Raindrop spectral characteristics and Z-R relationship of different rainstorm types in Huaibei region
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摘要: 选取2017—2020年淮北地区夏季雨滴谱观测资料对低槽型、副热带高压边缘型、冷涡影响型和台风型4种类型暴雨的雨滴谱进行分析。研究表明淮北地区降水主要以层状云为主,而对总降水贡献率大的却是对流云降水。不同类型暴雨微物理量同样存在差异,低槽型、台风型暴雨的粒子数浓度较大,副热带高压边缘型和冷涡影响型各种特征直径比其他两类大。分析不同尺度雨滴粒子与雨强的关系,小雨滴数浓度占比超过60%,但对雨强起主要贡献的是中粒子,不同类型暴雨的差异主要是由小雨滴和大雨滴对雨强贡献率的差异造成的;并且随着雨强的增大,小雨滴的贡献率逐渐降低,大雨滴增大。不同雨强档下的雨滴谱分布基本呈单峰型,随着雨强增大各尺度档粒子数浓度升高,谱宽增大,斜率逐渐减小;当雨强增大时质量平均直径(Dm)-标准化参数(lgNW)分布趋于集中,Dm和lgNW的平均值分别为1.15 mm和3.79 mm−1m−3;通过Γ分布拟合发现,低槽型和台风型暴雨谱分布参数的平均值和标准差大于另外两类;除标准化参数的偏度为负值外,其余各参数的偏度均为正值;不同类型暴雨谱型-斜率(µ-Λ)及反射率因子-雨强(Z-R)略有差异。研究得出的淮北地区暴雨Z-R关系为Z=164.4R1.42,相比之下,目前雷达系统采用的标准关系式低估了淮北地区暴雨降水量,尤其在评估低槽型和台风型暴雨时误差较大。Abstract: Based on observations of summer raindrop spectra in Huaibei region from 2017 to 2020, the raindrop spectrum distributions of four rainstorm types, i.e., the trough type, the subtropical high edge type, the cold vortex type and the typhoon type, are analyzed. Results show that the occurrence frequency of precipitation in Huaibei area is dominated by stratiform precipitation, while convective precipitation is the main contributor to total precipitation. The microphysical parameters of different types of rainstorms are also different. The number concentration of low trough type and typhoon type is larger than that of other types, and the characteristic diameters of subtropical high edge type and cold vortex type are larger than those of the other two types. The relationship between raindrop particles and rain intensity at different scales is analyzed. It is found that small raindrops account for more than 60% of the number concentration, yet medium raindrops make a major contribution to rain intensity. The differences between different types of rainstorm are mainly caused by differences in the contribution rates of small raindrops and heavy raindrops to rainfall intensity. And with the increase of precipitation intensity, the contribution rate of small raindrops decreases, while that of large raindrops increases. The distribution of raindrop spectrum under different rain intensity classes is basically unimodal. With the increase of rain intensity, the number concentrations of various particles increase, the spectral width increases and the slope decreases. When the rain intensity increases, the mass-weighted mean diameter (Dm)-normalized intercept parameter (lgNW) distribution tends to be concentrated, and the mean values of Dm and lgNW are 1.15 mm and 3.79 mm−1m−3, respectively. Through Gamma distribution fitting, it is found that the mean values and standard deviations of spectral distribution parameters of low trough type and typhoon type are greater than those of the other two types. The skewness of all parameters is positive except that of the parameters (lgNW), which is negative. The shape parameter-slope parameter (µ-Λ) and radar reflectivity factor-radar reflectivity factor (Z-R) are slightly different between different types of rainstorm. In this paper, total precipitation in Huaibei area is calculated by Z=164.4R1.42. In contrast, the standard relationship adopted by radar system at present underestimates rainstorm precipitation in Huaibei area, especially for low trough type rainstorms and typhoon type rainstorms.
