Abstract: In order to realize non-contact high-resolution and high-precision measurement of small-scale wind field, and make up for the measurement blind area of pulse coherent wind lidar in the close wind field, a high power CW fiber laser with working wavelength of 1550 nm, which is safe for human eyes, was selected as the light source of lidar, and then based on the principle of laser coherent wind measurement, the wind speed detection at different positions in the wind field was realized by changing the focusing position of continuous wave laser. The local oscillator power of the current system was optimized to improve the signal-to-noise ratio of the system, and by optimizing the effective spectral centroid algorithm, the data of multiple velocity components in the measured interval of continuous wave were processed so as to improve the accuracy of data inversion. The comparative experiment between the lidar system and the ultrasonic anemometer was carried out, the correlation of wind speed data of the two systems is 0.98 and the standard deviation is 0.16 m·s−1. Then the long-term wind speed observation experiment was carried out by using the lidar system, and several groups of data with different aerosol content under different weather were selected for analysis. Meanwhile, the change of wind speed in the wind field near the ground and near buildings was explored. The experimental results of local wind speed observation show that the wind speed measurement range of the system is 0.3∼18 m·s−1, and the wind field measurement position is 2∼30 m, which can realize the continuous measurement of wind speed gradient.

Key words: continuous wave laser, wind lidar, coherence detection, varifocal