低空风切变是对飞机飞行安全产生重要影响的因素。利用三维扫描型测风激光雷达2023年3月期间在广州白云机场的观测数据，在对测风激光雷达的观测数据进行预处理的基础上，提出了结合自适应窗口的二维合成风切变识别和时间风切变识别的两步识别方法（简称风切变两步识别法），对比了风切变两步识别法和二维合成法对风切变的识别效果，并对识别的风切变的演变进行了分析。结果表明：数据预处理有效地去除了测风激光雷达观测的孤立点及径向数据间的脉动，并对缺测数据进行了填补；风切变两步识别法有利于风切变的提前预警，在2023年3月广州白云机场观测期间，风切变两步识别法共识别到25起风切变，其中有21起比二维合成风切变识别方法提前预警，平均早预警3 ~ 5 min，且对时间维度和空间维度风切变均有较好的识别告警作用；识别的风切变过程大多发生于中午前后（11：00—15：00）时且持续时间多在15 min左右，风切变位置受背景风场影响较大。研究中提出的风切变两步识别法能更早、更全面地识别出低空风切变，有助于提高风切变预警的准确性，为飞机飞行安全提供保障。

Low level wind shear is an important factor affecting aircraft flight safety. Based on the observations from a three-dimensional scanning wind lidar at Baiyun Airport, Guangzhou during March 2023, the measurements from the wind lidar were preprocessed firstly. Then, TSSI (two-step identification method for wind shear) was proposed, which combined TDSI (two-dimensional synthetic wind shear identification) method with an adaptive window and the temporal wind shear identification method. The wind shear results recognized by the TSSI and TDSI methods were compared, and the evolutions of wind shear were analyzed. The main conclusions are as follows. Data preprocessing effectively removes isolated points and radial fluctuations observed by wind lidar, and fills in the missing data. The TSSI method is conducive to early warning of wind shear. During the observation period at Baiyun Airport, Guangzhou in March 2023, a total of 25 wind shear processes are identified by the TSSI. Among them, 21 cases are warned ahead of the TDSI, with an average warning time of 3 ~ 5 minutes, and TSSI also has a good alarm recognition function for both time and space dimension wind shear. Most of the identified wind shear processes occur around noon (e. g. 11:00-15:00) and last for about 15 minutes. The wind shear position is greatly influenced by the background wind field. The TSSI method proposed in this study can identify low-level wind shear earlier and more comprehensively, which is helpful to improve the accuracy of wind shear warning and provide guarantees for aircraft flight safety.