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图 3 观测得到的雨滴尺度-速度谱分布 (色阶代表对数尺度的雨滴数,红色*代表实测平均加权速度,蓝色实线表示Atlas等 (1973) 雨滴末速度拟合曲线,黑色实线是下落速度的拟合曲线) 和各尺度档的箱线图 (a. 低槽型,b. 副热带高压边缘型,c. 冷涡影响型,d. 台风型)
Figure 3. Occurrence of velocity-diameter combinations (color shading represents drop counts on a log scale,red star represents measured average weighted velocity,solid black line shows the fitting curve of falling velocity,and the blue line indicates the Atlas,et al (1973) terminal drop velocity) and the box plot of each raindrop size classes (a. Type 1,b. Type 2,c. Type 3,d. Type 4)
图 4 不同类型暴雨 (a. 低槽型,b. 副热带高压边缘型,c. 冷涡影响型,d. 台风型) 雨滴谱时间序列 (色阶为数浓度N(Di),单位:mm−1m−3;黑色点线为质量平均直径,红色实线代表雨强)
Figure 4. Time series of DSDs for (a. Type 1,b. Type 2,c. Type 3,d. Type 4) different types of rainstorm (the shadings represent DSD,unit:mm−1m−3;the black dotted line is the mass-weighted mean diameter,and the red solid line is the rainfall rate)
图 10 不同类型暴雨的 (a1—d1) 雨滴数浓度 (NT) 与体积中值直径 (D0)、(a2—d2) 雨滴数浓度 (lgNT) 和质量平均直径 (Dm)、(a3—d3) 标准化参数 (lgNW) 和质量平均直径 (Dm)(黑色实线与虚线方框分别代表海洋性和大陆性对流区域)、(a4—d4) 标准化参数 (lgNW) 和雨滴数浓度 (lgNT)( c 为两者相关系数) 散点 (a. 低槽型,b. 副热带高压边缘型,c. 冷涡影响型,d. 台风型)
Figure 10. Scatter plots of (a1—d1)raindrop concentration (NT) and the volume median diameter (D0),(a2—d2) raindrop concentration (lgNT) and mass-weighted mean diameter (Dm),(a3—d3) normalized intercept parameter (lgNW) and mass-weighted mean diameter (Dm)(the solid and dotted black lines represent the maritime and continental convective regions,respectively),(a4—d4) normalized intercept parameter (lgNW) and raindrops concentration (lgNT)("c" represents correlation coefficient between them) for different types of rainstorm (a. Type 1,b. Type 2,c. Type 3,d. Type 4)
图 11 不同类型暴雨 (a. 低槽型,b. 副热带高压边缘型,c. 冷涡影响型,d. 台风型) 各参数与雨强的关系 (a1—d1. Dm与R,a2—d2. lgNT与R, a3—d3. lgNW与R (红色实线为使用最小二乘法的拟合曲线,蓝色实线为R≥60 mm/h时拟合曲线,并提供了拟合关系和相关系数),a4—d4. Γ分布参数 (lgN0(单位:mm−1−µ·m−3)、 μ(无量纲)、Λ(单位:mm−1)与R)
Figure 11. Relationships between various parameters and rainfall rate of different types of rainstorm (a. Type 1,b. Type 2,c. Type 3,d. Type 4; a1—d1,a2—d2,a3—d3 correspond to relationships of Dm,lgNT,lgNW with R (the red solid line is the fitting curve using the least square method,and the blue solid line is the fitting curve when the rain rate is more than 60 mm/h,and the fitting relationship and correlation coefficient are provided); a4—d4 show relationships between parameters of Γ-distribution (lgN0(unit:mm−1−µ·m−3),μ(dimensionless),Λ(unit:mm−1) and R)
图 12 不同类型暴雨 (a. 低槽型,b. 副热带高压边缘型,c. 冷涡影响型,d. 台风型) 和总样本 (e) 的 μ-Λ关系 (蓝色圆圈为过滤后数据,灰色叉号为未过滤的数据,红色实线是过滤后数据的拟合曲线,黑色实线为Zhang等 (2003) 和Chen等 (2013) 经验μ-Λ关系,虚线对应Dm=(4+μ)/Λ中Dm=0.5、1、2、3 mm)
Figure 12. Relationship of μ-Λ of different types of rainstorm (a. Type 1,b. Type 2,c. Type 3,d. Type 4) and total sample (e) (blue circles represent the data after filtering while gray crosses represent the data without filtering;the red and black solid lines represent the fitting of data after filtering and the empirical μ-Λ relationship from Zhang,et al (2003) and Chen,et al (2013);the dashed lines correspond to the relationship Dm=(4+μ)/Λ given the value of Dm=0.5,1,2,3 mm)
