摘要
多普勒激光雷达在晴空大气风场探测中具有高精度和高时空分辨率的特点。中国气象局气象探测中心的车载非相干多普勒激光雷达基于高光谱技术,可以进行大气风廓线、水平风场和扇形风场的探测。2011年3月~4月,用该激光雷达在北京南郊观象台与L波段探空雷达进行了同步对比观测,得到50组可对比风廓线数据,平均有效探测高度为6038 m。在能见度较好的情况下,有效探测距离可达10 km;共得到30240对风速风向可对比统计点,风速的相关系数为0.82,系统差、标准差分别为0.586 m、5.38 m/s;风向的相关系数为0.94,系统差、标准差分别为5.93°、37.98°,两者的一致性较好。把5 km高度以下的数据按1000 m一层进行分层,分析各层风速、风向的相关系数、系统差和标准差显示。结果表明在1000~2000 m高度层激光雷达探测风廓线与L波段探空雷达的一致性最好,并对产生原因进行了分析。对于非相干多普勒激光雷达,探测数据的精度同时受到回波信号信噪比及低空气溶胶迅速变化的影响。
Doppler lidar has the characteristics of high precision and high spatial-temporal resolution in the detection of clear-air atmospheric wind field. The on-board incoherent Doppler lidar from CMA meteorological center is based on hyperspectral technique, which can detect atmospheric wind profile, horizontal and fan-shaped wind field. From March to April, 2011, synchronous contrast observation is carried out with the lidar and L-band radiosonde at the Southern Suburb Observation Station of Beijing. Fifty sets of comparable wind profile data with an average effective detection height of 6038 m are obtained. In the case of better visibility, the effective detection range is up to 10 km. A total of 30240 pairs of wind speed and wind direction contrast statistical points are obtained, and the correlation coefficient of wind speed is 0.82.The system difference and standard deviation are 0.586 m, 5.38 m/s, respectively. The correlation coefficient of wind direction is 0.94, the system difference is 5.93° and difference between the labels is 37.98°, the consistency between them is better. According to the layer of 1000 m, the wind speed and wind direction correlation coefficient, system difference and standard deviation of each layer are displayed below 5 km.Results show that the consistency of the laser radar detection wind profile and that of L band sounding radar during 1000~2000 m is the best, and the causes are analyzed. For incoherent Doppler lidar, the detection data accuracy is affected by both the signal-to-noise ratio of the echo signal and rapid change at low-level aerosol.
引文
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