Application of Wavelet Transform in Differential Absorption Spectrum Data Analysis

Differential optical absorption spectroscopy (DOAS) is a commonly used method to measure the concentration of trace gases in the atmosphere. On the basis of DOAS algorithm, the effect of polynomial smooth denoising, soft threshold and hard threshold wavelet denoising on the inversion accuracy of SO2 concentration were studied. The results show that three algorithms have good noise reduction ability. Wavelet denoising threshold value which was calculated based on the signal itself to estimate noise intensity, when the measured noise data relative to the difference is bigger, the inversion precision of wavelet transform with hard threshold is the highest, the measurement error is within 3.7%.