一次华南超级单体风暴的S波段偏振雷达观测分析
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摘要
利用珠海与澳门共建的中国首部S波段业务双偏振雷达探测资料、风廓线资料和地面加密观测资料,对2015年4月20日发生在珠海附近的一次典型华南春季冷锋触发的超级单体风暴的偏振观测特征进行了分析。天气分析表明,风暴发生于地面冷锋和低空切变线附近,中等对流不稳定(对流有效位能为1300 J/kg)和较强风垂直切变(0—6 km风矢量差为20 m/s)环境中。环境总理查逊数为18,与中纬度典型超级单体的生成环境接近,风暴相对螺旋度为2.9 s~(-1)。偏振观测分析表明,大雹粒子的翻滚使冰雹区具有水平反射率因子高(>50 dBz)、差分反射率低(-1—0.5 dB)的特点;雨和冰相粒子的混合导致了相关系数的下降(小于0.9);比差分相位观测对冰雹并不敏感(比差分相位与水平反射率因子的线性拟合率仅为0.05)。在混合相粒子和液相粒子的共同作用下,融化层附近存在差分反射率增大、相关系数减小的现象。风暴侧前方下沉气流偏东侧边界(水平反射率因子梯度高值区)存在一条"差分反射率弧"(差分反射率高值区),主要由大雨滴构成,粒子分选机制合理解释了其形成原因。同时,相对较大的环境风使差分反射率弧更加远离(相对北美观测事实)风暴主体。风暴水平反射率因子中心附近存在"差分反射率柱",与大雨滴被上升气流(连续分布的正径向风)带入高层冻结且失去取向稳定而导致差分反射率值迅速减小有关。
The Zhu-Macao polarimetric radar data are used to analyze the structure and microphysics of a supercell near Zhuhai during 07:00-10:00 UTC20 April 2015(hereafter "4.20" supercell case).The storm occurred near the surface cold front and the low-level shear line,where the CAPE was 1300 J/kg and the wind shear between 0 and 6 km was greater than 20 m/s.The total Richardson number was 18,which is close to the value for typical mid-latitude supercell and the relative helicity of the storm was 2.9 s~(-1).A number of distinctive polarimetric signatures are found in the storm.The most remarkable signatures of hails were low differential reflectivity(ZDR)(-1 to 0.5 dB)and high reflectivity at horizontal polarizations(ZH)(>50 dBz).Because of tumbling,the ZDR of large hail area was close to 0.The cross-correlation coefficient(CC)was lower than 0.9 in the rain-hail mixtures and the hails had a negligible influence on the specific differential phase(KDP)(the slope of linear regression between ZH and KDP was 0.05).Because of the mixed phase particles and the liquid particles,a characteristic of enhanced ZDR and depressed CC was found near the updraft-perturbed melting layer.A shallow region of high ZDR(>3 dB)was found in the east edge of the forward-flank downdraft(FFD),called the " ZDR arc",which was associated with large,oblate raindrops.The size-sorting mechanism can explain this phenomenon.Compared to observations in North America,the higher environmental winds made the ZDR further away from the ZH center in the "4.20" supercell case.The ZDR columns were observed near the ZH center.The reason is that large raindrops were brought to the upper layer by updrafts and then losed orientation stability when they froze,thereby the ZDR values decreased significantly.
The Zhu-Macao polarimetric radar data are used to analyze the structure and microphysics of a supercell near Zhuhai during 07:00-10:00 UTC20 April 2015(hereafter "4.20" supercell case).The storm occurred near the surface cold front and the low-level shear line,where the CAPE was 1300 J/kg and the wind shear between 0 and 6 km was greater than 20 m/s.The total Richardson number was 18,which is close to the value for typical mid-latitude supercell and the relative helicity of the storm was 2.9 s~(-1).A number of distinctive polarimetric signatures are found in the storm.The most remarkable signatures of hails were low differential reflectivity(ZDR)(-1 to 0.5 dB)and high reflectivity at horizontal polarizations(ZH)(>50 dBz).Because of tumbling,the ZDR of large hail area was close to 0.The cross-correlation coefficient(CC)was lower than 0.9 in the rain-hail mixtures and the hails had a negligible influence on the specific differential phase(KDP)(the slope of linear regression between ZH and KDP was 0.05).Because of the mixed phase particles and the liquid particles,a characteristic of enhanced ZDR and depressed CC was found near the updraft-perturbed melting layer.A shallow region of high ZDR(>3 dB)was found in the east edge of the forward-flank downdraft(FFD),called the " ZDR arc",which was associated with large,oblate raindrops.The size-sorting mechanism can explain this phenomenon.Compared to observations in North America,the higher environmental winds made the ZDR further away from the ZH center in the "4.20" supercell case.The ZDR columns were observed near the ZH center.The reason is that large raindrops were brought to the upper layer by updrafts and then losed orientation stability when they froze,thereby the ZDR values decreased significantly.
