无线电掩星滑动频谱方法和后传播方法的分析比较

本文详细介绍了滑动频谱方法,并通过模拟仿真和实测资料处理与后传播方法进行比较. 通过对模拟仿真信号反演发现:后传播方法和滑动频谱方法均能削弱大气多路径的影响,后传播方法在一定程度上优于滑动频谱方法;在模拟信号的相位中加入高斯噪声对后传播方法影响不大,但对滑动频谱方法影响较大,尤其在边界层以下. 分别用后传播方法和滑动频谱方法对2007年第71天至73天共约4500个COSMIC掩星数据进行处理. 将折射率反演结果与ECMWF分析场资料进行统计比较,结果显示:滑动频谱方法反演的掩星廓线深度大于后传播方法;后 关键词： GPS/LEO掩星 多相位屏模型 后传播方法 滑动频谱方法

Comparison between sliding spectral method and back propagation method for radio occultation data

The sliding spectral (SS) method of processing radio occultation data in multipath zone is introduced in detail and compared with back propagation (BP) method through processing simulated data and COSMIC soundings. The modeled signals are inverted with the use of two methods: BP method and SS method. Both methods can solve the problem of calculating bending angle profiles in multipath regions. Better agreement with Abel integral is indicated by the BP method. The BP method is almost free from noise, while the SS method will be affected severely by noise. About 4500 COSMIC radio occultation soundings are retrieved by the BP method and the SS method, and the statistical comparison of retrieved refractivity with that from ECMWF analyses shows that the SS method has better penetration ability than the BP method in the lower moist troposphere. The mean of fractional difference in refractivity retrieved by the BP method is generally smaller than that by the SS method.