图 13 不同类型暴雨 (a. 低槽型,b. 副热带高压边缘型,c. 冷涡影响型,d. 台风型) 和总样本 (e) 的Z-R散点分布 (蓝色圆圈为过滤后数据,灰色叉号为未过滤数据,紫色点线为未过滤数据拟合曲线,红色实线为过滤后数据拟合曲线,黑色实线为Fulton等 (1998) 经验Z-R关系)
Figure 13. Scatter plots of Z-R of different types of rainstorm (a. Type 1,b. Type 2,c. Type 3,d. Type 4) and total sample (e) (blue circles represent the data after filtering while the gray crosses represent the data without filtering,the red solid line is the fitting curve of filtered data,the purple dotted line is the fitting curve of unfiltered data,and the black solid line represents the empirical relationship from Fulton,et al (1998))
表 1 雨滴谱微物理特征量的含义和计算公式
Table 1. Definition and calculation formula of microphysical characteristics of raindrop spectrum
特征量 符号 单位 定义 公式 数浓度 NT m−3 单位空间的雨滴总量 $\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } {N(D)} \text{d}D$ 雨强 R mm/h 单位时间的降水量 $\dfrac{ {6{\text π} } }{ { { {10}^4} } }\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } { {D^3}N(D)} V(D)\text{d}D$ 雨水含量 W g/m3 单位空间雨滴总质量 $\dfrac{ { {\text π}{\rho_{ {}_{{\text{w} } } } } } }{ {6000} }\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } { {D^3}N(D)} \text{d}D$ 反射率因子 Z mm6m−3 降水回波强度 $\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } { {D^6}N(D)} \text{d}D$ 算术平均直径 Da mm 全部雨滴的直径总和除以雨滴的总数 ${ {\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } {DN(D)} \text{d}D} \mathord{\left/ {\vphantom { {\int_{ {D_{\min } } }^{ {D_{\max } } } {DN(D)} \text{d}D} {\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } {N(D)} \text{d}D} } } \right. } {\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } {N(D)} \text{d}D} }$ 质量平均直径 Dm mm 单位体积内所有粒子直径加权质量相对于粒子总质
量的平均直径${\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } { {D^4}N(D)} \text{d}D} \Bigg/ {\displaystyle\int_{ {D_{\min } } }^{ {D_{\max } } } { {D^3}N(D)} \text{d}D}$ 体积中值直径 D0 mm 含水量的一半是由半径大于此值的大雨滴所组成的 ${\displaystyle\int_{ {D_{\min } } }^{ {D_0} } { {D^3}N(D)} \text{d}D} \Bigg/ {\displaystyle\int_{ {D_0} }^{ {D_{\max } } } { {D^3}N(D)} \text{d}D}$ 峰值直径 Dp mm 最大频率直径 $ N(D) $最大值所对应的直径 粒子谱宽 Dw mm 粒子最大直径和最小直径差 $ {D_{\max }} - {D_{\min }} $ 表 2 2017—2020年徐州23次区域性暴雨天气过程简况
Table 2. Synopsis of 23 regional rainstorms in Xuzhou from 2017 to 2020
日期 暴雨站 暴雨天气类型 2017年7月5—7日 丰县、沛县、徐州、邳州、新沂、睢宁 低槽型 2017年7月13—15日 丰县、沛县、徐州、邳州、新沂 低槽型 2017年7月30日—8月3日 徐州、邳州、新沂、睢宁 台风型 2017年8月18—20日 新沂、睢宁 低槽型 2018年7月8日 徐州、邳州、睢宁 低槽型 2018年7月26—28日 睢宁 副热带高压边缘型 2018年7月28—31日 丰县、沛县、徐州 副热带高压边缘型 2018年8月13—15日 丰县、沛县、徐州、邳州、新沂、睢宁 台风型 2018年8月17—19日 丰县、沛县、徐州、邳州、新沂、睢宁 台风型 2019年6月6—7日 新沂、睢宁 冷涡影响型 2019年6月28—29日 新沂 冷涡影响型 2019年7月6日 睢宁 冷涡影响型 2019年7月23—25日 徐州 副热带高压边缘型 2019年7月27—28日 丰县、徐州、睢宁 副热带高压边缘型 2019年8月1—2日 丰县、沛县 副热带高压边缘型 2019年8月10—11日 丰县、沛县、徐州、邳州、新沂、睢宁 台风型 2020年6月11—13日 徐州、邳州、新沂、睢宁 低槽型 2020年6月15—18日 徐州、邳州、新沂、睢宁 低槽型 2020年6月28—30日 新沂、睢宁 低槽型 2020年7月11—13日 丰县、沛县、徐州、邳州、新沂、睢宁 低槽型 2020年7月31日—8月1日 睢宁 副热带高压边缘型 2020年8月6—7日 丰县、沛县、徐州 副热带高压边缘型 2020年8月19—21日 新沂 副热带高压边缘型 表 3 不同类型暴雨雨滴谱微物理特征量的平均值
