A Water Vapor Concentration Measurement Correction Method Based on Tunable Laser Absorption Spectroscopy

Abstract

The invention discloses a water vapor concentration measurement correction method based on tunable laser absorption spectrometry, wherein the method includes the following steps: converting a measuredAD value into the water vapor concentration C according to an AD value-water vapor concentration fitting function C=k1(AD) with a laser water vapor concentration measurement device; measuring the environment temperature T and the environment total pressure P through temperature and pressure sensors, and carrying out temperature correction and total pressure correction on the water vapor concentration C obtained from calculation, to obtain a water vapor concentration correction value C1; obtaining a to-be-detected water vapor concentration range [0, CE] according to the temperature T and knownsaturated water vapor concentrations CE at different temperatures, and setting the water vapor concentration value as C0=(0+CE) / 2= CE / 2; comparing the water vapor concentration correction value C1 with the water vapor concentration set value C0; and by a iterative algorithm, making the corrected water vapor concentration value be C2, and thus completing the whole correction process. The correction method provided by the invention can eliminate the influence of changes of the temperature, total pressure and water vapor partial pressure on the tunable laser absorption spectrometry measurement of the water vapor concentration, and improves the accuracy of water vapor concentration measurement of air-sea fluxes.

Description

technical field [0001] The invention relates to the technical field of water vapor concentration measurement, in particular to a method for measuring and correcting water vapor concentration of sea-air interface flux based on laser absorption spectroscopy technology. Background technique [0002] The air-sea interface flux is an important parameter to describe the interaction between the atmospheric boundary layer and the upper surface of the ocean. The related research on the flux at the air-sea interface is very important for the understanding of the energy and material exchange at the air-sea interface, the coupling effect of the air-sea, the dynamic process of the ocean and the atmosphere at different scales, the numerical simulation of the ocean and the atmosphere, weather forecasting and climate dynamics research. is of great significance. [0003] Water vapor flux is the amount of water vapor material exchange between the ocean and the atmosphere. The water vapor flu...

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Problems solved by technology

At present, the water vapor concentration analyzer used in the air-sea flux observation adopts non-dispersive infrared spectroscopy detection technology (NDIR). In the actual application process, the non-dispersive infrared spectroscopy detection technology mainly has the following two problems: The detection technology uses a broadband light source, the stability of the light source is not high, there are absorption lines of other gases within the range of the target water vapor absorption line, and there is spectral line interference, which will affect the accurate measurement of water vapor concentration; second, non-dispersive infrared spectrum detection The technology adopts the infrared spectrum direct absorption method, and it is difficult to eliminate the influence of the infrared light transmittance change caused by the pollution of the window and the fluctuation of the broadband light source.

For the air-sea flux water vapor concentration analyzer, the water vapor concentration in the natural environment can vary from hundreds of ppm to hundreds of thousands of ppm. The amplitude of the harmonic signal detected by the TDLAS system affects

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