青藏高原对流云的偏振雷达观测研究
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摘要
利用可移动式C波段双偏振雷达(C-POL),以及那曲新一代天气雷达(CINRAD/CD)于2014年7月30日和8月5日在西藏那曲地区的观测资料,并通过双多普勒雷达风场反演、偏振雷达相态识别,清晰展示了这两次高原冰雹云发生发展的动力、微物理、热力结构特征。结果表明:青藏高原地区的对流云多在午后出现,水平及垂直尺度不大,但是对流云发生频繁、生消快,一般持续几十分钟。从RHI扫描的水平偏振反射率因子(ZH)、差分反射率因子(ZDR),以及反演的相态(Class)分布上可以明显看出,粒子跟随"0线"抬高,不断增长,回波强度也越来越大,并最终超过主上升气流从另一侧降落,形成冰雹墙的整个动力与微物理过程。从连续时次的RHI上还观测到一次对流单体发生、发展过程中相态从湿雪到冰雹的变化,单体刚刚触发时,回波高度不高,强度还很弱,但是却出现成片的湿雪区域,说明上升气流非常旺盛,将本来落到0℃层以下的未完全融化的湿雪重新带到0℃层以上,通过凝华、凇附、攀附等物理过程,仅仅10多分钟,这些湿雪就能够迅速增长成为冰雹。这些湿雪重新凝结过程中,释放潜热,进一步促进了不稳定结构,加强了上升气流和下沉气流。因此,如果某个刚刚生成的弱回波区域内,在融化层以上出现大量的湿雪,往往预示着该区域上升气流强劲,会迅速发展成强回波单体。
Based on observations of a mobile C-band dual polarimetric radar(C-POL) and the Chinese new generation weather radar deployed in Naqu(CINRAD/CD) from 30 July to 5 August 2014, two hailstorm events and their associated dynamic, thermal-dynamic and microphysical characteristics are demonstrated using wind fields retrieved from observations of the two Doppler radars and identification technique of dual polarization radar hydrometeors. The convective cells mostly appeared in the afternoon in the Tibetan Plateau. Although the horizontal and vertical scales of the convective cells are small, they occurred frequently and evolved rapidly, and generally lasted for tens of minutes. In the RHI(range height indicator) images of Z_H, Z_(DR) and Class, the dynamic and microphysical processes can be seen clearly. Hydrometeor particles reached higher levels following the "0 line" and grew quickly, accompanied by increases in the echo intensity, and eventually formed a hail wall dropping down on the other side of main updraft. From the consecutive three RHI scans, it can be seen that the particles changed from wet snow to hailstorm during the evolutional process in one convective cell. The height of the echo was lower and its intensity was very weak when the convective cell was initially triggered. However, large amounts of wet snow appeared above the melting level, indicating that the updraft was strong enough to transport wet snow back to higher levels before the snow completely melted below the melting level. Through physical processes such as condensation, rime and attachment, the wet snow could rapidly grow into hailstones in just over 10 min. During the re-condensation of wet snow, the unstable structure further developed while the ascending and descending motions strengthened due to the latent heat release. Therefore, the occurrence of wet snow in a newly generated weak echo region above the melting level usually indicates strong updraft and convective cell would develop rapidly.
Based on observations of a mobile C-band dual polarimetric radar(C-POL) and the Chinese new generation weather radar deployed in Naqu(CINRAD/CD) from 30 July to 5 August 2014, two hailstorm events and their associated dynamic, thermal-dynamic and microphysical characteristics are demonstrated using wind fields retrieved from observations of the two Doppler radars and identification technique of dual polarization radar hydrometeors. The convective cells mostly appeared in the afternoon in the Tibetan Plateau. Although the horizontal and vertical scales of the convective cells are small, they occurred frequently and evolved rapidly, and generally lasted for tens of minutes. In the RHI(range height indicator) images of Z_H, Z_(DR) and Class, the dynamic and microphysical processes can be seen clearly. Hydrometeor particles reached higher levels following the "0 line" and grew quickly, accompanied by increases in the echo intensity, and eventually formed a hail wall dropping down on the other side of main updraft. From the consecutive three RHI scans, it can be seen that the particles changed from wet snow to hailstorm during the evolutional process in one convective cell. The height of the echo was lower and its intensity was very weak when the convective cell was initially triggered. However, large amounts of wet snow appeared above the melting level, indicating that the updraft was strong enough to transport wet snow back to higher levels before the snow completely melted below the melting level. Through physical processes such as condensation, rime and attachment, the wet snow could rapidly grow into hailstones in just over 10 min. During the re-condensation of wet snow, the unstable structure further developed while the ascending and descending motions strengthened due to the latent heat release. Therefore, the occurrence of wet snow in a newly generated weak echo region above the melting level usually indicates strong updraft and convective cell would develop rapidly.