Table 3. Mean values of microphysical characteristics of raindrop spectra for different rainstorm types
暴雨类型 NT(m−3) R(mm/h) W(g/m3) 特征直径(mm) Da Dm D0 Dp Dw 低槽型 558.18 4.24 0.25 0.794 1.116 1.100 0.652 1.528 副热带高压边缘型 359.19 5.22 0.28 0.900 1.328 1.310 0.718 1.810 冷涡影响型 419.56 5.81 0.33 0.894 1.313 1.284 0.708 1.894 台风型 481.49 4.27 0.24 0.817 1.116 1.100 0.690 1.492 综合 492.20 4.43 0.26 0.822 1.153 1.137 0.679 1.564 -
陈磊,陈宝君,杨军等. 2013. 2009—2010年梅雨锋暴雨雨滴谱特征. 大气科学学报,36(4):481-488 doi: 10.3969/j.issn.1674-7097.2013.04.011Chen L,Chen B J,Yang J,et al. 2013. Characteristics of raindrop size distribution of rainstorm on Meiyu front during 2009-2010. Trans Atmos Sci,36(4):481-488 (in Chinese) doi: 10.3969/j.issn.1674-7097.2013.04.011 陈子健,胡向峰,陈宝君等. 2019. 河北省中南部暴雨雨滴谱特征. 干旱气象,37(4):586-596Chen Z J,Hu X F,Chen B J,et al. 2019. Raindrop size distribution of rainstorm in central-southern Hebei province. J Arid Meteor,37(4):586-596 (in Chinese) 丁一汇. 2019. 中国暴雨理论的发展历程与重要进展. 暴雨灾害,38(5):395-406Ding Y H. 2019. The major advances and development process of the theory of heavy rainfalls in China. Torrential Rain Disaster,38(5):395-406 (in Chinese) 江苏省气象局. 2017. 江苏省天气预报技术手册. 北京:气象出版社,60-85Jiangsu Meteorological Bureau. 2017. Weather Forecast Technical Manual of Jiangsu Province. Beijing:China Meteorological Press,60-85 (in Chinese) 金祺,袁野,刘慧娟等. 2015. 江淮之间夏季雨滴谱特征分析. 气象学报,73(4):778-788 doi: 10.11676/qxxb2015.036Jin Q,Yuan Y,Liu H J,et al. 2015. Analysis of microphysical characteristics of the raindrop spectrum over the area between the Yangtze river and the Huaihe river during summer. Acta Meteor Sinica,73(4):778-788 (in Chinese) doi: 10.11676/qxxb2015.036 李慧,银燕,单云鹏等. 2018. 黄山层状云和对流云降水不同高度的雨滴谱统计特征分析. 大气科学,42(2):268-280Li H,Yin Y,Shan Y P,et al. 2018. Statistical characteristics of raindrop size distribution for stratiform and convective precipitation at different altitudes in Mt. Huangshan. Chinese J Atmos Sci,42(2):268-280 (in Chinese) 罗亚丽,孙继松,李英等. 2020. 中国暴雨的科学与预报:改革开放40年研究成果. 气象学报,78(3):419-450 doi: 10.11676/qxxb2020.057Luo Y L,Sun J S,Li Y,et al. 2020. Science and prediction of heavy rainfall over China:Research progress since the reform and opening-up of the People's Republic of China. Acta Meteor Sinica,78(3):419-450 (in Chinese) doi: 10.11676/qxxb2020.057 梅海霞,郭文刚,周林义等. 2017. 雨滴谱谱形参数对梅雨降水模拟能力的影响. 气象,43(1):34-45 doi: 10.7519/j.issn.1000-0526.2017.01.004Mei H X,Guo W G,Zhou L Y,et al. 2017. Effect of shape parameter of raindrop spectrum on the simulation of Meiyu rainfall. Meteor Mon,43(1):34-45 (in Chinese) doi: 10.7519/j.issn.1000-0526.2017.01.004 梅海霞,梁信忠,曾明剑等. 2020. 2015—2017年夏季南京雨滴谱特征. 应用气象学报,31(1):117-128 doi: 10.11898/1001-7313.20200111Mei H X,Liang X Z,Zeng M J,et al. 2020. Raindrop size distribution characteristics of Nanjing in Summer of 2015-2017. J Appl Meteor Sci,31(1):117-128 (in Chinese) doi: 10.11898/1001-7313.20200111 王俊,姚展予,侯淑梅等. 2016. 