双线偏振雷达差分传播相移的小波滤波初探

根据中国气象科学研究院灾害天气国家重点实验室的车载C波段双线偏振多普勒雷达外场观测资料，利用Daubechies小波对雷达观测的差分传播相移ΦDP进行滤波处理，并与滑动平均和中值滤波这两种常规处理方法的滤波效果进行对比分析。结果表明，Daubechies小波方法不仅同两种常规处理方法一样能有效剔除差分传播相移ΦDP存在的各种脉动与毛刺，使ΦDP数据具有更好的连续性和平滑度，还能有效地保留非气象回波信息，方便对其进行地物识别等后续处理； 此外，其对弱信号的滤波效果也有显著提高，滤波后的ΦDP及其估算的差分传播相移率KDP与反射率因子ZH均有较好的对应关系。

Preliminary study on wavelet filtering of differential propagation phase shift for dual linear polarization radar

In this paper, the wavelet analysis method for filtering application of differential propagation phase shift for dual-linear polarization radar has been discussed preliminarily. Based on the observation in field experiments by a C-band Polarimetric Doppler Radar on Wheel (CPDRW) which was built in the State Key Laboratory of Severe Weather (LaSW), Chinese Academy of Meteorological Sciences (CAMS),Daubechies wavelet is used to filter the differential propagation phase shift ΦDP, and comparative analysis with the effect of moving average and median filtering, the two conventional processing methods in the filtering effect, are performed. The results show that this method can eliminate the pulsation and burr existing in the differential propagation phase shift ΦDPeffectively and has more obvious filtering effect than the other two conventional methods. Not only has ΦDP data better continuity and smoothness, but also retains effectively the non-meteorological echo information to facilitate the subsequent processing such as ground clutter identification. In addition, it has also significantly improved the weak signal filtering effect. Both filtered ΦDP and its estimations of specific differential propagation phase shift KDP correspond better with the reflectivity ZH and differential reflectivity ZDR.