摘要
双偏振雷达是强对流天气分析和云微物理研究的重要探测设备,将多普勒天气雷达升级为双偏振雷达是我国未来几年强对流天气监测发展建设的重点计划,而双偏振雷达资料质量控制是其中的关键技术问题。针对国内首批业务布建的广东省S波段双偏振雷达网研发建立了一套完整的质量控制技术方案,除了重点解决非气象回波外,还考虑了非标准波束遮挡和径向高频脉动问题。在飑线、暴雨和台风3类华南季风区强天气个例的应用表明,基于模糊逻辑的水凝物分类、偏振量(零滞后互相关系数、信噪比和比差分相位)阈值检查和杂波剔除能有效剔除非气象回波,抑制异常传播波束导致的虚假回波;线性内插较好地弥补了非标准波束遮挡带来的观测缝隙;中值滤波和滑动平均既过滤了偏振观测量在雷达径向的高频脉动,又保留了主要的偏振雷达观测特征。质量控制后的气象回波约占有效观测(反射率因子大于-30 dBZ)的40%,其偏振量取值分别为反射率因子大于5 dBZ、零滞后互相关系数大于0.8和差分反射率为-0.2～4 dB。
The polarimetric radar is an important detection device whose measurements can be used for severe convective weather analysis and cloud microphysics progress research. Upgrading the traditional Doppler weather radar to polarimetric radar is a key part of severe convective weather monitoring program of China in the next few years, and the quality control of polarimetric radar measurements is key technical issue of the monitoring program. In Guangdong Province, based on the domestic and international mainstream quality control algorithms and relevant experience, a quality control system is developed for S-band polarimetric radars, to deal with the non-meteorological echo, non-standard blockage and high frequency noise in the radar radial, which have negative impacts on application of polarimetric radar measurements in data assimilation. The system is applied to the typical severe convective weather case in South China monsoon region, including a rainfall case, a severe convection case and a typhoon case in 2017. Evaluation results show that a combination of the hydrometeor classification screening based on fuzzy logic, co-polar crosscorrelation coefficient （ρ_（HV））, signal-to-noise ratio （SNR） and specific differential phase （K_（DP）） thresholding and despeckling can remove most non-meteorological echoes, and suppress virtual echo caused by anomalous propagation efficiently. Non-meteorological echoes include ground clutter, biological scatters, partial clear-air echo and radiographic noise due to anomalous propagation. A linear interpolation is employed to fill the small gap（the width of which is less than 5°） caused by non-standard blockage. A median filter and radial smooth are found effective in filtering out high frequency noise in the radar radial while maintaining polarimetric radar characteristics. After quality control, the meteorological echo is clearer and more prominent, and accounts for about 40% of valid observation which is defined by reflectivity （Z_H） being larger than -
作者
王洪
孔凡铀
Jung Youngsun
吴乃庚
尹金方
Wang Hong;Kong Fanyou;Jung Youngsun;Wu Naigeng;Yin Jinfang(Guangzhou Institute of Tropical and Marine Meteorology/Key Laboratory of Regional Numerical Weather Prediction,CMA,Guangzhou 510080;State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081;Center for Analysis and Prediction of Storms,University of Oklahoma,Oklahoma 73072,USA)
出处
《应用气象学报》
CSCD
北大核心
2018年第5期546-558,共13页
Journal of Applied Meteorological Science
基金
国家自然科学基金项目(41705035
41475102
41675021
41705020)
国家重点基础研究发展计划(2015CB452802)
灾害天气国家重点实验室开放课题(2018LASW-B13)
广东省科技计划项目(2017A020219005
2017B020218003)
关键词
双偏振雷达
质量控制
非气象回波
polarimetric radar
quality control
non meteorological echo
