基于相干多普勒激光雷达的斜程湍流参数反演方法研究

Inversion methods of slant turbulence parameters based on coherent Doppler lidar

大气湍流广泛存在于大气中,其中斜程湍流对航空航天、天文观测等会产生不可忽视的影响。一方面利用相干多普勒测风激光雷达获得的高时空分辨风场探测数据,另一方面基于Kolmogorov局地均匀各项同性理论,即在惯性子区内湍流的特征只与湍能耗散率ε有关,将速度结构函数法应用到飞机着陆阶段下滑道扫描模式中,通过实测数据的速度结构函数与模型速度结构函数最小二乘法拟合,从而估算激光雷达扫描范围内的大气湍流参数(径向风速方差、湍流积分尺度和ε等)。根据下滑道扫描区域数据的时空分布特征,给出大气湍流参数的斜程空间分布图,并与同步观测的飞机下滑道风切变强度数据进行了对比分析,发现两者具有较好的一致性,证实了斜程湍流参数反演方法的可靠性。

Atmospheric turbulence is widespread in the atmosphere,in which the slant turbulence has a significant impact on aerospace and military activities.On the one hand,the high spatial and temporal resolution wind field data obtained from the coherent Doppler lidar is used.On the other hand,according to the velocity structure function method based on Kolmogorov's local uniform homogeneous theory,i.e.the characteristics of turbulence in the inertial sub-region are only related to the turbulent eddy dissipation rateε,the velocity structure function method is applied to the lidar glide-path scans mode for aircraft landing period.By fitting the measured data velocity structure function with the model velocity structure function least square,the atmospheric turbulence parameters(wind speed variance,turbulence integration scale andε,etc)within the lidar swath are estimated.Furthermore,based on the spatial and temporal distribution characteristics of the data in the slant scanning area,the slant spatial distribution of the atmospheric turbulence parameters is presented and compared with the wind-shear intensity data obtained from the lidar glide-path scans mode developed by Ocean University of China.It is found that the two data are in good agreement,which validates the reliabiltiy of the proposed slant turbulence parameter retrieval method.