引文
Bringi V N,Chandrasekar V.李忱,张越译.2010.偏振多普勒天气雷达原理和应用.北京:气象出版社,159-185.Bringi V N,Chandrasekar V.Li C,Zhang Y,trans.Polarimetric Doppler Weather Radar:Principles and Applications.Beijing:China Meteorological Press,159-185(in Chinese)
曹俊武,刘黎平,葛润生.2005.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,29(5):827-836.Cao J W,Liu L P,Ge R S.2005.A study of fuzzy logic method in classification of hydrometeors based on polarimetric radar measurement.Chinese J Atmos Sci,29(5):827-836(in Chinese)
刘黎平,钱永甫,王致君.1996.用双线偏振雷达研究云内粒子相态及尺度的空间分布.气象学报,54(5):590-599.Liu L P,Qian Y F,Wang Z J.1996.The study of spacial distribution of phase and size of hydrometeorsin cloud by dual linear polarization radar.Acta Meteor Sinica,54(5):590-599(in Chinese)
苏德斌,马建立,张蔷等.2011.X波段双线偏振雷达冰雹识别初步研究.气象,37(10):1228-1232.Su D B,Ma J L,Zhang Q,et al.2011.Preliminary research on method of hail detection with X band dual linear polarization radar.Meteor Mon,37(10):1228-1232(in Chinese)
孙丝雨,沈永海,霍苗等.2013.双线偏振雷达在一次强降雹过程中的初步应用.暴雨灾害,32(3):249-255.Sun S Y,Shen YH,Huo M,et al.2013.Preliminary application of dual-polarization weather radar in a severe hail event.Torrential Rain Disaster,32(3):249-255(in Chinese)
王福侠,俞小鼎,闫雪瑾.2014.一次超级单体分裂过程的雷达回波特征分析.气象学报,72(1):152-167.Wang F X,Yu X D,Yan X J.2014.Analysis of the splitting processes of the supercell storms based on the Doppler weather radar data.Acta Meteor Sinica,72(1):152-167(in Chinese)
俞小鼎,郑媛媛,张爱民等.2006.安徽一次强烈龙卷的多普勒天气雷达分析.高原气象,25(5):914-924.Yu X D,Zheng Y Y,Zhang A M,et al.2006.The detection of a severe tornado event in Anhui with China new generation weather radar.Plateau Meteor,25(5):914-924(in Chinese)
张鸿发,郄秀书,王致君等.2001.偏振雷达观测强对流雹暴云.大气科学,25(1):38-48.Zhang H F,Qie X S,Wang Z J,et al.2001.Polarization radar observations on hailstorms.Chinese JAtmos Sci,25(1):38-48(in Chinese)
赵坤,周仲岛,潘玉洁等.2008.台湾海峡中气旋结构特征的单多普勒雷达分析.气象学报,66(4):637-651.Zhao K,Zhou Z D,Pan Y J,et al.2008.Single-Doppler radar analysis of a mesocyclone in the Taiwan Strait.Acta Meteor Sinica,66(4):637-651(in Chinese)
郑媛媛,俞小鼎,方翀等.2004.一次典型超级单体风暴的多普勒天气雷达观测分析.气象学报,62(3):317-328.Zheng Y Y,Yu X D,Fang C,et al.2004.Analysis of a strong classic supercell storm with Doppler weather radar data.Acta Meteor Sinica,62(3):317-328(in Chinese)
Anderson M E,Carey L D,Petersen W A,et al.2011.C-band dual-polarimetric radar signatures of hail.Electronic J Operat Meteor,12(2):45-75
Aydin K,Seliga T A,Balaji V.1986.Remote sensing of hail with a dual linear polarization radar.J Climate Appl Meteor,25(10):1475-1484
Balakrishnan N,Zrnic D S.1990.Use of polarization to characterize precipitation and discriminate large hail.J Atmos Sci,47(13):1525-1540
Bluestein H B,French M M,Tanamachi R L,et al.2007.Closerange observations of tornadoes in supercells made with a dualpolarization,X-band,mobile Doppler radar.Mon Wea Rev,135(4):1522-1543
Bosart L F,Seimon A,LaPenta K D,et al.2006.Supercell tornadogenesis over complex terrain:The great Barrington,Massachusetts,tornado on 29 May 1995.Wea Forecasting,21(6):897-922
Brandes E A.1978.Mesocyclone evolution and tornadogenesis:Some observations.Mon Wea Rev,106(7):995-1011
