Error Evaluation and Hydrometeor Classification Method of Dual Polarization Phased Array Radar
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摘要: 选取2020年3—9月深圳求雨坛的X波段双偏振相控阵雷达探测数据, 与同位置的S波段双偏振雷达进行对比。通过一定限制条件定量分析引入误差的原因, 发现反射率因子ZH和差分反射率ZDR的标定误差和随机误差较大, 其中ZH误差变化范围为-0.5~4.5 dB, ZDR误差变化范围为-0.7~0.2 dB。在上述较大误差影响下, 传统模糊逻辑相态识别方法的水凝物相态识别结果不可靠, 因此根据不同相态的雷达参量特征范围以及融化层高度建立基本结构为二叉树的决策树相态识别方法。针对上述方法的实际应用效果, 分别从水凝物相态识别结果对误差的敏感性和空间分布的合理性进行评估, 结果表明: 决策树相态识别方法的水凝物相态识别结果稳定性高于模糊逻辑相态识别方法, 且在对流云中的水凝物相态分布更加合理, 能够发挥X波段双偏振相控阵雷达在研究云内水凝物相态演变的优势。Abstract: Phased array radar is faster in scanning speed than mechanical scanning radar, but due to the influence of antenna structure and attenuation, phased array radar will produce larger system error and random error. The mainstream fuzzy logic hydrometeor classification method has little difference in the weight coefficients of each parameter, and the calculated composite values are often close, so the hydrometeor classification results are easily affected by data errors. The detection data of the X-band dual polarization phased array radar at Qiuyutan, Shenzhen, from March to September in 2020 are compared with the S-band dual polarization radar at the same location. The points close to the elevation, azimuth and radial distance of the two radars are obtained to establish matching datasets to calculate the errors of X-band dual-polarization phased array radar. Quantitative analysis of the causes for the introduction of errors through certain restriction conditions reveals that the calibration error and random error of the reflectance factor ZH and the differential reflectance ZDR are relatively large. The error range of ZH is -0.5-4.5 dB, and the error of ZDR is -0.7-0.2 dB. After the preliminary correction of calibration error and random error, it is found that there are still some errors in data, which make the hydrometeor classification result of fuzzy logic method unreliable, so the decision tree hydrometeor classification method with the basic structure of binary tree is established according to the characteristic range of radar parameters of different hydrometeors and the height of the melting layer. In order to verify the practical application effects of the above methods, the error sensitivity of hydrometeor classification results and the rationality of hydrometeor spatial distribution are evaluated respectively. Typical examples are selected to further evaluate the rationality of the decision tree hydrometeor classification method by comparing the parameters and hydrometeor classification results of X-band dual polarization phased array radar and S-band dual polarization radar. The evaluation results show that the stability of the decision tree hydrometeor classification method is higher than that of the fuzzy logic method, and the hydrometeor distribution in the convective cloud is more reasonable, which can give full play to the advantage of X-band dual polarization phased array radar in studying the phase evolution of particles in the cloud.
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图 11 DHC方法和FHC方法对于2020年5月11日23:00 X-PAR和S-POL探测水凝物相态识别结果
(6.3°仰角, 相邻距离圈间距为15 km,+为雷达位置)
Fig. 11 Hydrometeor classification results of DHC method and FHC method in X-PAR and S-POL at 2300 BT 11 May 2020
(the elevation: 6.3°, the distance between adjacent circles is 15 km, + deontes the location of radar)
表 1 X-PAR不同误差的限制条件
Table 1 Limiting conditions for different errors of X-PAR
