2017年5月7日广州特大暴雨微物理特征及其触发维持机制分析
|
摘要
2017年5月7日,广州经历了一次罕见的局地特大暴雨事件,刷新了多个雨量历史纪录,造成了严重的国民财产损失。本文利用双偏振雷达、二维雨滴谱仪、微波辐射计和风廓线雷达等多种新型探测资料,分析这次短时暴雨的演变过程和降水特征,并通过大气环境诊断和双多普勒雷达风场反演方法研究其维持机制。结果表明,此次降水过程发生在弱天气系统强迫条件下,大气层结表现为弱对流抑制、低抬升凝结高度、中等对流有效位能、较厚的暖云层,低层受暖湿气流影响但无明显急流。强降水是由中尺度对流系统直接产生的。午夜至凌晨的初始对流主要由偏南暖湿气流与地形相互作用产生,对流单体不断在后部触发并逐渐形成准静止的对流雨带;黎明至早晨,新生对流单体沿着成熟的强降水风暴出流与低层偏南暖湿气流的交界不断激发,后向传播过程更为显著,形成回波列车效应;此后降水以组织化的对流雨带不断南移。此次暴雨过程中的对流云团为典型的低质心降水云团,降水雨滴谱在高湿环境中表现为暖性降水的特征(小雨滴浓度非常高),但同时存在部分大粒子,从而导致更高的降水效率和局地强降水。不断加强的低层偏南暖湿气流对于对流系统的发展和维持具有重要作用。
An extremely heavy rainfall event occurred in Guangzhou City on 7 May 2017.The record-breaking heavy precipitation caused severe property damage.To investigate the reasons/mechanisms responsible for the severe rainfall,a detailed observation analysis was performed in this study,based on the dataset collected by ground-based Doppler radars,two-dimensional video disdrometer(2 DVD),microwave radiometer and wind-profiling radar.The research results show that the ambient conditions prior to this event are characterized by small value of convective inhibition(CIN),low lifting condensation level(LCL),moderate convective available potential energy(CAPE),deep warm layer,and moist southerly flow.From midnight to dawn of 7 May 2017,initial convection was generated mainly by the terrain-blocked southerly flow,leading to the formation of quasi-stationary rainbands.From sunrise to early morning,new convective cells were repeatedly triggered along the precipitation-induced outflows boundary(i.e.,back building process)and were continuously propagated backward(i.e.,"echo training").The observaiton of 2 DVD further suggests that the surface heavy precipitation was composed of a high concentration of small raindrops and a few large raindrops.This microphysical information indicates that the high-precipitation-efficiency warm rain process was the main microphysical mechnism responsible for the heavy rainfall.This argument is supported with the low-centroid cumulonimbus structures observed by Doppler radar.It suggests that the continuously intensifying southerly flow played an important role in sustaining the convective system and producing the local heavy rainfall.
An extremely heavy rainfall event occurred in Guangzhou City on 7 May 2017.The record-breaking heavy precipitation caused severe property damage.To investigate the reasons/mechanisms responsible for the severe rainfall,a detailed observation analysis was performed in this study,based on the dataset collected by ground-based Doppler radars,two-dimensional video disdrometer(2 DVD),microwave radiometer and wind-profiling radar.The research results show that the ambient conditions prior to this event are characterized by small value of convective inhibition(CIN),low lifting condensation level(LCL),moderate convective available potential energy(CAPE),deep warm layer,and moist southerly flow.From midnight to dawn of 7 May 2017,initial convection was generated mainly by the terrain-blocked southerly flow,leading to the formation of quasi-stationary rainbands.From sunrise to early morning,new convective cells were repeatedly triggered along the precipitation-induced outflows boundary(i.e.,back building process)and were continuously propagated backward(i.e.,"echo training").The observaiton of 2 DVD further suggests that the surface heavy precipitation was composed of a high concentration of small raindrops and a few large raindrops.This microphysical information indicates that the high-precipitation-efficiency warm rain process was the main microphysical mechnism responsible for the heavy rainfall.This argument is supported with the low-centroid cumulonimbus structures observed by Doppler radar.It suggests that the continuously intensifying southerly flow played an important role in sustaining the convective system and producing the local heavy rainfall.
引文
陈思,高建芸,黄丽娜,等,2017.华南前汛期持续性暴雨年代际变化特征及成因[J].应用气象学报,28(1):86-97.
