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Retrieval of Air Vertical Velocity and Droplet Size Distribution in Squall Line Precipitation Using C-FMCW Radar
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摘要: 垂直指向探测的C波段调频连续波雷达具有高灵敏度和高时空分辨率等特点, 以2016年5月广东两次飑线降水为例, 结合同址K波段微雨雷达和地面激光雨滴谱仪, 探究C波段调频连续波雷达两种反演大气垂直速度(Va)和雨滴谱的方法:粒子平均下落末速度(Vt)-反射率因子(Ze)关系法(简称经验关系法)和小粒子示踪法(简称示踪法)。结果表明:经验关系法和示踪法反演的上升和下沉气流的时空分布基本一致;当地面雨强R≤1 mm·h-1, 经验关系法反演的雨滴谱与雨滴谱仪观测结果更接近;当1<R≤10 mm·h-1时, 两种方法反演的雨滴谱均与雨滴谱仪观测及微雨雷达产品较吻合;当R>10 mm·h-1时, 两种方法反演的中雨滴数浓度与雨滴谱仪观测结果接近, 但大雨滴数浓度较低;从各物理量时序变化看, 经验关系法反演结果更接近雨滴谱仪观测结果。Abstract: The zenith C-band frequency modulation continuous wave(C-FMCW) radar has good detection capability with high temporary-spatial resolution and large dynamic range. The Doppler spectral density data of two squall lines precipitation cases at Longmen of Guangdong are utilized to retrieve the air vertical velocity (Va) in clouds and droplet size distribution (DSD). The empirical relation method (checking relationship between mean particle falling velocity (Vt) and reflectivity factor) and the small-particle-trace method are explored to retrieve the air vertical velocity in clouds. And then the droplet size distribution is retrieved from the translated Doppler spectral density by a velocity-diameter relation. The retrieved DSD of two squall lines are then compared and validated with the observation of K-band micro rain radar and second-generation Parsivel disdrometer. The retrieved Va by the empirical relation method is slightly smaller for strong monomer than that by the small-particle-trace method and slightly larger for weak convective precipitation, but Vt is the opposite. The absolute value of Vt negative velocity by the empirical relation method and the small-particle-trace method corresponds to the moment of large particles and heavy rain observed by Parsivel disdrometer, indicating that Va of two methods is basically reliable. The comparison in DSD retrieval show that the number of small droplets observed by radar is higher, but Parsivel disdrometer may underestimate it. The results of the empirical relation method are closer to micro rain radar and Parsivel disdrometer when rain rate is below 1 mm·h-1. The medium droplets obtained by radar retrieval are consistent with Parsivel disdrometer measurements, but the concentration of large droplets is low when rain rate is stronger than 10 mm·h-1. The retrieval results of both methods are close to Parsivel disdrometer and micro rain radar when rain rate is between 1 mm·h-1 and 10 mm·h-1. The strong convection makes droplets rupture severer in the peak area of heavy precipitation in the squall line, resulting in smaller mass-weighted mean diameter (Dm) and larger generalized intercept parameter Nw of the empirical relation method and the small-particle-trace method retrieval. For weak convective precipitation at the back of the squall line, the value of empirical relation method is quite close to Parsivel disdrometer. Under different rain rate, μ value of C-FMCW radar is less than 10 and the fluctuation is smaller, indicating that the results of C-FMCW radar is even more reliable than Parsivel disdrometer and micro rain radar.
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图 1 2016年5月15日飑线后部弱对流降水观测及反演结果
(a)C-FMCW雷达反射率因子Ze, (b)经验关系法反演的大气垂直速度Va, (c)示踪法反演的大气垂直速度Va, (d)经验关系法反演的粒子群平均下落末速度Vt, (e)示踪法反演的粒子群平均下落末速度Vt, (f)雨滴谱仪观测的雨滴谱和雨强R
Fig. 1 Weak convective precipitation after the squall line passing on 15 May 2016
(a)C-FMCW reflectivity factor(Ze), (b)air vertical velocity(Va) retrieved by the empirical relation method, (c)air vertical velocity retrieved(Va) by the small-particle-trace method, (d)mean particle falling velocity(Vt) retrieved by the empirical relation method, (e)mean particle falling velocity(Vt) retrieved by the small-particle-trace method, (f)droplet size distribution and rain rate(R) measured by disdrometer