引文
蔡淼, 周毓荃, 蒋元华等. 2014. 一次超级单体雹暴观测分析和成雹区识别研究. 大气科学, 38(5): 845-860. Cai M, Zhou Y Q, Jiang Y H, et al. 2014. Observations, analysis, and hail-forming area identification of a supercell hailstorm. Chinese J Atmos Sci, 38(5): 845-860 (in Chinese)
常祎, 郭学良. 2016. 青藏高原那曲地区夏季对流云结构及雨滴谱分布日变化特征. 科学通报, 61(15): 1706-1720. Chang Y, Guo X L. 2016. Characteristics of convective cloud and precipitation during summer time at Naqu over Tibetan Plateau. Chinese Sci Bull, 61(15): 1706-1720 (in Chinese)
陈秋萍, 冯晋勤, 陈冰等. 2003. 新一代天气雷达观测的福建夏季对流云特征. 应用气象学报, 14(S1): 180-186. Chen Q P, Feng J Q, Chen B, et al. 2003. CINRAD observation on convective clouds in summer in south China. J Appl Meteor Sci, 14(S1): 180-186 (in Chinese)
戴进, 余兴, 刘贵华等. 2010. 一次暴雨过程中云微物理特征的卫星反演分析. 气象学报, 68(3): 387-397. Dai J, Yu X, Liu G H, et al. 2010. Analyses of satellite retrieval microphysical properties of a rainstorm in the northern part of Shaanxi. Acta Meteor Sinica, 68(3): 387-397 (in Chinese)
杜牧云, 刘黎平, 胡志群等. 2011. C波段双线偏振多普勒雷达资料质量分析. 暴雨灾害, 30(4): 328-334. Du M Y, Liu L P, Hu Z Q, et al. 2011. Data quality analysis of C-band dual linear polarimetric radar. Torr Rain Dis, 30(4): 328-334 (in Chinese)
杜牧云, 刘黎平, 胡志群等. 2013. 双线偏振多普勒雷达资料质量分析. 气象学报, 71(1): 146-158. Du M Y, Liu L P, Hu Z Q, et al. 2013. An analysis of dual-linear polarimetric Doppler radar data quality. Acta Meteor Sinica, 71(1): 146-158 (in Chinese)
傅云飞. 2014. 利用卫星双光谱反射率算法反演的云参数及其应用. 气象学报, 72(5): 1039-1053. Fu Y F. 2014. Cloud parameters retrieved by the bispectral reflectance algorithm and associated applications. Acta Meteor Sinica, 72(5): 1039-1053 (in Chinese)
胡志群, 刘黎平, 吴林林. 2014. C波段偏振雷达几种系统误差标定方法对比分析. 高原气象, 33(1): 221-231. Hu Z Q, Liu L P, Wu L L. 2014. Comparison among several system biases calibration methods on C-band polarimetric radar. Plateau Meteor, 33(1): 221-231 (in Chinese)
江吉喜, 范梅珠. 2002. 夏季青藏高原上的对流云和中尺度对流系统. 大气科学, 26(2): 263-270. Jiang J X, Fan M Z. 2002. Convective clouds and mesoscale convective systems over the Tibetan plateau in summer. Chinese J Atmos Sci, 26(2): 263-270 (in Chinese)
李典, 白爱娟, 黄盛军. 2012. 利用TRMM卫星资料对青藏高原地区强对流天气特征分析. 高原气象, 31(2): 304-311. Li D, Bai A J, Huang S J. 2012. Characteristic analysis of a severe convective weather over Tibetan Plateau based on TRMM data. Plateau Meteor, 31(2): 304-311 (in Chinese)
刘俊卿. 2007. 西藏高原冰雹形成机理及人工催化的数值研究[D]. 南京: 南京信息工程大学. Liu J Q. 2007. The numberical study on the formation mechanism and suppression of hailstorms in Tibet Plateau[D]. Nanjing: Nanjing University of Information Science & Technology (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 hydrometeors in cloud by dual linear polarization radar. Acta Meteor Sinica, 54(5): 590-599 (in Chinese)
刘黎平, 郑佳锋, 阮征等. 2015. 2014年青藏高原云和降水多种雷达综合观测试验及云特征初步分析结果. 气象学报, 73(4): 635-647. Liu L P, Zheng J F, Ruan Z, et al. 2015. The preliminary analyses of the cloud properties over the Tibetan Plateau from the field experiments in clouds precipitation with the vavious radars. Acta Meteor Sinica, 73(4): 635-647 (in Chinese)