韩珏靖,陈飞,张臻,等,2015.MP-3000A型地基微波辐射计的资料质量评估和探测特征分析[J].气象,41(2):226-233.
何立富,陈涛,孔期,2016.华南暖区暴雨研究进展[J].应用气象学报,27(5):559-569.
孔期,林建,2017.2015年5月19-20日华南地区不同性质暴雨成因和预报分析[J].气象,43(7):792-803.
林良勋,冯业荣,黄忠,等,2006.广东省天气预报技术手册[M].北京:气象出版社:119.
潘玉洁,赵坤,潘益农,等,2012.用双多普勒雷达分析华南一次飑线系统的中尺度结构特征[J].气象学报,70(4):736-751.
孙继松,雷蕾,于波,等,2015.近10年北京地区极端暴雨事件的基本特征[J].气象学报,73(4):609-623.
田付友,郑永光,张小玲,等,2018.2017年5月7日广州极端强降水对流系统结构、触发和维持机制[J].气象,44(4):469-484.
温龙,刘溯,赵坤,等,2015.两次降水过程的微降雨雷达探测精度分析[J].气象,41(5):577-587.
伍志方,蔡景就,林良勋,等,2018.广州2017“5.7”暖区特大暴雨的中尺度系统和可预报性[J].气象,44(4):485-499.
薛纪善,1999.1994年华南夏季特大暴雨研究[M].北京:气象出版社:185.
郑永光,陶祖钰,俞小鼎,2017.强对流天气预报的一些基本问题[J].气象,43(6):641-652.
周秀骥,薛纪善,陶祖钰,等,2003.'98华南暴雨科学试验研究[M].北京:气象出版社:370.
Chappell C F,1986.Quasi-stationary convective events[M]∥Ray PS.Mesoscale Meteorology and Forecasting.Boston,MA:Springer:289-310.
Corfidi S F,2003.Cold pools and MCS propagation:forecasting the motion of downwind-developing MCSs[J].Wea Forecasting,18(6):997-1017.
Cressman G P,1959.An operational objective analysis system[J].Mon Wea Rev,87(10):367-374.
Davis R S,2001.Flash flood forecast and detection methods[M]∥Doswell III C A.Severe Convective Storms.Boston,Springer:481-525.
Doswell III C A,2001.Severe convective storms-an overview[M]∥Doswell III C A.Severe Convective Storms.Boston,Springer:1-26.
Doswell III C A,Brooks H E,Maddox R A,1996.Flash flood forecasting:an ingredients-based methodology[J].Wea Forecasting,11(4):560-581.
Houze Jr R A,2014.Cloud dynamics[M].2nd ed.New York:Academic Press:187-236.
Kuo Y H,Chen G T J,1990.The Taiwan area mesoscale experiment(TAMEX):an overview[J].Bull Amer Meteor Soc,71(4):488-503.
Li Jun,Chen Yileng,Lee W C,1997.Analysis of a heavy rainfall event during TAMEX[J].Mon Wea Rev,125(6):1060-1082.
Maddox R A,Chappell C F,Hoxit L R,1979.Synoptic and meso-αscale aspects of flash flood events[J].Bull Amer Meteor Soc,60(2):115-123.
Oye R,Mueller C,Smith S,1995.Software for radar translation,visualization,editing,and interpolation[C]∥Proceedings of the27th Conference on Radar Meteorology.Vail,American Meteorological Society:359-361.
Parker M D,Johnson R H,2000.Organizational modes of midlatitude mesoscale convective systems[J].Mon Wea Rev,128(10):3413-3436.
Pontrelli M D,Bryan G,Fritsch J M,1999.The Madison County,Virginia,flash flood of 27June 1995[J].Wea Forecasting,14(3):384-404.
Ray P S,Wagner K K,Johnson K W,et al,1978.Triple-Doppler observations of a convective storm[J].J Appl Meteo,17(8):1201-1212.
Sanders F,2000.Frontal focusing of a flooding rainstorm[J].Mon Wea Rev,128(12):4155-4159.
Schumacher R S,Johnson R H,2005.Organization and environmental properties of extreme-rain-producing mesoscale convective systems[J].Mon Wea Rev,133(4):961-976.
Schumacher R S,Johnson R H,2006.Characteristics of U.S.extreme rain events during 1999-2003[J].Wea Forecasting,21(1):69-85.