图 2 2016年5月15日不同雨强下的平均雨滴谱
(a)0<R≤0.2 mm·h-1，(b)0.2<R≤1 mm·h-1，(c)R>1 mm·h-1
Fig. 2 Mean droplet size distribution under three rain rate conditions on 15 May 2016
(a)0<R≤0.2 mm·h-1, (b)0.2<R≤1 mm·h-1, (c)R>1 mm·h-1
图 3 2016年5月15日19:43—21:20 3个设备物理量对比
Fig. 3 Comparison of physical parameters for three instruments from 1943 BT to 2120 BT on 15 May 2016
图 4 2016年5月6日飑线过境强对流降水观测及反演结果
(a)C-FMCW雷达的反射率因子Ze，(b)经验关系法反演的大气垂直速度Va，(c)示踪法反演的大气垂直速度Va，(d)经验关系法反演的粒子群平均下落末速度Vt，(e)示踪法反演的粒子群平均下落末速度Vt，(f)雨滴谱仪观测的雨滴谱和雨强R
Fig. 4 Strong convective precipitation of the squall line passing on 6 May 2016
(a)C-FMCW reflectivity factor(Ze), (b)air vertical velocity(Va) retrieved by the empirical relation method, (c)air vertical velocity(Va) retrieved by the small-particle-trace method, (d)mean particle falling velocity(Vt) retrieved by the empirical relation method, (e)mean particle falling velocity(Vt) retrieved by the small-particle-trace method, (f)droplet size distribution and rain rate(R) measured by disdrometer
图 5 2016年5月6日不同雨强下的平均雨滴谱
(a)0<R≤1 mm·h-1，(b)1<R≤10 mm·h-1，(c)R>10 mm·h-1
Fig. 5 Mean droplet size distribution under three rain rate conditions on 6 May 2016
(a)0<R≤1 mm·h-1, (b)1<R≤10 mm·h-1, (c)R>10 mm·h-1
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[1] Waldteufel P, Corbin H. On the analysis of single-Doppler radar data.J Appl Meteor Climatol,1979,18(4):532-542. doi: 10.1175/1520-0450(1979)018<0532:OTAOSD>2.0.CO;2 [2] 李渝, 马舒庆, 杨玲, 等. 长沙机场阵列天气雷达风场验证. 应用气象学报, 2020, 31(6): 681-693. doi: 10.11898/1001-7313.20200604Li Y, Ma S Q, Yang L, et al. Wind field verification for array weather radar at Changsha Airport. J Appl Meteor Sci, 2020, 31(6): 681-693. doi: 10.11898/1001-7313.20200604 [3] 管理, 戴建华, 陶岚, 等. QVP方法在双偏振雷达冬季降水观测中的应用. 应用气象学报, 2021, 32(1): 91-101. doi: 10.11898/1001-7313.20210108Guan L, Dai J H, Tao L, et al. Application of QVP method to winter precipitation observation. J Appl Meteor Sci, 2021, 32(1): 91-101. doi: 10.11898/1001-7313.20210108 [4] 林晓萌, 尉英华, 陈宏, 等. 降水时风廓线雷达风场反演效果评估. 应用气象学报, 2020, 31(3): 361-372. doi: 10.11898/1001-7313.20200310Lin X M, Wei Y H, Chen H, et al. The effect assessment of wind field inversion based on WPR in precipitation. J Appl Meteor Sci, 2020, 31(3): 361-372. doi: 10.11898/1001-7313.20200310 [5] Stokes G M, Schwartz S E. The Atmospheric Radiation Measurement(ARM) program: Programmatic background and design of the cloud and radiation test bed. Bull Amer Meteor Soc, 1994, 75(7): 1201-1222. doi: 10.1175/1520-0477(1994)075<1201:TARMPP>2.0.CO;2 [6] 阮征. 基于雷达资料的降水云微物理参数反演及垂直结构研究. 南京: 南京信息工程大学, 2015.Ruan Z. Microphysical Characteristics and Vertical Structure of Precipitation from Radar Observations. Nanjing: Nanjing University of Information Science & Technology, 2015. [7] Gossard E E, Strauch R O, Rogers R R. Evolution of dropsize distributions in liquid precipitation observed by ground-based Doppler radar. J Atmos Ocean Technol, 1990, 7(6): 815-828. doi: 10.1175/1520-0426(1990)007<0815:EODDIL>2.0.CO;2 [8] Shupe M D, Intrieri J M. Cloud radiative forcing of the arctic surface: The influence of cloud properties, surface albedo, and solar zenith angle. J Climate, 2004, 17(3): 616-628. doi: 10.1175/1520-0442(2004)017<0616:CRFOTA>2.0.CO;2 [9] Zheng J F, Liu L P, Zhu K Y, et al. A method for retrieving vertical air velocities in convective clouds over the Tibetan Plateau from TIPEX-III cloud radar Doppler spectra. Remote Sensing, 2017, 9(9): 964. doi: 10.3390/rs9090964 [10] Cui Y, Ruan Z, Wei M, et al. Vertical structure and dynamical properties during snow events in middle latitudes of China from observations by the C-band vertically pointing radar. J Meteor Soc Japan Ser II, 2020, 98(3): 527-550. doi: 10.2151/jmsj.2020-028 [11] Ma N K, Liu L P, Chen Y C, et al. Analysis of the vertical air motions and raindrop size distribution retrievals of a squall line based on cloud radar Doppler spectral density data. Atmosphere, 2021, 12(3): 348. doi: 10.3390/atmos12030348 [12] 霍朝阳. 