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.