Fig. 1. Schematic of wind measurement based on lidar echo correlation. (a) Measurement of aerosol inhomogeneity by lidar; (b) signal curves of lidar 1 at distance of L1 and lidar 2 at distance of L2

Fig. 2. Correlation coefficient R12 versus delay time Δt

Fig. 3. Principle of three-beam two-dimensional wind field inversion method. (a) Position and angle of three lidars; (b) schematic of wind velocity and direction inversion

Fig. 4. Correlation-based two-dimensional wind measurement lidar system. (a) Structural diagram; (b) physical map

Fig. 5. Positions of correlation-based two-dimensional wind measurement lidar system and wind tower

Fig. 6. Signal curves at distance of 450 m and signal temporal variations for three lidars. (a) Signal curve of lidar 1; (b) signal curve of lidar 2; (c) signal curve of lidar 3; (d) signal temporal variation of lidar 1; (e) signal temporal variation of lidar 2; (f) signal temporal variation of lidar 3

Fig. 7. Signal curves of lidar 2 at different distances. (a) 150 m; (b) 300 m; (c) 450 m; (d) 600 m; (e) 750 m; (f) 900 m; (g) 1050 m; (h) 1200 m; (i) 1350 m

Fig. 8. Measurement results of wind speed and direction by correlation-based two-dimensional wind measurement lidar system under different lidar angles. (a) Wind speed; (b) wind direction

Fig. 9. Correlation curves for different lengths of time sequences. (a) 500 s; (b) 300 s; (c) 200 s; (d) 100 s; (e) 50 s; (f) 20 s

Fig. 10. Curves of wind speed and direction measured by correlation-based two-dimensional wind measurement lidar system at specific time. (a) Wind speed; (b) wind direction

Fig. 11. Curves of 2700 s wind speed and direction at night and in daytime measured by correlation-based two-dimensional wind lidar measurement system at distance of 450 m. (a) Wind speed at night; (b) wind direction at night; (c) wind speed in daytime; (d) wind direction in daytime

Table 1. Main parameters of lidar