Brandes E A,Vivekanandan J,Tuttle J D,et al.1995.A study of thunderstorm microphysics with multiparameter radar and aircraft observations.Mon Wea Rev,123(11):3129-3143
Browning K A,Ludlam F H,Macklin W C.1963.The density and structure of hailstones.Quart J Roy Meteor Soc,89(379):75-84
Browning K A.1964.Airflow and precipitation trajectories within severe local storms which travel to the right of the winds.J Atmos Sci,21(6):634-639
Browning K A,Wexler R.1968.The determination of kinematic properties of a wind field using Doppler radar.J Appl Meteor,7(1):105-113
Browning K A,Foote G B.1976.Airflow and hail growth in supercell storms and some implications for hail suppression.Quart JRoy Meteor Soc,102(433):499-533
Chanthavong V,Holmes J,Kernen R,et al.2010.Mitigation of sea clutter and other non-stationary echoes based on general purpose polarimetric echo identification∥6th European Conf.on Radar in Meteorology and Hydrology.Sibiu,Romania:ERAD,1-6
Dawson D T,Mansell E R,Jung Y,et al.2014.Low-level ZDRsignatures in supercell forward flanks:The role of size sorting and melting of hail.J Atmos Sci,71(1):276-299
Hall M P,Goddard J W,Cherry S M.1984.Identification of hydrometeors and other targets by dual-polarization radar.Radio Sci,19(1):132-140
H9ller H,Hagen M,Meischner P F,et al.1994.Life cycle and precipitation formation in a hybrid-type hailstorm revealed by polarimetric and Doppler radar measurements.J Atmos Sci,51(17):2500-2522
Kumjian M.2011.Precipitation properties of supercell hook echoes.Electronic J Severe Storms Meteor,6(5):1-21
Kumjian M R,Ryzhkov A.2007.Polarimetric characteristics of tornadic and nontornadic supercell thunderstorms∥33rd Conf.on Radar Meteorology.Cairns,Queensland,Australia:Amer Meteor Soc,11
Kumjian M R,Ryzhkov A V.2008.Polarimetric signatures in supercell thunderstorms.J Appl Meteor Climatol,47(7):1940-1961
Kumjian M R,Ryzhkov A V.2012.The impact of size sorting on the polarimetric radar variables.J Atmos Sci,69(6):2042-2060
Kumjian M R.2013.Principles and applications of dual-polarization weather radar.Part I:Description of the polarimetric radar variables.J Oper Meteor,1(19):226-242
Kumjian M R,Khain A P,Benmoshe N,et al.2014.The anatomy and physics of ZDR columns:Investigating apolarimetric radar signature with a spectral bin microphysical model.J Appl Meteor&Climatol,53(7):1820-1843
Lemon L R,Doswell III C A.1979.Severe thunderstorm evolution and mesocyclone structure as related to tornadogenesis.Mon Wea Rev,107(9):1184-1197
Lesins G B,List R.1986.Sponginess and drop shedding of gyrating hailstones in a pressure-controlled icing wind tunnel.J Atmos Sci,43(23):2813-2825
List R.1986.Properties and growth of hailstones∥Kessler E.Thunderstorm Dynamics and Morphology.Oklahoma:University of Oklahoma Press,259-276
Loney M L,Zrnic D S,Straka J M,et al.2002.Enhanced polarimetric radar signatures above the melting level in a supercell storm.J Appl Meteor,41(12):1179-1194
Markowski P M.2002.Hook echoes and rear-flank downdrafts:Areview.Mon Wea Rev,130(4):852-876
Marwitz J D.1972.The structure and motion of severe hailstorms.Part I:Supercell storms.J Appl Meteor,11(1):166-179
