Detection of the planetary boundary layer height by employing the Scheimpflug lidar technique and the covariance wavelet transform method

A portable Scheimpflug lidar system has been employed for atmospheric boundary layer studies. Atmospheric backscattering signals were continuously recorded from 21 August to 28 August 2018. The covariance wavelet transform (CWT) method was utilized to identify the maximum gradient of recorded lidar curves as the planetary boundary layer (PBL) height. As the directly retrieved PBL height could be underestimated or overestimated due to the presence of residual layers and thin clouds, localized atmospheric turbulence, aerosol stratification, etc., a CWT-based quality-control algorithm has also been developed to improve the reliability of the PBL height retrieval. The temporal distribution of the final PBL height has shown a clear diurnal variation as the ambient temperature changed due to the increasing and decreasing of surface heating during a one-week continuous measurement campaign. The promising results have shown great potential in employing the Scheimpflug lidar technique and the CWT-based method in the determination of the PBL height.