误差种类 表征误差的变量 限制条件 数据处理 距离 ΦDP 其他限制 标定误差 时间 滤波 20~30 km ≤5° 仰角(X-PAR: 4.5°,S-POL: 4.3°) 仰角 滤波 20~30 km ≤5° 去除标定随时间的误差 衰减订正误差 ΦDP 滤波 25~30 km ≥5° 仰角(X-PAR: 4.5°, S-POL: 4.3°), 去除标定随时间的误差 波束展宽误差 距离 滤波 所有距离 ≤5° 仰角(X-PAR: 4.5°, S-POL: 4.3°), 去除标定随时间的误差 随机误差 ZH标准差、ZDR标准差 未滤波 20~30 km ≤5° 仰角(X-PAR: 4.5°, S-POL: 4.3°), 去除标定随时间的误差 -
[1] 张光义. 相控阵雷达原理. 北京: 国防工业出版社, 2009: 13-21.Zhang G Y. Principles of Phased array Radar. Beijing: National Defense Industry Press, 2009: 13-21. [2] 吴翀, 刘黎平, 汪旭东, 等. 相控阵雷达扫描方式对回波强度测量的影响. 应用气象学报, 2014, 25(4): 406-414. doi: 10.3969/j.issn.1001-7313.2014.04.003Wu C, Liu L P, Wang X D, et al. The measurement influence of reflectivity factor caused by scanning mode from phased array radar. J Appl Meteor Sci, 2014, 25(4): 406-414. doi: 10.3969/j.issn.1001-7313.2014.04.003 [3] 马舒庆, 陈洪滨, 王国荣, 等. 阵列天气雷达设计与初步实现. 应用气象学报, 2019, 30(1): 1-12. doi: 10.11898/1001-7313.20190101Ma S Q, Chen H B, Wang G R, et al. Design and initial implementation of array weather radar. J Appl Meteor Sci, 2019, 30(1): 1-12. doi: 10.11898/1001-7313.20190101 [4] 吴翀, 刘黎平, 仰美霖, 等. X波段双偏振雷达相态识别与拼图的关键技术. 应用气象学报, 2021, 32(2): 200-216. doi: 10.11898/1001-7313.20210206Wu C, Liu L P, Yang M L, et al. Key technologies of hydrometeor classification and mosaic algorithm for X-band polarimetric radar. J Appl Meteor Sci, 2021, 32(2): 200-216. doi: 10.11898/1001-7313.20210206 [5] 刘黎平, 吴林林, 吴翀, 等. X波段相控阵天气雷达对流过程观测外场试验及初步结果分析. 大气科学, 2014, 38(6): 1079-1094. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXK201406006.htmLiu L P, Wu L L, Wu C, et al. Field experiment on convective precipitation by X-Band phased-array radar and preliminary results. Chinese J Atmos Sci, 2014, 38(6): 1079-1094. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXK201406006.htm [6] 刘俊, 黄兴友, 何雨芩, 等. X波段相控阵气象雷达回波数据的对比分析. 高原气象, 2015, 34(4): 1167-1176. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX201504028.htmLiu J, Huang X Y, He Y Q, et al. Comparative analysis of X-Band phased array antenna weather radar measurements. Plateau Meteorology, 2015, 34(4): 1167-1176. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX201504028.htm [7] 刘黎平, 吴翀, 汪旭东, 等. X波段一维扫描有源相控阵天气雷达测试定标方法. 应用气象学报, 2015, 26(2): 129-140. doi: 10.11898/1001-7313.20150201Liu L P, Wu C, Wang X D, et al. Test and calibration methods for X-band active phased-array weather radar. J Appl Meteor Sci, 2015, 26(2): 129-140. doi: 10.11898/1001-7313.20150201 [8] Ryzhkov A V, Schuur T J, Burgess D W, et al. The joint polarization experiment: Polarimetric rainfall measurements and hydrometeor classification. Bull Amer Meteor Soc, 2005, 86(6): 809-824. doi: 10.1175/BAMS-86-6-809 [9] Park S G, Bringi V N, Chandrasekar V, et al. Correction of radar reflectivity and differential reflectivity for rain attenuation at X band. Part I: Theoretical and empirical basis. J Atmos Oceanic Technol, 2005, 22(11): 1621-1632. doi: 10.1175/JTECH1803.1 [10] 杨金红, 高玉春, 程明虎, 等. 相控阵天气雷达波束特性. 应用气象学报, 2009, 20(1): 119-123. doi: 10.3969/j.issn.1001-7313.2009.01.016Yang J H, Gao Y C, Cheng M H, et al. Beam characteristics analysis on phased array weather radar. J Appl Meteor Sci, 2009, 20(1): 119-123. doi: 10.3969/j.issn.1001-7313.2009.01.016 [11] 张蔚然, 吴翀, 刘黎平, 等. 双偏振相控阵雷达与业务雷达的定量对比及观测精度研究. 高原气象, 2021, 40(2): 424-435. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX202102019.htmZhang W R, Wu C, Liu L P, et al. Research on quantitative comparison and observation precision of dual polarization phased array radar and operational radar. Plateau Meteorology, 2021, 40(2): 424-435. