气象学报2022，Vol.80Issue(5)：748-764,17.DOI:10.11676/qxxb2022.060
副热带高压背景下极端短时强降水的双偏振相控阵雷达观测分析
Analysis of an extreme flash rain event under the background of subtropical high based on dual-polarization phased array radar observations
摘要
Abstract
An extreme flash rain event that occurred in Xiamen under the background of subtropical high on 11 August 2021 is analyzed based on X-band dual-polarization phased array radar observations. Dynamic and microphysical characteristics of the precipitation system are analyzed using the Doppler radar wind field retrieval technique combined with high-precision topographic data. The study yields the following results. (1) The event took place under the control of the subtropical high with the characteristics of weak synoptic-scale forcing. The surface wind convergence line promoted the formation of a quasi-linear convective system (QLCS), and the back-building process of the QLCS led to local extreme precipitation event. (2) The updraft lifted the raindrops to the mid-level, forming a large particle accumulation layer. When it descended, the rain intensified. The configuration of inclined updraft and downdraft ensured that the falling of large particles would not suppress updraft, which is favorable for the development and maintenance of convective system. The downdraft triggered the development of the upstream convective system, forming a back-building process. (3) The impact of local terrain on the precipitation system was highlighted under the weak synoptic scalebackground. The low-level convergence induced by local terrain caused the polarization parameters such as differential reflectivity (ZDR) and specific differential phase (KDP) to increase significantly on the windward slope, and the large value area was maintained there. The larger denser precipitation particles produced extremely high precipitation efficiency. (4) The warm rain process and the ice phase process coexisted in this extreme precipitation event. The warm rain process played a major role in the formation of rain, and the melting of ice particles accelerated this process. (5) At high rain rate, the breakage and collision of raindrops tend to balance, and the increase of rain rate depends on the increase of raindrop concentration. Therefore, ZDR can be used to determine whether the rain rate is increasing. (6) The evolution of the ZDR and KDP column is an appropriate index that can reflect the development of the surface rain rate. During a continuous precipitation process, the re-development of the ZDR (KDP) column height occurs earlier than that of the precipitation system.关键词
双偏振相控阵雷达/极端短时强降水/弱天气尺度背景/地形降水Key words
Dual-polarization phased array radar/Extreme flash rain/Weak synoptic-scale background/Orographic precipitation分类
天文与地球科学引用本文复制引用
潘佳文,彭婕,魏鸣,郑秀云,吴伟杰,高珊,吴举秀,蔡菁..副热带高压背景下极端短时强降水的双偏振相控阵雷达观测分析[J].气象学报,2022,80(5):748-764,17.基金项目
福建省自然科学基金项目（2021J01450、2021J01465、2022J011080）、山东省自然科学基金项目（ZR2020MD052）、福建省气象局开放式基金项目（2021KXM02）、厦门市社会发展领域指导性项目（3502Z20214ZD4005）。 （）
