; and S4, calculating to obtain the whole atmospheric transmittance T'a in the target detection direction. According to the method, the influence parameters of the sodium abundance on the brightness of the sodium beacon are calibrated by using the brightness of the known fixed star and the brightness of the excited sodium beacon, so that the transmittance of the whole atmosphere in other specified direction is obtained.

Description

technical field [0001] The invention relates to the field of atmospheric optical detection and atmospheric measurement, in particular to a method for measuring the transmittance of the whole layer of atmosphere based on the direction specified by the sodium beacon. Background technique [0002] Atmospheric transmittance is the extinction effect caused by the absorption of atmospheric molecules and the scattering of aerosols. The extinction effect will cause the energy attenuation of the laser in the direction of propagation. transmittance is affected. The whole-layer atmospheric transmittance can reflect atmospheric meteorological conditions and radiation transfer properties, and has important applications in the fields of environmental monitoring, atmospheric radiation, and space object detection. [0003] At present, there are three main methods of atmospheric transmittance: model calculation method, passive measurement method, and active measurement method based on lidar...

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Problems solved by technology

[0004] Among the above three methods, the model calculation method relies on the atmospheric model, which cannot reflect the real situation of the atmosphere at the measurement location in real time, accurately and truly

Although the solar / star radiometer method is simple and convenient, and measures the transmittance of the entire atmosphere, it is limited by the azimuth angle of the sun / star, and has high requirements for meteorological conditions, so it can only work under clear and cloudless conditions

Although the direct measurement method is not limited by the azimuth angle of the sun / star, it cannot obtain the transmittance data of the entire atmosphere, and the problem of obtaining the transmittance when the sky is thin and cloudy is still not solved

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