马宗晋. 1994. 中国重大自然灾害及减灾对策(总论). 北京: 科学出版社. Ma Z J. 1994. Major Natural Disasters and Countermeasures for Disaster Reduction in China (General Introduction). Beijing: Science Press (in Chinese)
王文新, 郑国光, 瓦黑提. 1986. 玛纳斯冰雹微物理个例分析. 新疆气象, (9): 31-32. Wang W X, Zheng G G, Wa H T. 1986. A case study of hail microphysics in Manasi. Bimonthly Xinjiang Meteor, (9): 33-34 (in Chinese)
吴汪毅. 2006. 安徽夏季对流云的多普勒雷达特征//中国气象学会2006年年会“人工影响天气作业技术专题研讨会”分会场论文集. 成都: 中国气象学会. Wu W Y. 2006. Doppler radar characteristics of summer convective cloud in Anhui Province//Proceedings of Annual Meeting of the Chinese Meteorological Society on 2006. Chengdu: China Meteorological Society (in Chinese)
许焕斌, 段英. 2001. 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. 大气科学, 25(2): 277-288. Xu H B, Duan Y. 2001. The mechanism of hailstone's formation and the hail-suppression hypothesis: "Beneficial competition". Chinese J Atmos Sci, 25(2): 277-288 (in Chinese)
许焕斌, 田利庆. 2008. 强对流云中“穴道”的物理含义和应用. 应用气象学报, 19(3): 372-379. Xu H B, Tian L Q. 2008. Physical meanings of "cave channel" in strong convective storm with its application. J Appl Meteor Sci, 19(3): 372-379 (in Chinese)
赵鸣, 苗曼倩. 1992. 大气边界层. 北京: 气象出版社. Zhao M, Miao M Q. 1992. Atmospheric Boundary Layer. Beijing: China Meteorological Press (in Chinese)
周德平, 杨洋, 王吉宏等. 2007. 冰雹云雷达识别方法及防雹作业经验. 气象科技, 35(2): 258-263. Zhou D P, Yang Y, Wang J H, et al. 2007. Hail cloud identification method by radar echoes and experiences from hail suppression operation in Liaoning Province. Meteor Sci Technol, 35(2): 258-263 (in Chinese)
Direskeneli H, Aydin K, SelignT A. 1986. Radar estimation of rainfall rate using reflectivity factor and differential reflectivity measurements obtained during MAYPOLE84: Comparison with ground-based raingages//Proceedings of the 23rd Conference on Radar Meteor, Snowmass. Colorado: Amer Meteor Soc, 116-120
Park H S, Ryzhkov A V, Zrni【math63z】, et al. 2009. The hydrometeor classification algorithm for the polarimetric WSR-88D: Description and application to an MCS. Wea Forecasting, 24(3): 730-748
Sachidananda M, Zrnic D S.1986.A comparison of rainrate estimates from differential propagation phase shift, differential reflectivity and Z-R relationships//Proceedings of the 23rd Conference on Radar Met Snowmass. Colorado: Amer Meteor Soc, 129-132
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
Seliga T A, Bringi V N, Al-khatib H H. 1981. A preliminary study of comparative measurements of rainfall rate using the differential reflectivity radar technique and a raingage network. J Appl Meteor, 20(11): 1362-1368
Uyeda H, Yamada H, Horikomi J, et al. 2001. Characteristics of convective clouds observed by a Doppler radar at Naqu on Tibetan Plateau during the GAME-Tibet IOP. J Meteor Soc Japan, 79(1): 463-474
Yanai M, Li C, Song Z. 1992. Seasonal heating of the Tibetan Plateau and its effects on the evolution of the Asian summer monsoon. J Meteor Soc Japan, 70(1): 189-221