Schumacher R S,Johnson R H,2008.Mesoscale processes contributing to extreme rainfall in a midlatitude warm-season flash flood[J].Mon Wea Rev,136(10):3964-3986.
Schumacher R S,Johnson R H,2009.Quasi-stationary,extreme-rainproducing convective systems associated with midlevel cyclonic circulations[J].Wea Forecasting,24(2):555-574.
Soderholm B,Ronalds B,Kirshbaum D J,2014.The evolution of convective storms initiated by an isolated mountain ridge[J].Mon Wea Rev,142(4):1430-1451.
Wang Hui,Luo Yali,Jou B J D,2014.Initiation,maintenance,and properties of convection in an extreme rainfall event during SC-MREX:observational analysis[J].J Geophys Res,119(23):13206-13232.
Weisman M L,Klemp J B,Rotunno R,1988.Structure and evolution of numerically simulated squall lines[J].J Atmos Sci,45(14):1990-2013.
Wen Long,Zhao Kun,Zhang Guifu,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].J Geophys Res,121(5):2265-2282.
Xu Weixin,Zipser E J,2011.Diurnal variations of precipitation,deep convection,and lightning over and east of the eastern Tibetan Plateau[J].J Climate,24(2):448-465.
Xu Weixin,Zipser E J,2012.Properties of deep convection in tropical continental,monsoon,and oceanic rainfall regimes[J].Geophys Res Lett,39(7):L07802.
Xu Weixin,Zipser E J,Liu Chuntao,2009.Rainfall characteristics and convective properties of mei-yu precipitation systems over South China,Taiwan,and the South China Sea.Part I:TRMMobservations[J].Mon Wea Rev,137(12):4261-4275.
Xu Weixin,Zipser E J,Chen Yileng,et al,2012.An orography-associated extreme rainfall event during TiMREX:initiation,storm evolution,and maintenance[J].Mon Wea Rev,140(8):2555-2574.
Zhang Qinghong,Lau K H,Kuo Y H,et al,2003.A numerical study of a mesoscale convective system over the Taiwan Strait[J].Mon Wea Rev,131(6):1150-1170.
韩珏靖,陈飞,张臻,等,2015.MP-3000A型地基微波辐射计的资料质量评估和探测特征分析[J].气象,41(2):226-233.
何立富,陈涛,孔期,2016.华南暖区暴雨研究进展[J].应用气象学报,27(5):559-569.
孔期,林建,2017.2015年5月19-20日华南地区不同性质暴雨成因和预报分析[J].气象,43(7):792-803.
林良勋,冯业荣,黄忠,等,2006.广东省天气预报技术手册[M].北京:气象出版社:119.
潘玉洁,赵坤,潘益农,等,2012.用双多普勒雷达分析华南一次飑线系统的中尺度结构特征[J].气象学报,70(4):736-751.
孙继松,雷蕾,于波,等,2015.近10年北京地区极端暴雨事件的基本特征[J].气象学报,73(4):609-623.
田付友,郑永光,张小玲,等,2018.2017年5月7日广州极端强降水对流系统结构、触发和维持机制[J].气象,44(4):469-484.
温龙,刘溯,赵坤,等,2015.两次降水过程的微降雨雷达探测精度分析[J].气象,41(5):577-587.
伍志方,蔡景就,林良勋,等,2018.广州2017“5.7”暖区特大暴雨的中尺度系统和可预报性[J].气象,44(4):485-499.
薛纪善,1999.1994年华南夏季特大暴雨研究[M].北京:气象出版社:185.
郑永光,陶祖钰,俞小鼎,2017.强对流天气预报的一些基本问题[J].气象,43(6):641-652.
周秀骥,薛纪善,陶祖钰,等,2003.'98华南暴雨科学试验研究[M].北京:气象出版社:370.
Chappell C F,1986.Quasi-stationary convective events[M]∥Ray PS.Mesoscale Meteorology and Forecasting.Boston,MA:Springer:289-310.
Corfidi S F,2003.Cold pools and MCS propagation:forecasting the motion of downwind-developing MCSs[J].Wea Forecasting,18(6):997-1017.
Cressman G P,1959.An operational objective analysis system[J].Mon Wea Rev,87(10):367-374.