一次飑线过程的雨滴谱特征研究. 气象学报,74(3):450-464 doi: 10.11676/qxxb2016.034Wang J,Yao Z Y,Hou S M,et al. 2016. Characteristics of the raindrop size distribution in a squall line measured by Thies optical disdrometers. Acta Meteor Sinica,74(3):450-464 (in Chinese) doi: 10.11676/qxxb2016.034 张鹏,刘西川,周则明等. 2021. 基于实测雨滴谱数据的微波链路和天气雷达降水估计关系研究. 气象,47(7):843-853 doi: 10.7519/j.issn.1000-0526.2021.07.007Zhang P,Liu X C,Zhou Z M,et al. 2021. Research on precipitation estimators of microwave link and weather radar based on raindrop size distribution data. Meteor Mon,47(7):843-853 (in Chinese) doi: 10.7519/j.issn.1000-0526.2021.07.007 赵城城,张乐坚,梁海河等. 2021. 北京山区和平原地区夏季雨滴谱特征分析. 气象,47(7):830-842 doi: 10.7519/j.issn.1000-0526.2021.07.006Zhao C C,Zhang L J,Liang H H,et al. 2021. Microphypical characteristics of the raindrop size distribution between mountain and plain areas over Beijing in summer. Meteor Mon,47(7):830-842 (in Chinese) doi: 10.7519/j.issn.1000-0526.2021.07.006 周黎明,王庆,龚佃利等. 2015. 山东一次暴雨过程的云降水微物理特征分析. 气象,41(2):192-199 doi: 10.7519/j.issn.1000-0526.2015.02.007Zhou L M,Wang Q,Gong D L,et al. 2015. Microphysical properties of cloud and precipitation during a rainstorm process in Shandong province. Meteor Mon,41(2):192-199 (in Chinese) doi: 10.7519/j.issn.1000-0526.2015.02.007 周黎明,王庆,李芳. 2017. 山东不同天气系统下暴雨雨滴谱特征分析. 自然灾害学报,26(6):217-223Zhou L M,Wang Q,Li F. 2017. Analysis on characteristics of raindrop size distribution of rainstorm under different weather system in Shandong province. J Nat Dis,26(6):217-223 (in Chinese) 朱红芳,杨祖祥,王东勇等. 2019. 进入内陆的两个台风降水特征对比分析. 气象学报,77(2):268-281 doi: 10.11676/qxxb2019.011Zhu H F,Yang Z X,Wang D Y,et al. 2019. Comparative analysis of the rainstorms caused by two typhoons in inland China. Acta Meteor Sinica,77(2):268-281 (in Chinese) doi: 10.11676/qxxb2019.011 Atlas D,Srivastava R C,Sekhon R S. 1973. Doppler radar characteristics of precipitation at vertical incidence. Rev Geophys,11(1):1-35 doi: 10.1029/RG011i001p00001 Battaglia A,Rustemeier E,Tokay A,et al. 2010. PARSIVEL snow observations:A critical assessment. J Atmos Ocean Technol,27(2):333-344 doi: 10.1175/2009JTECHA1332.1 Bringi V N,Chandrasekar V,Hubbert J,et al. 2003. Raindrop size distribution in different climatic regimes from disdrometer and dual-polarized radar analysis. J Atmos Sci,60(2):354-365 doi: 10.1175/1520-0469(2003)060<0354:RSDIDC>2.0.CO;2 Cao Q,Zhang G F. 2009. Errors in estimating raindrop size distribution parameters employing disdrometer and simulated raindrop spectra. J Appl Meteor Climatol,48(2):406-425 doi: 10.1175/2008JAMC2026.1 Chen B J,Wang Y,Ming J. 2012. Microphysical characteristics of the raindrop size distribution in typhoon Morakot (2009). J Trop Meteor,18(2):162-171 Chen B J,Yang J,Pu J P. 2013. Statistical characteristics of raindrop size distribution in the Meiyu season observed in Eastern China. J Meteor Soc Japan,91(2):215-227 doi: 10.2151/jmsj.2013-208 