Application of Kalman Filtering and Wavelet Transform in DOAS

Differential optical absorption spectroscopy (DOAS) has become a widely used method to measure trace gases in the atmosphere. Concentration of trace gases is retrieved by fitting reference spectra to the atmospheric absorption spectra. There were large errors in retrieved results, when absorption structures were heavily overlapped and the noises were high. The novel method of combining Wavelet transform and Kalman filtering was developed and applied to DOAS data processing. The experiment results show the method can effectively correct overlapped spectra and reduce the noise. The novel method improves the accuracy of the DOAS system