Musil D J,Heymsfield A J,Smith P L.1986.Microphysical characteristics of a well-developed weak echo region in a high plains supercell thunderstorm.J Climate Appl Meteor,25(7):1037-1051
Park H S,Ryzhkov A V,Zrnic'D S,et al.2009.The hydrometeor classification algorithm for the polarimetric WSR-88D:Description and application to an MCS.Wea Forecasting,24(3):730-748
Seliga T A,Bringi V N.1976.Potential use of radar differential reflectivity measurements at orthogonal polarizations for measuring precipitation.J Appl Meteor,15(1):69-76
Siggia A D,Passarelli J R.2004.Gaussian model adaptive processing(GMAP)for improved ground clutter cancellation and moment calculation∥Proc.3rd European Conf.on Radar in Meteorology and Hydrology.Visby,Gotland,Sweden:ERAD,67-73
Skinner P S,Weiss C C,French M M,et al.2014.VORTEX2 observations of a low-level mesocyclone with multiple internal rearflank downdraft momentum surges in the 18 May 2010 Dumas,Texas,supercell.Mon Wea Rev,142(8):2935-2960
Smith J A,Baeck M L,Zhang Y,et al.2001.Extreme Rainfall and Flooding from Supercell Thunderstorms.J Hydrometeor,2(5):469-489
Stout G E,Huff F A.1953.Radar records Illinois tornado genesis.Bull Amer Meteor Soc,34:281-284
Straka J,Zrnic'D.1993.An algorithm to deduce hydrometeor types and contents from multiparameter radar data∥Preprints,26th Conf.on Radar Meteorology.Norman,OK:Amer Meteor Soc,513-515
Weisman M L,Klemp J B.1982.The dependence of numerically simulated convective storms on vertical wind shear and buoyancy.Mon Wea Rev,110(6):504-520
Zrnic'D,Bringi V,Balakrishnan N,et al.1993.Polarimetric measurements in a severe hailstorm.Mon Wea Rev,121(8):2223-2238
曹俊武,刘黎平,葛润生.2005.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,29(5):827-836.Cao J W,Liu L P,Ge R S.2005.A study of fuzzy logic method in classification of hydrometeors based on polarimetric radar measurement.Chinese J Atmos Sci,29(5):827-836(in Chinese)
刘黎平,钱永甫,王致君.1996.用双线偏振雷达研究云内粒子相态及尺度的空间分布.气象学报,54(5):590-599.Liu L P,Qian Y F,Wang Z J.1996.The study of spacial distribution of phase and size of hydrometeorsin cloud by dual linear polarization radar.Acta Meteor Sinica,54(5):590-599(in Chinese)
苏德斌,马建立,张蔷等.2011.X波段双线偏振雷达冰雹识别初步研究.气象,37(10):1228-1232.Su D B,Ma J L,Zhang Q,et al.2011.Preliminary research on method of hail detection with X band dual linear polarization radar.Meteor Mon,37(10):1228-1232(in Chinese)
孙丝雨,沈永海,霍苗等.2013.双线偏振雷达在一次强降雹过程中的初步应用.暴雨灾害,32(3):249-255.Sun S Y,Shen YH,Huo M,et al.2013.Preliminary application of dual-polarization weather radar in a severe hail event.Torrential Rain Disaster,32(3):249-255(in Chinese)
王福侠,俞小鼎,闫雪瑾.2014.一次超级单体分裂过程的雷达回波特征分析.气象学报,72(1):152-167.Wang F X,Yu X D,Yan X J.2014.Analysis of the splitting processes of the supercell storms based on the Doppler weather radar data.Acta Meteor Sinica,72(1):152-167(in Chinese)
俞小鼎,郑媛媛,张爱民等.2006.安徽一次强烈龙卷的多普勒天气雷达分析.高原气象,25(5):914-924.Yu X D,Zheng Y Y,Zhang A M,et al.2006.The detection of a severe tornado event in Anhui with China new generation weather radar.Plateau Meteor,25(5):914-924(in Chinese)