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX202102019.htm [12] Zadeh L A. Fuzzy algorithms. Information & Control, 1968, 12(2): 94-102. [13] Straka M J, Zrnic D S. An Algorithm to Deduce Hydrometeor Types and Contents from Multiparameter Radar Data//26th Conference on Radar Meteorology, 1993: 513-515. [14] Zrnic D S, Ryzhkov A, Straka J, et al. Testing a procedure for automatic classification of hydrometeor types. J Atmos Oceanic Technol, 2001, 18(6): 892-913. doi: 10.1175/1520-0426(2001)018<0892:TAPFAC>2.0.CO;2 [15] 曹俊武, 刘黎平, 葛润生. 模糊逻辑法在双线偏振雷达识别降水粒子相态中的研究. 大气科学, 2005, 29(5): 827-836. doi: 10.3878/j.issn.1006-9895.2005.05.15Cao J W, Liu L P, Ge R S. A Study of fuzzy logic method in classification of hydrometeors based on polarimetric radar measurement. Chinese J Atmos Sci, 2005, 29(5): 827-836. doi: 10.3878/j.issn.1006-9895.2005.05.15 [16] Park H S, Ryzhkov A V, Zrnic D S, et al. The hydrometeor classification algorithm for the polarimetric WSR-88D: Description and application to an MCS. Wea Forecasting, 2009, 24(3): 730-748. [17] 徐舒扬, 吴翀, 刘黎平. 双偏振雷达水凝物相态识别方法的参数改进. 应用气象学报, 2020, 31(3): 350-360. doi: 10.11898/1001-7313.20200309Xu S Y, Wu C, Liu L P. Parameter improvements of hydrometeor classification algorithm for the dual-polarization radar. J Appl Meteor Sci, 2020, 31(3): 350-360. doi: 10.11898/1001-7313.20200309 [18] Hunt E B, Marin J, Stone P J. Experiments in Induction. New York: Academic Press, 1966. [19] 傅佩玲, 胡东明, 黄浩, 等. 台风山竹(1822)龙卷的双极化相控阵雷达特征. 应用气象学报, 2020, 31(6): 706-718. doi: 10.11898/1001-7313.20200606Fu P L, Hu D M, Huang H, et al. Observation of a tornado event in outside-region of Typhoon Mangkhut by X-band polarimetric phased array radar in 2018. J Appl Meteor Sci, 2020, 31(6): 706-718. doi: 10.11898/1001-7313.20200606 [20] 王洪, 孔凡铀, Jung Youngsun, 等. 面向资料同化的S波段双偏振雷达质量控制. 应用气象学报, 2018, 29(5): 546-558. doi: 10.11898/1001-7313.20180504Wang H, Kong F Y, Jung Y S, et al. Quality control of S-band polarimetric radar measurements for data assimilation. J Appl Meteor Sci, 2018, 29(5): 546-558. doi: 10.11898/1001-7313.20180504 [21] 蔡启铭, 徐宝祥, 刘黎平. 降雨强度、雨区衰减与双线偏振雷达观测量关系的研究. 高原气象, 1990, 9(4): 347-355. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX199004000.htmCai Q M, Xu B X, Liu L P. A study of the relation between raininess, extinction of rain cloud and parameters measured by a dual linear polarization radar. Plateau Meteorology, 1990, 9(4): 347-355. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX199004000.htm [22] Giangrande S E, Krause J M, Ryzhkov A V. Automatic designation of the melting layer with a polarimetric prototype of the WSR-88D radar. J Appl Meteor Climatol, 2008, 47(5): 1354-1364. doi: 10.1175/2007JAMC1634.1 [23] 肖艳姣, 刘黎平. 三维雷达反射率资料用于层状云和对流云的识别研究. 大气科学, 2007, 31(4): 645-654. doi: 10.3878/j.issn.1006-9895.2007.04.09Xiao Y J, Liu L P. Identification of stratiform and convective cloud using 3D radar reflectivity data. Chinese J Atmos Sci, 2007, 31(4): 645-654. doi: 10.3878/j.issn.1006-9895.2007.04.09 [24] 丁青兰, 刘黎平, 葛润生, 等. 双线偏振多普勒雷达测量精度的理论分析. 应用气象学报, 2003, 14(1): 30-38. doi: 10.3969/j.issn.1001-7313.2003.01.004Ding Q L, Liu L P, Ge R S, et al. Theoretical analysis of measurement accuracy of dual linear polarization Doppler radar. J Appl Meteor Sci, 2003, 14(1): 30-38. doi: 10.3969/j.issn.1001-7313.2003.01.004 [25] 朱士超, 袁野, 吴月, 等. 江淮地区孤立对流云统计特征. 应用气象学报, 2019, 30(6): 690-699. doi: 10.11898/1001-7313.20190605Zhu S C, Yuan Y, Wu Y, et al. Statistical characteristics of isolated convection in the Jianghuai Region. J Appl Meteor Sci, 2019, 30(6): 690-699. doi: 10.11898/1001-7313.20190605