摘要
双偏振雷达的水凝物相态识别算法基于模糊逻辑方法建立,针对方法的可靠性和稳定性问题,利用2016-2017年暖季广州S波段双偏振雷达数据,从3个方面找出影响识别效果的关键因素并改进。使用模糊逻辑的累加值为检验依据,找出不合理的模糊规则,通过相态特征统计和权重矩阵修改加以改进。使用误差敏感性检验法系统,评估误差对识别效果的影响,发现反射率因子的误差在-0.5^+0.5 dBZ、差分反射率因子的误差在-0.1^+0.1 dB、雷达相关系数的误差在0~0.02、差分相移率的误差在-0.3^+0.9 dB的范围内,识别结果稳定性较好。此外,相态时空分布统计中发现底层冰雹面积异常增加,通过空间一致性检验可订正异常结果。
Most of recent hydrometeor classification schemes for dual-polarimtric radar are based on fuzzy logic.Due to the lack of true value of hydrometeors,it is difficult to verify whether classifications are right or not.Therefore,three methods are proposed,cumulative value test,algorithm sensitivity test and hydrometeors’distribution test.Cumulative value test is used to inspect the ability of classifying and distinguishing.When input data contains system deviation and noise,the output classification would also contain system deviation and noise.Hence,a method is proposed to test the sensitivity of system deviation and noise.Hydrometeor distribution test is to analyze whether the hydrometeor distribution is temporal and spatial continuous.Through these tests the reliability and stability of the algorithm are analyzed,and key factors which affect the classification can be found out.Using observations of precipitation processes in Guangzhou in spring and summer from 2016 to 2017,the efficiency of S-band dual-polarization doppler radar is examined.Main results show that the classifying hydrometeor relies on the membership function.Using cumulative value test,some hydrometeors are found out with inappropriate membership function.These membership functions are not consistent with real characteristics of hydrometeors,which are ground clutter(including that due to anomalous propagation),biological scatters,dry aggregated snow,crystals of carious orientations,light and moderate rain,and a mixture of rain and hail.The way to modify these membership functions is based on hydrometeor statistic characteristics.Another insufficiency of membership function is to distinguish similar hydrometeors,such as crystals of various orientations with dry aggregated snow and heavy rain with mixture of rain and hail.The method to modify membership function’s distinguishing ability is increasing parametric weights which has stronger discriminating ability.To ensure every hydrometeor has more than 90%stable results,the error of Zh is between-
作者
徐舒扬
吴翀
刘黎平
Xu Shuyang;Wu Chong;Liu Liping(College of Electronic Engineering,Chengdu University of Information Technology,Chengdu 610225;Chinese Academy of Meteorological Sciences,Beijing 100081)
出处
《应用气象学报》
CSCD
北大核心
2020年第3期350-360,共11页
Journal of Applied Meteorological Science
基金
国家重点研究发展计划(2018YFC1506101,2018YFC1507401)。
关键词
模糊逻辑
粒子相态识别
双偏振雷达
fuzzy logic
hydrometeor classification algorithm
dual-polarization radar
