摘要
用多种加密观测资料和NCEP日再分析资料分析了2010年7月14日强降水期间咸宁地区一次非线状MCS活动造成短时强降水的发生发展机制。结果表明,14日13—18时非线状MCS回波结构组织性差,强对流单体散乱地分布在大片层状回波中,准静止地维持在湖北咸宁地区大约5 h,造成了短时强降水。该MCS发生在梅雨锋锋面附近的地面涡旋环流中,高空冷空气侵入和锋前抬升运动是对流的主要触发机制,切变线南侧不稳定的暖湿气流在长江中游地区辐合集中、局地的地面气流辐合和边界层有利的风切变是该非线状MCS发展维持在咸宁地区的有利条件。高时空分辨率探测资料对MCS演变过程有较好的分析能力。
Using multiple intensified observation data and NCEP daily reanalysis data, the development mechanism of a nonlinear mesoscale convective system （MCS） that caused a short-time severe rainfall in Xianning City on 14 July 2010 is analyzed. The results show that the organization of nonlinear MCS is poor during 13：00--18：00 BT 14 July 2010. The strong convective cells are disorderly distributed in big strati- form echoes, keeping the quasi-stationary front staying over Xianning about 5 h, and thus leading to the short time severe precipitation in Xianning. The nonlinear MCS generates in a surface vortex circulation near Meiyu front, and the convections are triggered primarily by upper cold air and lifting motion in front of the front. The favorite ambient conditions for the nonlinear MCS to maintain and develop are the con- vergence and concentration of unstable warm moist airflow on the southern side of the shear line over the middle reaches of Yangtze River, the mesosacle convergence of surface local airflow and the favorable wind shear of boundary layer. In general, the high spatial-temporal resolution observation data can be well ap- plied in analyzing the MCS evolution process.
出处
《气象》
CSCD
北大核心
2013年第5期556-566,共11页
Meteorological Monthly
基金
国家自然科学基金项目(40930951和41105072)
灾害天气国家重点实验室开放课题(2010LASW-A04)
公益性行业(气象)科研专项(GYHY201106003和GYHY200906010)
科技部科研业务项目(1101和1201)课题共同资助
关键词
加密观测资料
梅雨锋
中尺度对流系统
发展机制
intensive observation data, Meiyu front, mesoscale convective systems （MCS）, developmentmechanism