基于C波段调频连续波垂直指向雷达的华南夏季降水云垂直结构特征及降水微物理研究. 南京: 南京信息工程大学, 2019.Huo Z Y. The Vertical Structural of Precipitation Cloud and Microphysics of Precipitation in South China Summer Based on the VPR-CFMCW. Nanjing: Nanjing University of Information Science & Technology, 2019. [13] 金龙, 阮征, 葛润生, 等. C-FMCW雷达对江淮降水云零度层亮带探测研究. 应用气象学报, 2016, 27(3): 312-322. doi: 10.11898/1001-7313.20160306Jin L, Ruan Z, Ge R S, et al. Bright band analysis in Yangtze-Huaihe Region of Anhui using data detection from C-FMCW radar. J Appl Meteor Sci, 2016, 27(3): 312-322. doi: 10.11898/1001-7313.20160306 [14] 阮征, 金龙, 葛润生, 等. C波段调频连续波天气雷达探测系统及观测试验. 气象学报, 2015, 73(3): 577-592. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB201503014.htmRuan Z, Jin L, Ge R S, et al. The C-band FMCW pointing weather radar system and its observation experiment. Acta Meteor Sinica, 2015, 73(3): 577-592. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB201503014.htm [15] 宋灿, 周毓荃, 吴志会. 雨滴谱垂直演变特征的微雨雷达观测研究. 应用气象学报, 2019, 30(4): 479-490. doi: 10.11898/1001-7313.20190408Song C, Zhou Y Q, Wu Z H, et al. Vertical profiles of raindrop size distribution observed by micro rain radar. J Appl Meteor Sci, 2019, 30(4): 479-490. doi: 10.11898/1001-7313.20190408 [16] Peters G, Fischer B, Andersson T. Rain observations with a vertically looking micro rain radar(MRR). Boreal Environment Research, 2002, 7(4): 353-362. [17] Loöffler-Mang M, Joss J. An optical disdrometer for measuring size and velocity of hydrometeors. J Atmos Ocean Technol, 2000, 17(2): 130-139. doi: 10.1175/1520-0426(2000)017<0130:AODFMS>2.0.CO;2 [18] 曾正茂, 郑佳锋, 杨晖, 等. Ka波段云雷达非云回波质量控制及效果评估. 应用气象学报, 2021, 32(3): 347-357. doi: 10.11898/1001-7313.20210307Zeng Z M, Zheng J F, Yang H, et al. Quality control and evaluation on non-cloud echo of Ka-band cloud radar. J Appl Meteor Sci, 2021, 32(3): 347-357. doi: 10.11898/1001-7313.20210307 [19] Monique P, Amadou S, Garrouste A, et al. Statistical characteristics of the noise power spectral density in UHF and VHF wind profilers. Radio Science, 1997, 32(3): 1229-1247. doi: 10.1029/97RS00250 [20] 郑佳锋. Ka波段-多模式亳米波雷达功率谱数椐处理方法及云内大气垂直速度反演研究. 南京: 南京信息工程大学, 2016.Zheng J F. Doppler Spectral Data Proccessing Methods of Ka-band Multi-mode mm-wave Radar and Air Vertical Speed Retrieval in Clouds. Nanjing: Nanjing University of Information Science & Technology, 2016. [21] Gunn R, Kinzer G D. The terminal velocity of fall for water droplets in stagnant air. J Atmos Sci, 1949, 6(4): 243-248. [22] Foote G B, Du Toit P S. Terminal velocity of raindrops aloft. J Appl Meteor, 1969, 8(2): 249-253. doi: 10.1175/1520-0450(1969)008<0249:TVORA>2.0.CO;2 [23] 马宁堃. 利用Ka波段毫米波雷达功率谱反演云降水大气垂直速度和雨滴谱分布研究. 北京: 中国气象科学研究院, 2019.Ma N K. Application of Doppler Spectral Density Data in Vertical Air Motions and Drop Size Distribution Retrieval in Cloud and Precipitation by Ka-band. Beijing: Chinese Academy of Meteorological Sciences, 2019. [24] 董佳阳, 崔晔, 阮征, 等. 对流降水云中大气垂直运动反演及个例试验. 应用气象学报, 2022, 33(2): 167-179. doi: 10.11898/1001-7313.20220204Dong J Y, Cui Y, Ruan Z, et al. Retrieval and experiments of atmospheric vertical motions in convective precipitation clouds. J Appl Meteor Sci, 2022, 33(2): 167-179. doi: 10.11898/1001-7313.20220204 [25] 金棋, 袁野, 纪雷, 等. 安徽滁州夏季―次飚线过程的雨滴谱特征. 应用气象学报, 2015, 26(6): 725-734. doi: 10.11898/1001-7313.20150609Jin Q, Yuan Y, Ji L, et al. Characteristics of raindrop size distribution for a squall line at Chuzhou of Anhui during summer. J Appl Meteor Sci, 2015, 26(6): 725-734. doi: 10.11898/1001-7313.20150609 [26] 王烁, 张佃国, 王文青, 等. 初冬一次层状云较弱云区垂直结构的飞机观测. 应用气象学报, 2021, 32(6): 677-690. doi: 10.11898/1001-7313.20210604Wang S, Zhang D G, Wang W Q, et al. Aircraft measurement of the vertical structure of a weak stratiform cloud in early winter. J Appl Meteor Sci, 2021, 32(6): 677-690. doi: 10.11898/1001-7313.20210604 -
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