激光测风雷达PPI扫描监测风切变的数值模拟

Numerical simulation for wind shear detection with PPI scanning based on wind lidar

低空风切变严重威胁飞机起降安全,而激光测风雷达在晴空风切变监测方面具有显著优势,但其监测性能受到风场特点和监测算法的影响。由于无法对局地空间风场进行时空同步精细化探测,且风场具有阵性,导致风切变监测会出现虚警率、漏报等现象,只能通过数值模拟仿真的方式,对不同风场的监测性能进行分析评估。本文首先仿真构建了四种具有代表性的风场类型,然后模拟激光测风雷达平面-位置显示(Plane Position Indication,PPI)扫描方式获取不同仿真风场下的径向风速数据,最后利用八邻域系统算法对径向风速数据进行风切变监测,验证不同类型风场下激光测风雷达PPI扫描方式监测风切变算法的有效性。结果表明,激光测风雷达PPI扫描结果能够真实地反映风场情况;八邻域系统算法能够有效识别风切变;在进行风切变检测时,应尽可能地考虑到多个方位上的切变值,避免漏报。

Low level wind shear seriously threatens the safety of aircraft taking off and landing.Wind lidar has significant advantages in wind shear detecting in clear sky,but its detecting performance is affected by the characteristics of the wind field and the detecting algorithm.As the local spatial wind field cannot be refined in time and space,and the wind field is gusty,the wind shear detecting will have false alarm rates and missed reports.The detecting performance of wind lidar in different wind fields can only be analyzed and evaluated through numerical simulation.This paper first constructs four representative wind fields,then simulates the wind lidar PPI scanning method to obtain the radial wind speed data under different simulated wind fields,finally uses the eight-neighbor system algorithm to perform wind shear detection on the radial wind speed data,to verify the effectiveness of the PPI scanning method of wind lidar for monitoring wind shear in different wind field.The results show that the PPI scanning results of the wind lidar can truly reflect the situation of the wind field.The eight-neighbor system algorithm can effectively identify wind shear.In the process of wind shear detection,the shear values in multiple directions should be considered as far as possible to avoid missing reports.