Spatial resolution enhancement of coherent Doppler wind lidar using joint time-frequency analysis

Spatial resolution enhancement of a coherent detection Doppler wind lidar (CDWL) is generally achieved by reducing the pulse duration of the transmitted laser according to the basic lidar equation, inevitably, at sacrifice of other properties, such as the signal to noise ratio, maximum detection range and real time data processing. To solve this problem, a joint time-frequency analysis (JTFA) method is adopted in the CDWL. By comparing the performance of Cohen's class in analysis and wind retrieval simulation, the adaptive optimized kernel (AOK) is picked up as the best JTFA method in the CDWL. In experiment, wind profiles retrieved using the JTFA and the FFT are compared with the result simulated using the software ANSYS 18.0. Benefiting from the high spatial resolution of the JTFA method, the dynamic structure of wind shear in the gap of two tall buildings is detected clearly, which agrees well with the simulation.