Two-component wind fields from single scanning aerosol lidar

This paper will present recent research results on the development and testing of two motion estimation algorithms as applied to image sequences from a single ground-based scanning elastic backscatter aerosol lidar. The resulting two-component vector flow fields usually cover areas from 5 to 15 square kilometers and are updated every 10 to 20 seconds. The spacing of the vectors is every 10 m, but the spatial resolution of the vector flow fields is related to the availability and scale of the aerosol features in the images (in addition to the algorithm parameters). For wavelet-based optical flow, we have resolved dramatic changes in velocity resulting from intense surface layer vortices that occur in daytime weak-wind convective conditions over land with abundant sources of aerosols. In addition to time-lapse visualizations of turbulent flow in the lower atmospheric boundary layer, time and space series comparisons with horizontal wind components from sonic anemometers and a Doppler lidar will be shown. The merit of this capability is the ability to provide two-component horizontal wind fields over horizontal areas from a single instrument. Two horizontal velocity components are needed for speed and direction. This capability may be useful for example in activities such as wind resource assessment (especially offshore) and very short term (seconds to minutes) wind prediction.