关键词: 激光雷达, 边界层高度, 小波变换法, Haar函数, Morlet函数, MexicanHat函数

Abstract:

When applying wavelet transformation method in the retrieval of the boundary layer height by using lidar backscatter signals， the different selection of wavelet generating function may get different results．Therefore，the idealized lidar signal profiles during the daytime and nighttime have been built to explore which wavelet generating function will get the best performance．In this study，Haar wavelet covariance transformation has been used for the profiles of lidar backscatter signal，and Morlet and Mexican Hat wavelet transformation have been utilized for the gradient profiles of lidar backscatter signal，respectively．The results showed that the Haar function and the Mexican Hat function should be used as wavelet generating functions:the Haar function is more accurate and the Mexican Hat function is more stable． Furthermore，the changed wavelet dilation of the wavelet generating function also has been researched in order to test the sensitivity of the three different wavelet transformation methods to the wavelet dilation． The result show that whatever the idealized profile or the profile in which disturbance was added，the larger wavelet dilation can get a more stable and accurate diurnal boundary layer height and nocturnal mixing layer height．

Key words: lidar, boundary layer height, wavelet transformation, Haar function, Morlet function, Mexican Hat function