Wavelet-Based Optical Flow for Two-Component Wind Field Estimation from Single Aerosol Lidar Data

Abstract

motion estimation algorithm was applied to image sequences produced by a horizontally scanning elastic backscatter lidar. The algorithm, a wavelet-based optical flow estimator named Typhoon, produces dense two-component vector flow fields that correspond to the apparent motion of microscale aerosol features. To validate the efficacy of this approach for the remote measurement of wind fields in the lower atmosphere, an experiment was conducted in Chico, California, in 2013 and 2014. The flow fields, estimated every 17 s, were compared with measurements from an independent Doppler lidar. Time series of wind speed and direction, statistical assessment of the 10-min averages, and examples of wind fields are presented. The comparison of 10-min averages at 100 m AGL reveals excellent correlations between estimates from the Typhoon algorithm and measurements from the Doppler lidar. Power spectra and spectral transfer functions are computed to estimate the filtering effects of the algorithm in the spatial domain.