张鸿发,郄秀书,王致君等.2001.偏振雷达观测强对流雹暴云.大气科学,25(1):38-48.Zhang H F,Qie X S,Wang Z J,et al.2001.Polarization radar observations on hailstorms.Chinese JAtmos Sci,25(1):38-48(in Chinese)
赵坤,周仲岛,潘玉洁等.2008.台湾海峡中气旋结构特征的单多普勒雷达分析.气象学报,66(4):637-651.Zhao K,Zhou Z D,Pan Y J,et al.2008.Single-Doppler radar analysis of a mesocyclone in the Taiwan Strait.Acta Meteor Sinica,66(4):637-651(in Chinese)
郑媛媛,俞小鼎,方翀等.2004.一次典型超级单体风暴的多普勒天气雷达观测分析.气象学报,62(3):317-328.Zheng Y Y,Yu X D,Fang C,et al.2004.Analysis of a strong classic supercell storm with Doppler weather radar data.Acta Meteor Sinica,62(3):317-328(in Chinese)
Anderson M E,Carey L D,Petersen W A,et al.2011.C-band dual-polarimetric radar signatures of hail.Electronic J Operat Meteor,12(2):45-75
Aydin K,Seliga T A,Balaji V.1986.Remote sensing of hail with a dual linear polarization radar.J Climate Appl Meteor,25(10):1475-1484
Balakrishnan N,Zrnic D S.1990.Use of polarization to characterize precipitation and discriminate large hail.J Atmos Sci,47(13):1525-1540
Bluestein H B,French M M,Tanamachi R L,et al.2007.Closerange observations of tornadoes in supercells made with a dualpolarization,X-band,mobile Doppler radar.Mon Wea Rev,135(4):1522-1543
Bosart L F,Seimon A,LaPenta K D,et al.2006.Supercell tornadogenesis over complex terrain:The great Barrington,Massachusetts,tornado on 29 May 1995.Wea Forecasting,21(6):897-922
Brandes E A.1978.Mesocyclone evolution and tornadogenesis:Some observations.Mon Wea Rev,106(7):995-1011
Brandes E A,Vivekanandan J,Tuttle J D,et al.1995.A study of thunderstorm microphysics with multiparameter radar and aircraft observations.Mon Wea Rev,123(11):3129-3143
Browning K A,Ludlam F H,Macklin W C.1963.The density and structure of hailstones.Quart J Roy Meteor Soc,89(379):75-84
Browning K A.1964.Airflow and precipitation trajectories within severe local storms which travel to the right of the winds.J Atmos Sci,21(6):634-639
Browning K A,Wexler R.1968.The determination of kinematic properties of a wind field using Doppler radar.J Appl Meteor,7(1):105-113
Browning K A,Foote G B.1976.Airflow and hail growth in supercell storms and some implications for hail suppression.Quart JRoy Meteor Soc,102(433):499-533
Chanthavong V,Holmes J,Kernen R,et al.2010.Mitigation of sea clutter and other non-stationary echoes based on general purpose polarimetric echo identification∥6th European Conf.on Radar in Meteorology and Hydrology.Sibiu,Romania:ERAD,1-6
Dawson D T,Mansell E R,Jung Y,et al.2014.Low-level ZDRsignatures in supercell forward flanks:The role of size sorting and melting of hail.J Atmos Sci,71(1):276-299
Hall M P,Goddard J W,Cherry S M.1984.Identification of hydrometeors and other targets by dual-polarization radar.Radio Sci,19(1):132-140
H9ller H,Hagen M,Meischner P F,et al.1994.Life cycle and precipitation formation in a hybrid-type hailstorm revealed by polarimetric and Doppler radar measurements.J Atmos Sci,51(17):2500-2522
Kumjian M.2011.Precipitation properties of supercell hook echoes.Electronic J Severe Storms Meteor,6(5):1-21
Kumjian M R,Ryzhkov A.2007.Polarimetric characteristics of tornadic and nontornadic supercell thunderstorms∥33rd Conf.on Radar Meteorology.Cairns,Queensland,Australia:Amer Meteor Soc,11
