STATISTICAL ANALYSIS OF POLARIMETRIC CHARACTERISTICS OF DIFFERENT SIZE HAILS FOR S-BAND DUAL POLARIZATION RADAR
-
摘要: 冰雹大小影响天气灾害的程度,为发展基于双偏振参量识别冰雹大小的算法,筛选了2019年、2020年山东省发生的33例冰雹事件,依据我国冰雹等级划分标准将其划分为小冰雹、大冰雹、特大冰雹,基于湿球0 ℃及冰雹融化特性确定了7个高度层,探讨了3类冰雹在不同高度层的双偏振参量分布特征,并获得了冰雹的偏振参量阈值。研究表明:在相同高度,冰雹越大雷达水平反射率因子Zh中位数越大、差分反射率因子Zdr中位数越小且基本为正值,但在-10~-20 ℃层,大冰雹的Zdr中位数易呈现负值;相关系数CC中位数随冰雹增大或高度降低而减小,但特大冰雹在0 ℃层到H0 ℃-1 km (0 ℃层下1 km) 之间由于融化比例较小CC反而会稍大;冰雹差分相移率KDP中位数在0 ℃层以上为0 °/km左右,在0 ℃层以下随高度降低冰雹融化而增加;大冰雹或特大冰雹基本特征是Zh大、CC小、Zdr小,CC可低至0.7以下,所有冰雹的Zdr、KDP可出现负值,小冰雹Zdr大于0 dB的情况较多,特大冰雹Zdr接近0 dB;-20 ℃层以上的Zh、0~-20 ℃层的CC和Zh、0 ℃层以下的CC、Zh、Zdr对冰雹大小比较敏感。Abstract: Hail size affects the degree of weather disasters. Aiming at developing an algorithm for hail size discrimination based on dual polarization parameters, the present study selected 33 hail events occurred in 2019 and 2020 in Shandong Province, and categorized them into small, large, and giant hails according to the Hail Classification Standard in China. Then seven altitude levels were determined based on the wet bulb 0 ℃ level and the properties of melting hails, the distribution characteristics of dual polarization variables of three types of hails at different altitude levels were discussed, and the thresholds of the polarization parameters for hails were obtained. The results show that the larger the hails are, the larger the median Zh and the smaller the median Zdr are at the same altitude, but the median Zdr are more likely to be negative in the -10~-20 ℃ layer. While the median CC basically decreases with the increase of hails or decrease of height, that of giant hails are slightly larger than the large hails in the 1 km below the 0 ℃ layer due to smaller melting ratio. The medians for KDP of hails are about 0 °/km above the 0 ℃ layer, and they increase with hail melting as height decreases below the 0 ℃ layer. Moreover, the basic characteristics of large or giant hails are large Zh, small CC less than 0.7 and small Zdr. Zdr and KDP can be negative for all hails, but Zdr is more likely to be more than 0 dB for small hails and close to 0 dB for giant hails. Finally, the more sensitive polarization parameters to hail size at different altitude layers include Zh above the -20 ℃ level, CC and Zh in the 0~-20 ℃ level, and CC, Zh and Zdr below the 0 ℃ level.
-
表 1 高度层信息
Hh、H0 ℃、H-10 ℃、H-20 ℃分别表示冰雹、0 ℃、-10 ℃及-20 ℃所在高度。 高度层分类 高度层范围 H7 Hh≥H-20 ℃ H6 H-10 ℃≤Hh<H-20 ℃ H5 H0 ℃≤Hh<H-10 ℃ H4 H0 ℃-1 km≤Hh<H0 ℃ H3 H0 ℃-2 km≤Hh<H0 ℃-1 km H2 H0 ℃-3 km≤Hh<H0 ℃-2 km H1 Hh<H0 ℃-3 km -
[1] 许焕斌, 段英. 冰雹形成机制的研究并论人工雹胚与自然雹胚的"利益竞争"防雹假说[J]. 大气科学, 2001, 25(2): 277-288. [2] 刘治国, 田守利, 邵亮, 等. 冰雹云垂直累积含水量密度与降雹大小的关系研究[J]. 干旱气象, 2008, 26(3): 22-28. [3] WITT M, EILTS D, STUMPF G J, et al. An enhanced hail detection algorithm for the WSR-88D[J]. Wea Forecasting, 1998, 13(2): 286-303. [4] 李柏. 天气雷达及其应用[M]. 北京: 气象出版社, 2011: 243-256. [5] 刁秀广, 黄秀韶, 任钟冬, 等. CINRAD/SA雷达冰雹探测算法效果检验及参数本地化[J]. 