Chen B J,Hu Z Q,Liu L P,et al. 2017. Raindrop size distribution measurements at 4500 m on the Tibetan Plateau during TIPEX-Ⅲ. J Geophys Res:Atmos,122(20):11092-11106 doi: 10.1002/2017JD027233 Chen Y,Duan J,An J L,et al. 2019. Raindrop size distribution characteristics for tropical cyclones and Meiyu-Baiu fronts impacting Tokyo,Japan. Atmosphere,10(7):391 doi: 10.3390/atmos10070391 Das S K,Konwar M,Chakravarty K,et al. 2017. Raindrop size distribution of different cloud types over the Western Ghats using simultaneous measurements from Micro-Rain Radar and disdrometer. Atmos Res,186:72-82 doi: 10.1016/j.atmosres.2016.11.003 De Moraes Frasson R P,Da Cunha L K,Krajewski W F. 2011. Assessment of the Thies optical disdrometer performance. Atmos Res,101:237-255 doi: 10.1016/j.atmosres.2011.02.014 Fulton R A,Breidenbach J P,Seo D J,et al. 1998. The WSR-88D rainfall algorithm. Wea Forecasting,13(2):377-395 doi: 10.1175/1520-0434(1998)013<0377:TWRA>2.0.CO;2 Geoffroy O,Siebesma A P,Burnet F. 2014. Characteristics of the raindrop distributions in RICO shallow cumulus. Atmos Chem Phys,14(19):10897-10909 doi: 10.5194/acp-14-10897-2014 Han Y,Guo J P,Yun Y X,et al. 2021. Regional variability of summertime raindrop size distribution from a network of disdrometers in Beijing. Atmos Res,257:105591 doi: 10.1016/j.atmosres.2021.105591 Hou T J,Lei H C,Hu Z X,et al. 2020. Simulations of microphysics and precipitation in a stratiform cloud case over northern China:Comparison of two microphysics schemes. Adv Atmos Sci,37(1):117-129 doi: 10.1007/s00376-019-8257-0 Hu Z,Srivastava R C. 1995. Evolution of raindrop size distribution by coalescence,breakup,and evaporation:Theory and observations. J Atmos Sci,52(10):1761-1783 doi: 10.1175/1520-0469(1995)052<1761:EORSDB>2.0.CO;2 Huo Z Y,Ruan Z,Wei M,et al. 2019. Statistical characteristics of raindrop size distribution in south China summer based on the vertical structure derived from VPR-CFMCW. Atmos Res,222:47-61 doi: 10.1016/j.atmosres.2019.01.022 Luo L,Xiao H,Yang H L,et al. 2020. Raindrop size distribution and microphysical characteristics of a great rainstorm in 2016 in Beijing,China. Atmos Res,239:104895 doi: 10.1016/j.atmosres.2020.104895 Lv J,Jiang Z H,Peng H Q,et al. 2012. New definition for north Huaihe river rainy season and atmospheric circulation characteristics in precipitation anomaly years. J Trop Meteor,18(4):521-527 Ma N K,Liu L P,Chen Y C,et al. 2021. Analysis of the vertical air motions and raindrop size distribution retrievals of a squall line based on cloud radar Doppler spectral density data. Atmosphere,12(3):348 doi: 10.3390/atmos12030348 Marzano F S,Cimini D,Montopoli M. 2010. Investigating precipitation microphysics using ground-based microwave remote sensors and disdrometer data. Atmos Res,97(4):583-600 doi: 10.1016/j.atmosres.2010.03.019 Montero-Martínez G,Kostinski A B,Shaw R A,et al. 2009. Do all raindrops fall at terminal speed?. Geophys Res Lett,36(11):L11818 