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基于雷达资料四维变分同化和三维云模式对一次超级单体风暴发展维持热动力机制的模拟分析
引用本文:陈明轩,王迎春,肖现,高峰.基于雷达资料四维变分同化和三维云模式对一次超级单体风暴发展维持热动力机制的模拟分析[J].大气科学,2012,36(5):929-944.
作者姓名:陈明轩  王迎春  肖现  高峰
作者单位:1.中国气象局北京城市气象研究所,北京 100089
基金项目:公益性行业 (气象) 科研专项项目GYHY200706004,国家科技支撑计划课题2008BAC37B03,北京市科技计划课题Z090506016609001
摘    要:利用三维云尺度数值模式和雷达资料快速更新循环四维变分同化(4DVar)技术,对京津冀地区一次强降水超级单体风暴发展演变的热动力机制进行了数值模拟和结果分析,并结合雷达、加密探空和自动站资料,揭示了快速变化的近风暴大气环境及风暴自身的热动力三维特征对超级单体形成、发展和演变的影响.雷达回波观测分析表明,这是一次由多单体合...

关 键 词:雷达资料  4DVar  云模式  超级单体  热动力机制
收稿时间:2011/7/25 0:00:00
修稿时间:2012/3/16 0:00:00

A Case Simulation Analysis on Thermodynamical Mechanism of Supercell Storm Development Using 3-D Cloud Model and 4-D Variational Assimilation on Radar Data
CHEN Mingxuan,WANG Yingchun,XIAO Xian and GAO Feng.A Case Simulation Analysis on Thermodynamical Mechanism of Supercell Storm Development Using 3-D Cloud Model and 4-D Variational Assimilation on Radar Data[J].Chinese Journal of Atmospheric Sciences,2012,36(5):929-944.
Authors:CHEN Mingxuan  WANG Yingchun  XIAO Xian and GAO Feng
Institution:1.Institute of Urban Meteorology, China Meteorological Administration, Beijing 1000892.Beijing Meteorological Service, Beijing 100089
Abstract:A numerical simulation on thermodynamical mechanism of a heavy precipitation supercell development in Beijing-Tianjin-Hebei area is implemented by using a three-dimensional cloud-scale numerical model and rapid update cycling 4-D variational assimilation (4DVar) technique of radar data. The analysis on the simulation results and observations of radars, rawinsondes, and Automatic Weather Stations (AWSs) denotes the effects of frequent variational 3-D thermodynamical attribute of storm and storm-relative environment on initiation, intensification, and development of the supercell. The analysis on radar observations indicates the supercell storm with right-moving property evolves from multi-cell storms merging and splits into multi-cell storms again. The simulation results show low-and middle-layer vertical wind shears gradually intensify in the front of the storm that is favorable to form quasi-steady, strongly rotating updraft and mesocyclone in the supercell storm during the period of the supercell initiation and enhancement. The hodographs analyzed by simulated winds indicate the low-level vertical wind shear has significant clockwise-curved attribute in front of storm that is favorable to strengthening and right-moving of the supercell. The simulation also reveals that the cold pool, convergence of outflow (gust front) and low-level wind, and updraft ahead of the supercell continually strengthen along with the storm development, which results in warm and moist low-layer air ascending ahead of the storm continuously. The ascending air revolves into storm under the impact of strong vertical wind shear that maintains and strengthens the supercell storm. During the period of the supercell dissipation and split, the simulation results indicate that all of thermodynamical structures are unfavorable to further development of the supercell. The vertical wind shear weakens evidently and contributes a unidirectional (straight) hodograph that is only conformable to multicell storms. The perturbation temperature shows that the cold pool further intensifies and expands with greater speed than the storm motion during the period. The low-layer winds indicate the outflow boundary (gust front) becomes much intense and forward, and is away from the storm. The low-level convergence and updraft are also weaker during the period than those during the period of the supercell enhancement. The storm-relative environment helicity (SREH), storm bulk Richardson number (SBRN), and storm strength (SS) are calculated by using the simulated data. The results indicate SREH<150 m2/s2, SBRN<45, and SS>0.4 during the period of the supercell initiation and enhancement, and the reversed conclusion during the period of the supercell dissipation and split. The coincident conclusion with other investigations implies the simulated SREH, SBRN, and SS are significant to indicate development of the storm case.
Keywords:radar data  4DVar  cloud model  supercell  thermodynamical mechanism
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