Rayleigh散射Doppler激光雷达风场反演方法改进

Improvement of wind retrieval algorithm for Rayleigh Doppler lidar

在Rayleigh敞射Doppler激光雷达的风场反演过程中,除了温度、压强等因素之外,风速反演结果的准确性还受到Mie敞射信号的影响.当Mie散射信号较强时,尤其是遇到高层云或火山灰等情况,如果仍不号虑气溶胶信号,由于温度不确定度和气溶胶信号的综合影响,风速反演结果将与真值偏差很大.本文提出了利用激光雷达在垂直方向的测量信同时反演后向散射比和大气温度的非线性迭代算法,并优化给出了最佳的初始发射激光工作点.仿真试验结果表明:该方法可以准确有效地反演后向散射比;将该方法结合非线性迭代风速反演方法,可以有效消除气溶胶后向敞射信号的影响,进一步提高大气风速和温度的反演精度.

In the process of wind retrieval for Rayleigh Doppler lidar,besides atmospheric temperature and pressure,the accuracy of the wind retrieval result is also affected by Mie signal.When the Mie scattering sigal is large,especially in the cases such as high altitude clouds or volcanic ash and so on,the wind retrieval result will largely deviate from the ture value if the aerosol signal is ignored due to temperature uncertainty and Mie signal contamination.A nonlinear iterative algorithm is proposed,which can retrieve both wind and atmospheric temperature by using the mesured signal with outgoing laser pointing to the zenith.The initial operating point of laser is optimized.Simulation results show that the proposed algorithm can retrieve scattering ratio effectively,and by combination with the nonlinear iterative algorithm of wind retrieval,this algorithm can eliminate the effect of aerosol backscattering signal and then improve the atmopheric wind speed and the temperature retrieval accuracy effectively.