doi: 10.1029/2008GL037111 Niu S J,Jia X C,Sang J R,et al. 2010. Distributions of raindrop sizes and fall velocities in a semiarid plateau climate:Convective versus stratiform rains. J Appl Meteor Climatol,49(4):632-645 doi: 10.1175/2009JAMC2208.1 Rosenfeld D,Ulbrich C W. 2003. Cloud microphysical properties,processes,and rainfall estimation opportunities. Meteor Monogr,30(52):237-258 doi: 10.1175/0065-9401(2003)030<0237:CMPPAR>2.0.CO;2 Testud J,Oury S,Black R A,et al. 2001. The concept of "normalized" distribution to describe raindrop spectra:A tool for cloud physics and cloud remote sensing. J Appl Meteor Climatol,40(6):1118-1140 doi: 10.1175/1520-0450(2001)040<1118:TCONDT>2.0.CO;2 Tokay A,Bashor P G,Habib E,et al. 2008. Raindrop size distribution measurements in tropical cyclones. Mon Wea Rev,136(5):1669-1685 doi: 10.1175/2007MWR2122.1 Tokay A,Bashor P G. 2010. An experimental study of small-scale variability of raindrop size distribution. J Appl Meteor Climatol,49(11):2348-2365 doi: 10.1175/2010JAMC2269.1 Ulbrich C W. 1983. Natural variations in the analytical form of the raindrop size distribution. J Appl Meteor Climatol,22(10):1764-1775 doi: 10.1175/1520-0450(1983)022<1764:NVITAF>2.0.CO;2 Ulbrich C W,Atlas D. 2007. Microphysics of raindrop size spectra:Tropical continental and maritime storms. J Appl Meteor Climatol,46(11):1777-1791 doi: 10.1175/2007JAMC1649.1 Wang G L,Zhou R R,Zhaxi S L,et al. 2021. Raindrop size distribution measurements on the Southeast Tibetan Plateau during the STEP project. Atmos Res,249:105311 doi: 10.1016/j.atmosres.2020.105311 Wang H,Wang W Q,Wang J,et al. 2021. Rainfall microphysical properties of landfalling Typhoon Yagi (201814) based on the observations of micro rain radar and cloud radar in Shandong,China. Adv Atmos Sci,38(6):994-1011 doi: 10.1007/s00376-021-0062-x Wang M J,Zhao K,Xue M,et al. 2016. Precipitation microphysics characteristics of a typhoon Matmo (2014) rainband after landfall over eastern China based on polarimetric radar observations. J Geophys Res,121(20):12415-12433 doi: 10.1002/2016JD025307 Wen L,Zhao K,Zhang G F,et al. 2016. Statistical characteristics of raindrop size distributions observed in east China during the Asian Summer monsoon season using 2-D video Disdrometer and micro rain radar data. J Geophys Res:Atmos,121(5):2265-2282 doi: 10.1002/2015JD024160 Wen L,Zhao K,Chen G,et al. 2018. Drop size distribution characteristics of seven typhoons in China. J Geophys Res:Atmos,123(12):6529-6548 doi: 10.1029/2017JD027950 Zhang G F,Vivekanandan J,Brandes E A,et al. 2003. The shape-slope relation in observed Gamma raindrop size distributions:Statistical error or useful information?. J Atmos Ocean Technol,20(8):1106-1119 doi: 10.1175/1520-0426(2003)020<1106:TSRIOG>2.0.CO;2 Zheng H P,Wu Z H,Zhang L F,et al. 2020. Improving radar rainfall estimations with scaled raindrop size spectra in Mei-Yu frontal rainstorms. Sensors,20(18):5257 doi: 10.3390/s20185257 -