Kumjian M R,Ryzhkov A V.2008.Polarimetric signatures in supercell thunderstorms.J Appl Meteor Climatol,47(7):1940-1961
Kumjian M R,Ryzhkov A V.2012.The impact of size sorting on the polarimetric radar variables.J Atmos Sci,69(6):2042-2060
Kumjian M R.2013.Principles and applications of dual-polarization weather radar.Part I:Description of the polarimetric radar variables.J Oper Meteor,1(19):226-242
Kumjian M R,Khain A P,Benmoshe N,et al.2014.The anatomy and physics of ZDR columns:Investigating apolarimetric radar signature with a spectral bin microphysical model.J Appl Meteor&Climatol,53(7):1820-1843
Lemon L R,Doswell III C A.1979.Severe thunderstorm evolution and mesocyclone structure as related to tornadogenesis.Mon Wea Rev,107(9):1184-1197
Lesins G B,List R.1986.Sponginess and drop shedding of gyrating hailstones in a pressure-controlled icing wind tunnel.J Atmos Sci,43(23):2813-2825
List R.1986.Properties and growth of hailstones∥Kessler E.Thunderstorm Dynamics and Morphology.Oklahoma:University of Oklahoma Press,259-276
Loney M L,Zrnic D S,Straka J M,et al.2002.Enhanced polarimetric radar signatures above the melting level in a supercell storm.J Appl Meteor,41(12):1179-1194
Markowski P M.2002.Hook echoes and rear-flank downdrafts:Areview.Mon Wea Rev,130(4):852-876
Marwitz J D.1972.The structure and motion of severe hailstorms.Part I:Supercell storms.J Appl Meteor,11(1):166-179
Musil D J,Heymsfield A J,Smith P L.1986.Microphysical characteristics of a well-developed weak echo region in a high plains supercell thunderstorm.J Climate Appl Meteor,25(7):1037-1051
Park H S,Ryzhkov A V,Zrnic'D S,et al.2009.The hydrometeor classification algorithm for the polarimetric WSR-88D:Description and application to an MCS.Wea Forecasting,24(3):730-748
Seliga T A,Bringi V N.1976.Potential use of radar differential reflectivity measurements at orthogonal polarizations for measuring precipitation.J Appl Meteor,15(1):69-76
Siggia A D,Passarelli J R.2004.Gaussian model adaptive processing(GMAP)for improved ground clutter cancellation and moment calculation∥Proc.3rd European Conf.on Radar in Meteorology and Hydrology.Visby,Gotland,Sweden:ERAD,67-73
Skinner P S,Weiss C C,French M M,et al.2014.VORTEX2 observations of a low-level mesocyclone with multiple internal rearflank downdraft momentum surges in the 18 May 2010 Dumas,Texas,supercell.Mon Wea Rev,142(8):2935-2960
Smith J A,Baeck M L,Zhang Y,et al.2001.Extreme Rainfall and Flooding from Supercell Thunderstorms.J Hydrometeor,2(5):469-489
Stout G E,Huff F A.1953.Radar records Illinois tornado genesis.Bull Amer Meteor Soc,34:281-284
Straka J,Zrnic'D.1993.An algorithm to deduce hydrometeor types and contents from multiparameter radar data∥Preprints,26th Conf.on Radar Meteorology.Norman,OK:Amer Meteor Soc,513-515
Weisman M L,Klemp J B.1982.The dependence of numerically simulated convective storms on vertical wind shear and buoyancy.Mon Wea Rev,110(6):504-520
Zrnic'D,Bringi V,Balakrishnan N,et al.1993.Polarimetric measurements in a severe hailstorm.Mon Wea Rev,121(8):2223-2238