气象科技, 2007, 35(5): 727-731. [6] DOLAN B, RUTLEDGE S A. A Theory-based hydrometeor identification algorithm for X-band polarimetric radars[J]. J Atmos Oceanic Technol, 2008, 26(10): 2 071-2 088. [7] ZRNIĆ D, RYZHKOV A. Polarimetry for weather surveillance radars[J]. Bull Amer Meteor Soc, 1999, 80(3): 389-406. [8] LIM S, CHANDRASEKAR V, BRINGI V N. Hydrometeor classification system using dual polarization radar measurements: Model improvements and in situ verification[J]. IEEE Trans Geosci Remote Sens, 2005, 43(4): 792-801. [9] HEINSELMAN P L, RYZHKOV A V. Validation of polarimetric hail detection[J]. Wea Forecasting, 2006, 21(5): 839-850. [10] CHANDRASEKAR V, KERAENEN R, LIM S, et al. Recent advances in classification of observations from dual polarization weather radars[J]. Atmos Res, 2013, 119(1): 97-111. [11] PARK H S, RYZHKOV A, ZRNIĆ D, et al. The hydrometeor classification algorithm for the polarimetric WSR-88D: Description and application to an MCS[J]. Wea Forecasting, 2009, 24(3): 730-748. [12] AL-SAKKA H, BOUMAHMOUD A A, FRADON B, et al. A new fuzzy logic hydrometeor classification scheme applied to the French X-, C-, and S-band polarimetric radars[J]. J Appl Meteor Climatol, 2013, 52(10): 2 328-2 344. [13] WU C, LIU L P, WEI M, et al. Statistics-based optimization of the polarimetric radar hydrometeor classification algorithm and its application for a squall line in South China[J]. Adv Atmos Sci, 2018, 35(3): 296-316. [14] PICCA J, RYZHKOV A. A dual-wavelength polarimetric analysis of the 16 May 2010 Oklahoma City extreme hailstorm[J]. Mon Wea Rev, 2012, 140(4): 1 385-1 403. [15] JOHNS R H, DOSWELL Ⅲ C A. Severe local storms forecasting[J]. Wea Forecasting, 1992, 7(4): 588-612. [16] 刁秀广, 郭飞燕. 2019年8月16日诸城超级单体风暴双偏振参量结构特征分析[J]. 气象学报, 2021, 79(2): 181-195 [17] 刁秀广, 杨传凤, 张骞. 二次长寿命超级单体风暴参数与ZDR柱演变特征分析[J]. 高原气象, 2021, 40(3): 580-589. [18] 潘佳文, 魏鸣, 郭丽君, 等. 闽南地区大冰雹超级单体演变的双偏振特征分析[J]. 气象, 2020, 46(12): 1 608-1 620. [19] RYZHKOV A, GANSON S, KUMJIAN M, et al. Polarimetric characteristics of dry and melting hail at different radar wavelengths. Part Ⅱ: Practical implications[J]. J Appl Meteor Climatol, 2013, 52(12): 2 871-2 886. [20] MILLER R C. Notes on analysis and severe storm forecasting procedures of the Air Force Global Weather Central[R]. Air Weather Service, United State Air Force, 1972: 184. [21] 潘佳文, 高丽, 魏鸣, 等. 基于S波段双偏振雷达观测的雹暴偏振特征分析[J]. 气象学报, 2021, 79(1): 168-180. [22] 刁秀广. 2020年5月17日和6月1日山东强冰雹风暴双极化特征分析[J]. 海洋气象学报, 2021, 41(1): 68-81. [23] KALTENBOECK R, RYZHKOV A. Comparison of polarimetric signatures of hail at S and C bands for different hail sizes[J]. Atmos Res, 2013, 123(2): 323-336. [24] 曾智琳, 谌芸, 朱克云, 等. 广东省大冰雹事件的层结特征与融化效应[J]. 大气科学, 2019, 43(3): 598-617. [25] WALDVOGEL A, FEDERER B, GRIMM P. Criteria for the detection of hailcells[J]. J Appl Meteor, 1979, 18(12): 1 521-1 525. [26] 郑永光, 周康辉, 盛杰, 等. 强对流天气监测预报预警技术进展[J]. 应用气象学报, 2015, 26(6): 641- 657. [27] 俞小鼎. 关于冰雹的融化层高度[J]. 气象, 2014, 40(6): 649-654. [28] DOVIAK R J. 多普勒雷达与气象观测[M]. 北京: 气象出版社, 2013: 147-353. [29] 李博勇, 胡志群, 郑佳锋, 等. 利用贝叶斯方法改进华南地区冰雹识别效果[J]. 热带气象学报, 2021, 37(1): 112-125. [30] BALAKRISHNAN N, ZRNIĆ D S. Estimation of rain and hail rates in mixed-phase precipitation[J]. J Atmos Sci, 1990, 47(5): 565- 583. [31] AYDIN K, ZHAO Y. A computational study of polarimetric radar observables in hail[J]. IEEE Transactions on Geoence and Remote Sensing, 1990, 28(4): 412-422. [32] DENNIS A S, MUSIL D J. Calculations of hailstone growth and trajectories in a simple cloud model[J]. J Atmos Sci, 1973, 30(2): 278-288. [33] ILLINGWORTH A J, GODDARD J W F, CHERRY S M. 1987. Polarization radar studies of precipitation development in convective storms[J]. Quart J Roy Meteor Soc, 113: 469-489. [34] 刘春文, 郭学良, 段玮, 等. 云南一次典型降雹过程的冰雹微物理形成机理数值模拟研究[J]. 大气科学, 2021, 45(5): 1-16. [35] 孙伟, 曹舒娅, 沈建. 基于多源探测资料的"4.12"非典型冰雹特征分析[J]. 热带气象学报, 2021, 37(2): 218-232.