飑线中尺度三维精细结构的双多普勒雷达研究

This project investigates the fine structure of the squall line with the dual-Doppler radar retrieval three-dimensional wind field. The optimal dual-Doppler radar networks synchronous observation data would been employed to retrieve the 3D wind. Some squall line storms synchronous observation data detected by the dual-Doppler radar networks from 2007 to 2010,include Bejing dual-Doppler, Nanjing-Maanshan dual-Doppler, and Guangzhou-Shenzhen dual-Doppler,have been collected. We will also collect the squall line data detected by the dual-Doppler, inlcude Nanjing-Maanshan, Guangzhou-Shenzhen,Ningbo-Zhoushan,and Shanghai dual-Doppler from 2010 to 2016..Firstly, we will make use of the dual-Doppler radar 3D wind retrieval technique to retrieve the 3D wind field of the squall line system. Then, the automatic weather station observation data, the sounding data,the meteorological satellite observation data, the NCEP reanalysis data, and the dual-Doppler radar retrieval 3D wind fields are employed synthetically to study the fine 3D structure of the squall line system. The structure evolvement characteristic of the squall line in its whole life will be studied. The 3D structure of the convective systems, such as the hailstone and the heavy precipitation, in the squall line would be researched too. The relationship between the wind structure characteristic and the squall line development based on the retrieval 3D wind is also indicated.The refined rear-to-front flow and the front-to-rear flow structure in the convective region and the stratiform region of the squall line in the mature stage is investigated by the dual-Doppler retrieval wind..The contrastive analyse is applied to the difference between the squall lines in North China and the ones in South China. Furthermore, the refined conceptual models of the squall line in the mature stage is presented through this study. This project is not only very important for investigating the maintenance mechanism and the refined structure of the squall line, but also for imporving the squall line nowcasting.

利用已经收集到的最佳双多普勒天气雷达观测网探测到的多个飑线天气的双雷达时间同步体扫数据(北京双雷达、南京-马鞍山双雷达、广州-深圳双雷达),及2010年-项目在研四年期间南京-马鞍山、广州-深圳、宁波-舟山、上海双雷达等观测的飑线数据,进行双多普勒雷达三维风场反演；然后结合自动气象站加密数据、探空资料、气象卫星资料及NCEP资料，综合使用单雷达回波强度分析、径向速度分析、组网雷达三维拼图技术,重点使用双雷达三维风场反演数据研究飑线中尺度三维精细结构和演变特征。研究飑线在形成、发展、减弱、消亡整个生命史过程中结构及演变特征、降水和大风的时空分布等,飑线内部冰雹、强降水等强对流系统的结构,飑线系统三维气流分布、演变特征及其与飑线发展的关系;研究飑线成熟阶段对流区、后部层状云区入流和出流的空间分布特征;对比分析华北、江淮和华南飑线三维结构差异,建立华北、江淮和华南飑线中尺度精细动力结构模型。

飑线是中尺度对流系统的一种重要组织形式，经常造成雷暴、大风、冰雹和强降水等强对流天气，对飑线的中尺度结构开展深入研究，不仅可以加深对飑线形成机理和结构特征的认识，对提高飑线的短时临近预报也具有重要科学意义。. 本项目对华南、江淮和华北地区的四个飑线的双多普勒天气雷达时间同步观测数据进行三维风场反演，同时结合自动气象站加密数据、探空资料、气象卫星资料及NCEP资料，综合使用单雷达回波强度分析、径向速度分析、组网雷达三维拼图技术，重点使用双雷达三维风场反演数据，研究飑线中尺度三维精细结构和演变特征；并在此基础上，分别建立了华南、江淮和华北飑线成熟阶段的中尺度三维精细结构概念模型。. 本项目研究成果揭示，地面辐合线是飑线对流带形成的重要原因之一；飑线前沿中层在多普勒雷达风场上具有明显的中层径向辐合特征，其位置基本对应于飑线强回波区，中层径向辐合对于飑线对流线的形成具有重要作用；飑线对流云区内部的对流单体触发局地强降水。同时，还研究了华南飑线、江淮飑线和华北飑线中尺度三维结构的共性和差异。双雷达反演的风场揭示飑线低层前缘有自前向后的入流；对流区前沿不仅是大风区，而且还是水汽辐合上升运动区，从而形成飑线的强降水区；层状云区低层则盛行自后向前的入流；对流云区和层状云区的中层均盛行一致的自前向后的气流。在沿着飑线移动方向的垂直剖面内，自后向前的气流由层状云低层进入飑线；自前向后的气流从对流线中低层进入飑线对流云区、在中高层分成两支气流，一支气流流向前部、另一支则流向层状云区。分析结果揭示，天气尺度背景场、大气热力和动力条件的差异，是造成三类飑线结构有着重要区别的原因。华南飑线在空间尺度、持续时间、相对风暴的风速、对流活跃强度、造成的局地强降水等方面均明显强于其他两类飑线。本项目研究结果进一步加深了对飑线形成机理和三维结构的认识，对于飑线的短时临近预报也具有重要参考价值。