Davis R S,2001.Flash flood forecast and detection methods[M]∥Doswell III C A.Severe Convective Storms.Boston,Springer:481-525.
Doswell III C A,2001.Severe convective storms-an overview[M]∥Doswell III C A.Severe Convective Storms.Boston,Springer:1-26.
Doswell III C A,Brooks H E,Maddox R A,1996.Flash flood forecasting:an ingredients-based methodology[J].Wea Forecasting,11(4):560-581.
Houze Jr R A,2014.Cloud dynamics[M].2nd ed.New York:Academic Press:187-236.
Kuo Y H,Chen G T J,1990.The Taiwan area mesoscale experiment(TAMEX):an overview[J].Bull Amer Meteor Soc,71(4):488-503.
Li Jun,Chen Yileng,Lee W C,1997.Analysis of a heavy rainfall event during TAMEX[J].Mon Wea Rev,125(6):1060-1082.
Maddox R A,Chappell C F,Hoxit L R,1979.Synoptic and meso-αscale aspects of flash flood events[J].Bull Amer Meteor Soc,60(2):115-123.
Oye R,Mueller C,Smith S,1995.Software for radar translation,visualization,editing,and interpolation[C]∥Proceedings of the27th Conference on Radar Meteorology.Vail,American Meteorological Society:359-361.
Parker M D,Johnson R H,2000.Organizational modes of midlatitude mesoscale convective systems[J].Mon Wea Rev,128(10):3413-3436.
Pontrelli M D,Bryan G,Fritsch J M,1999.The Madison County,Virginia,flash flood of 27June 1995[J].Wea Forecasting,14(3):384-404.
Ray P S,Wagner K K,Johnson K W,et al,1978.Triple-Doppler observations of a convective storm[J].J Appl Meteo,17(8):1201-1212.
Sanders F,2000.Frontal focusing of a flooding rainstorm[J].Mon Wea Rev,128(12):4155-4159.
Schumacher R S,Johnson R H,2005.Organization and environmental properties of extreme-rain-producing mesoscale convective systems[J].Mon Wea Rev,133(4):961-976.
Schumacher R S,Johnson R H,2006.Characteristics of U.S.extreme rain events during 1999-2003[J].Wea Forecasting,21(1):69-85.
Schumacher R S,Johnson R H,2008.Mesoscale processes contributing to extreme rainfall in a midlatitude warm-season flash flood[J].Mon Wea Rev,136(10):3964-3986.
Schumacher R S,Johnson R H,2009.Quasi-stationary,extreme-rainproducing convective systems associated with midlevel cyclonic circulations[J].Wea Forecasting,24(2):555-574.
Soderholm B,Ronalds B,Kirshbaum D J,2014.The evolution of convective storms initiated by an isolated mountain ridge[J].Mon Wea Rev,142(4):1430-1451.
Wang Hui,Luo Yali,Jou B J D,2014.Initiation,maintenance,and properties of convection in an extreme rainfall event during SC-MREX:observational analysis[J].J Geophys Res,119(23):13206-13232.
Weisman M L,Klemp J B,Rotunno R,1988.Structure and evolution of numerically simulated squall lines[J].J Atmos Sci,45(14):1990-2013.
Wen Long,Zhao Kun,Zhang Guifu,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].J Geophys Res,121(5):2265-2282.
Xu Weixin,Zipser E J,2011.Diurnal variations of precipitation,deep convection,and lightning over and east of the eastern Tibetan Plateau[J].J Climate,24(2):448-465.
Xu Weixin,Zipser E J,2012.Properties of deep convection in tropical continental,monsoon,and oceanic rainfall regimes[J].Geophys Res Lett,39(7):L07802.
Xu Weixin,Zipser E J,Liu Chuntao,2009.Rainfall characteristics and convective properties of mei-yu precipitation systems over South China,Taiwan,and the South China Sea.Part I:TRMMobservations[J].Mon Wea Rev,137(12):4261-4275.
Xu Weixin,Zipser E J,Chen Yileng,et al,2012.An orography-associated extreme rainfall event during TiMREX:initiation,storm evolution,and maintenance[J].Mon Wea Rev,140(8):2555-2574.
Zhang Qinghong,Lau K H,Kuo Y H,et al,2003.A numerical study of a mesoscale convective system over the Taiwan Strait[J].Mon Wea Rev,131(6):1150-1170.