Yanai M, Li C F. 1994. Mechanism of heating and the boundary layer over the Tibetan Plateau. Mon Wea Rev, 122(2): 305-323
常祎, 郭学良. 2016. 青藏高原那曲地区夏季对流云结构及雨滴谱分布日变化特征. 科学通报, 61(15): 1706-1720. Chang Y, Guo X L. 2016. Characteristics of convective cloud and precipitation during summer time at Naqu over Tibetan Plateau. Chinese Sci Bull, 61(15): 1706-1720 (in Chinese)
陈秋萍, 冯晋勤, 陈冰等. 2003. 新一代天气雷达观测的福建夏季对流云特征. 应用气象学报, 14(S1): 180-186. Chen Q P, Feng J Q, Chen B, et al. 2003. CINRAD observation on convective clouds in summer in south China. J Appl Meteor Sci, 14(S1): 180-186 (in Chinese)
戴进, 余兴, 刘贵华等. 2010. 一次暴雨过程中云微物理特征的卫星反演分析. 气象学报, 68(3): 387-397. Dai J, Yu X, Liu G H, et al. 2010. Analyses of satellite retrieval microphysical properties of a rainstorm in the northern part of Shaanxi. Acta Meteor Sinica, 68(3): 387-397 (in Chinese)
杜牧云, 刘黎平, 胡志群等. 2011. C波段双线偏振多普勒雷达资料质量分析. 暴雨灾害, 30(4): 328-334. Du M Y, Liu L P, Hu Z Q, et al. 2011. Data quality analysis of C-band dual linear polarimetric radar. Torr Rain Dis, 30(4): 328-334 (in Chinese)
杜牧云, 刘黎平, 胡志群等. 2013. 双线偏振多普勒雷达资料质量分析. 气象学报, 71(1): 146-158. Du M Y, Liu L P, Hu Z Q, et al. 2013. An analysis of dual-linear polarimetric Doppler radar data quality. Acta Meteor Sinica, 71(1): 146-158 (in Chinese)
傅云飞. 2014. 利用卫星双光谱反射率算法反演的云参数及其应用. 气象学报, 72(5): 1039-1053. Fu Y F. 2014. Cloud parameters retrieved by the bispectral reflectance algorithm and associated applications. Acta Meteor Sinica, 72(5): 1039-1053 (in Chinese)
胡志群, 刘黎平, 吴林林. 2014. C波段偏振雷达几种系统误差标定方法对比分析. 高原气象, 33(1): 221-231. Hu Z Q, Liu L P, Wu L L. 2014. Comparison among several system biases calibration methods on C-band polarimetric radar. Plateau Meteor, 33(1): 221-231 (in Chinese)
江吉喜, 范梅珠. 2002. 夏季青藏高原上的对流云和中尺度对流系统. 大气科学, 26(2): 263-270. Jiang J X, Fan M Z. 2002. Convective clouds and mesoscale convective systems over the Tibetan plateau in summer. Chinese J Atmos Sci, 26(2): 263-270 (in Chinese)
李典, 白爱娟, 黄盛军. 2012. 利用TRMM卫星资料对青藏高原地区强对流天气特征分析. 高原气象, 31(2): 304-311. Li D, Bai A J, Huang S J. 2012. Characteristic analysis of a severe convective weather over Tibetan Plateau based on TRMM data. Plateau Meteor, 31(2): 304-311 (in Chinese)
刘俊卿. 2007. 西藏高原冰雹形成机理及人工催化的数值研究[D]. 南京: 南京信息工程大学. Liu J Q. 2007. The numberical study on the formation mechanism and suppression of hailstorms in Tibet Plateau[D]. Nanjing: Nanjing University of Information Science & Technology (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 hydrometeors in cloud by dual linear polarization radar. Acta Meteor Sinica, 54(5): 590-599 (in Chinese)
刘黎平, 郑佳锋, 阮征等. 2015. 2014年青藏高原云和降水多种雷达综合观测试验及云特征初步分析结果. 气象学报, 73(4): 635-647. Liu L P, Zheng J F, Ruan Z, et al. 2015. The preliminary analyses of the cloud properties over the Tibetan Plateau from the field experiments in clouds precipitation with the vavious radars. Acta Meteor Sinica, 73(4): 635-647 (in Chinese)
