大风背景下首都机场两条跑道低空风切变特征统计

利用北京首都机场18R-36L、19-01两条跑道南端入口附近的两台相干多普勒测风激光雷达的RHI扫描模式探测风速数据，分别计算在不同的风速、风向区间内两条跑道及其南下滑道区域600 m高度下各高度层的径向风速平均偏差。结果表明:在西北大风背景下，18R-36L跑道上空风速与同高度风速对比有偏小现象，这与在相同背景风条件下三条跑道接地带区域观测到的风速特征相吻合。另外风速偏小现象在300°～330°风向区间最显著，且偏差最小值区域出现在18R跑道入口附近。通过风切变强度因子进一步统计在西北大风条件下36L和01跑道下滑道区域风切变发生的强度及位置。统计表明:36L跑道的风切变频次及强度整体高于01跑道，其中300°～330°风向区间两条跑道的风切变事件发生最频繁，且顺风风切变频次明显高于逆风风切变频次，但逆风风切变发生的高度比顺风风切变发生的高度要低。

Low-level wind shear characteristic statistic of two runways of Beijing Capital International Airport based on strong wind background

Data available in this study came from RHI scanning mode of two sets of coherent Doppler lidar which housed near the south entrance of runway 18R-36L and runway 19-01 in Beijing International Capital Airport, respectively. Average deviation of radial velocity at multiple heights below 600 meter above the ground level over two runways and their south glide path areas in different wind speed and direction ranges were calculated separately. Results show that under the strong northwest wind background radial wind speed over runway 18R-36L is relatively lower than other areas with same altitude, which is consistent with characteristic of wind speed observed in three runway touch down zones under the same wind background. In addition, this phenomenon is most significantly appeared in wind direction range of 300°-330° and the minimum negative deviation area appeared near the entrance of runway 18R. The intensity factor of wind shear was used for further statistics to determine the intensities and locations of low-level wind shear events along the glide path of runway 36L and 01 in the strong northwest wind background. Statistics explain that the frequencies and the intensities of low-level wind shear happened on runway 36L are obviously higher than those happened on runway 01 in the same wind context. In 300°-330° direction range frequencies of low-level wind shear of two runways are both the highest and the frequency of following?wind shear is significantly higher than the against wind shear, even though the heights of occurrence with following wind shear are relatively lower than the against wind.