Measuring method of atmospheric water vapor molecule absorption coefficient profile

Abstract

The invention discloses a measuring method of an atmospheric water vapor molecule absorption coefficient profile. The method comprises the following steps: (1) measuring an atmospheric water vapor molecule density profile, an atmospheric temperature profile and near-ground atmospheric pressure, and calculating out an atmospheric pressure profile according to the near-ground atmospheric pressure; (2) according to the atmospheric water vapor molecule density profile, the atmospheric temperature profile and the atmospheric pressure profile, at a specified altitude, obtaining spectral line absorption strength and continuous absorption strength of each water vapor molecule absorption spectral line at a wave number v, and obtaining the total water vapor molecule absorption strength after summing the spectral line absorption strength and the continuous absorption strength; (3) obtaining an absorption coefficient of atmospheric water vapor molecule at the wave number v according to the measured atmospheric water vapor molecule density profile and the total atmospheric water vapor molecule absorption strength at the wave number v; and (4) repeating the steps (2) and (3), orderly calculating the atmospheric water vapor molecule absorption coefficient at each altitude, and thus obtaining the atmospheric water vapor molecule absorption coefficient profile. The method provided by the invention can measure the atmospheric water vapor molecule absorption coefficient profile in real time.

Description

technical field [0001] The invention relates to a measurement method, in particular to a method for measuring the absorption coefficient profile of atmospheric water vapor molecules. Background technique [0002] During the actual atmospheric transmission of the laser, due to the absorption of water vapor molecules in the atmosphere, the laser energy will be attenuated. For the laser with strong power, it will also produce a nonlinear thermal halo effect, resulting in the decline of the beam quality and the expansion of the far-field spot. Engineering applications of lasers. In order to evaluate the influence of atmospheric water vapor absorption on laser atmospheric transmission, it is necessary to measure the absorption coefficient profile of atmospheric water vapor molecules. In the near- and mid-infrared spectral region (1-12 μm), it is the main spectral interval for laser engineering applications. In this interval, water vapor molecules are the most important atmospher...

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Problems solved by technology

This method has the following disadvantages: the measurement method of the sounding balloon has poor real-time performance, and the measurement path cannot be controlled, which cannot meet the requirements for real-time measurement of the absorption coefficient profile of water vapor molecules on the laser transmission path

The disadvantages of this method are: 1) The measurement height is limited. Generally, the Raman lidar system is about 3km during the day and 6km at night, and there is a blind area (generally about hundreds of meters); 2) It cannot measure the atmospheric temperature profile , the resulting result is that the calculation accuracy of the atmospheric water vapor absorption coefficient is not high enough; 3) The development cost of the Raman lidar system is high, because the Raman signal backscattered by the atmosphere is weak, in order to obtain a sufficient signal-to-noise ratio, in addition to the need In addition to the high emission power of the laser, it also requires a large optical receiving aperture, generally not less than Φ500, so a system costs about several million yuan; 4) The operation and maintenance of the Raman lidar system is complicated, and it is not suitable for long-term field operation

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