马宗晋. 1994. 中国重大自然灾害及减灾对策(总论). 北京: 科学出版社. Ma Z J. 1994. Major Natural Disasters and Countermeasures for Disaster Reduction in China (General Introduction). Beijing: Science Press (in Chinese)
王文新, 郑国光, 瓦黑提. 1986. 玛纳斯冰雹微物理个例分析. 新疆气象, (9): 31-32. Wang W X, Zheng G G, Wa H T. 1986. A case study of hail microphysics in Manasi. Bimonthly Xinjiang Meteor, (9): 33-34 (in Chinese)
吴汪毅. 2006. 安徽夏季对流云的多普勒雷达特征//中国气象学会2006年年会“人工影响天气作业技术专题研讨会”分会场论文集. 成都: 中国气象学会. Wu W Y. 2006. Doppler radar characteristics of summer convective cloud in Anhui Province//Proceedings of Annual Meeting of the Chinese Meteorological Society on 2006. Chengdu: China Meteorological Society (in Chinese)
许焕斌, 段英. 2001. 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. 大气科学, 25(2): 277-288. Xu H B, Duan Y. 2001. The mechanism of hailstone's formation and the hail-suppression hypothesis: "Beneficial competition". Chinese J Atmos Sci, 25(2): 277-288 (in Chinese)
许焕斌, 田利庆. 2008. 强对流云中“穴道”的物理含义和应用. 应用气象学报, 19(3): 372-379. Xu H B, Tian L Q. 2008. Physical meanings of "cave channel" in strong convective storm with its application. J Appl Meteor Sci, 19(3): 372-379 (in Chinese)
赵鸣, 苗曼倩. 1992. 大气边界层. 北京: 气象出版社. Zhao M, Miao M Q. 1992. Atmospheric Boundary Layer. Beijing: China Meteorological Press (in Chinese)
周德平, 杨洋, 王吉宏等. 2007. 冰雹云雷达识别方法及防雹作业经验. 气象科技, 35(2): 258-263. Zhou D P, Yang Y, Wang J H, et al. 2007. Hail cloud identification method by radar echoes and experiences from hail suppression operation in Liaoning Province. Meteor Sci Technol, 35(2): 258-263 (in Chinese)
Direskeneli H, Aydin K, SelignT A. 1986. Radar estimation of rainfall rate using reflectivity factor and differential reflectivity measurements obtained during MAYPOLE84: Comparison with ground-based raingages//Proceedings of the 23rd Conference on Radar Meteor, Snowmass. Colorado: Amer Meteor Soc, 116-120
Park H S, Ryzhkov A V, Zrni【math63z】, et al. 2009. The hydrometeor classification algorithm for the polarimetric WSR-88D: Description and application to an MCS. Wea Forecasting, 24(3): 730-748
Sachidananda M, Zrnic D S.1986.A comparison of rainrate estimates from differential propagation phase shift, differential reflectivity and Z-R relationships//Proceedings of the 23rd Conference on Radar Met Snowmass. Colorado: Amer Meteor Soc, 129-132
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
Seliga T A, Bringi V N, Al-khatib H H. 1981. A preliminary study of comparative measurements of rainfall rate using the differential reflectivity radar technique and a raingage network. J Appl Meteor, 20(11): 1362-1368
Uyeda H, Yamada H, Horikomi J, et al. 2001. Characteristics of convective clouds observed by a Doppler radar at Naqu on Tibetan Plateau during the GAME-Tibet IOP. J Meteor Soc Japan, 79(1): 463-474
Yanai M, Li C, Song Z. 1992. Seasonal heating of the Tibetan Plateau and its effects on the evolution of the Asian summer monsoon. J Meteor Soc Japan, 70(1): 189-221
Yanai M, Li C F. 1994. Mechanism of heating and the boundary layer over the Tibetan Plateau. Mon Wea Rev, 122(2): 305-323