偏振雷达参量对融化层回波的探测敏感性分析

The Detection Sensitivity Analysis of Dual Polarization Radar Parameters for Melting Layer

融化层特征的研究及其微物理性质的识别在云物理降水研究、人工影响天气、航空飞行以及积云参数化方案修订等都有重要意义。利用南京信息工程大学C波段双偏振雷达(简称为NUIST C-Pol雷达)的回波强度Z,差分反射率因子ZDR、差分传播相位常数KDP、正交相关系数ρHV,研究融化层回波(即零度层亮带,简称亮带)敏感性及其对应水凝物微物理特征。根据NUIST C-Pol雷达2014年实测数据,分析亮带的偏振参数探测特性时发现相关系数最敏感,它比其他参量更早出现亮带特征;其次是差分反射率因子、差分传播相位常数,最后才在回波强度上看到明显的亮带。进一步地,探讨了亮带中相关系数的探测敏感性及其数值减小的机理。研究结果对于用双偏振雷达参数研究云降水物理特性具有理论和应用价值。

Identifying the characteristics of the melting layer and its microphysical properties is of great importance for the research of cloud physics precipitation, weather modification, aircraft flight and the revision of cumulus parameterization scheme. NUIST C-band dual-polarization radar data（referred to as NUIST C-Pol radar） , i. e. reflectivity Z, differential reflectivity ZDR, specific differential phase -DP, and correlation coefficients pm are used to research the echo sensitivity of the melting layer（ referred to as bright band） and the microphysical characteristics of its corresponding hydrometeor. Take the detection data of the NUIST C-Pol Radar in 2014 for instance, the correlation coefficients is the most sensitive in the process of the polarization parameters detection sensitivity analysis of the bright band. The correlation coefficients firstly shows the characteristics of the bright band, followed by the differential reflectivity and specific differential phase, and at last the bright band can be seen obviously on the reflectivity picture. Furthermore, the detection sensitivity of the correlation coefficients to the bright band and the mechanism of the correlation coefficient decrease in the bright band is discussed. The results of the research are of com-paratively high theoretical and practical value in the application of the study of cloud and precipitation physical properties by dualpolarization radar parameters.