Effect of temperature on CO_2 absorption spectrum near 1432nm

摘要

As the most important greenhouse gas, CO_2 has caused a lot of climate change problems. Therefore, themeasurement of CO_2 is of great significance. Based on the tunable diode laser absorption spectroscopy (TDLAS), theeffect of temperature on the absorption spectrum of CO_2 was studied. A DFB laser with the center wavelength of 1430nm was selected. The absorption line of CO_2 near 1432 nm at different temperatures (293-373 K, interval 10K) wasmeasured by wavelength modulation spectroscopy (WMS). By comparing S-G filtering method, FFT filtering methodand P-F filtering method, the spectral data was preprocessed, and the optimal preprocessing method was determined. Themeasurement error caused by noise was reduced effectively, the second harmonic signal of CO_2 at different temperatureswas obtained, and the influence of temperature on the absorption spectrum of CO_2 was analyzed. The goodness of fit oftemperature and signal strength under different orders was evaluated. Finally, the second-order polynomial fitting waschosen as the optimal model of CO_2.The experimental results complement and improve the existing database to ensurethe accuracy of CO_2 inversion, which has an important reference significance for the measurement of CO_2 in practicalapplications.