我国东南沿海冬季渐近线形锋生辐合线及其强降水热力发展机制研究
投稿时间:2019-05-07  修订日期:2019-05-24  点此下载全文
引用本文:
摘要点击次数: 73
全文下载次数: 0
作者单位E-mail
王坚红 南京信息工程大学海洋科学学院 1597706505@qq.com 
曲梓祎 南京信息工程大学海洋科学学院  
李洪利 南京信息工程大学海洋科学学院  
黄志刚 福建气象服务中心  
张翠艳 锦州市气象局,  
苗春生 南京信大气象科技研究院  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:基于我国东南沿海冬季强降水的统计分析,采用 EOF、REOF、North检验等方法对2011—2016年12月、1月、2月欧洲中心的冬季降水资料进行分类,选取位于内陆的REOF第1、第4两个模态,分别对两模态的降水样本进行合成分析,它们的降水中心与福建多年统计的暴雨中心相符合。与强降水配合在1000hPa层上,有自北向南的渐近线型辐合气流,并有锋区配合,形成天气尺度渐近线型锋生辐合线,强降水均位于辐合轴线左侧气旋式风切变处。这是一类以往未有具体讨论的东南沿海地区的冬季暴雨系统。通过客观判定方法以及建立系统坐标系,确认并诊断该系统的结构。在较为冷干少雨,低层盛行偏北风的冬季,此类系统结合了锋区热力抬升与辐合气流动力抬升,增强雨区上升运动;同时通过辐合线风分量将临近的海面水汽汇集到降水区,与中高层副高边缘偏南气流相向而行,构成较为深厚的水汽输送层;通过非绝热加热,形成深厚的热力对流不稳定。,并通过干区向湿气团下楔入,形成下干上湿的湿动力不稳定。,以及假相当位温随高度增加而递减,形成上暖湿下冷干的对流不稳定层,因此,该系统影响着冬季强降水的发生发展及落区。通过WRF模式的模拟进行环境热力机制影响探讨。,结果显示,凝结潜热加热可影响辐合线的辐合位置与强度、锋生区的位置及强度,进而影响系统的活跃。中层潜热加热,抑制平流感热冷却进入暖气团,维持降雨区热力不稳定及降水强度。渐近线型锋生辐合线有利于造成东南沿海冬季大范围降水中出现暴雨。其中凝结潜热释放具有重要贡献。
中文关键词:东南沿海冬季强降水  渐近线型锋生辐合线  数值模拟  热动力机制
 
A Study on the Thermodynamic Mechanism of Asymptotic Frontogenesis Convergence Line and its Strong Rainfall on the Southeast Coast
Abstract:Based on the statistical analysis of heavy precipitation in the west coast of the Taiwan Strait, the winter precipitation data of the European Center in December, January and February 2011-2016 were classified by EOF, REOF and North test, and the REOF mode1 and mode 4 located in the inland were selected. The two-mode precipitation samples were synthesized analyzed respectively,and their precipitation centers were consistent with the rainstorm centers of many years in Fujian. On 1000hpa , there is an asymptotic convergence flow from north to south with a front zone, this forms an asymptotic frontogenesis convergence line with synoptic scale. The strong precipitation is usually located on the left side of the convergence axis where wind with cyclonic shears. This is a type of winter rainstorm system in the southeastern coastal areas that has not been specifically discussed in the past. The structure of the system is confirmed and diagnosed by an objective determination method and establishing a system coordinate system. In the winter when it is relatively cold and dry, and the low-level is prevailing in the northerly wind, such a system combines the thermal lift of the front zone and the dynamic uplift of the convergent airflow to enhance the ascending motion of the rain zone; At the same time, the vapor from adjacent sea surface is collected into the precipitation area by transfer of wind component of convergence line, combined the southerly airflow at the middle and upper levels from subtropic high west edges, they form into a relatively deep vapor transport layer. By non-adiabatic heating, a deep thermal convection unstable is formed. By dry zone wedges under the wet air mass,the wet dynamic instability is formed through the environment of wet upper and dry beneath, and the pseudo-equivalent temperature decreases with height, it forms a convective unstable of cold and dry under warm and wet environment Therefore, the system affects the occurrence and development of heavy precipitation in winter. The influence of environmental thermal mechanism is investigated through the simulation of WRF mode. The results show that the latent heat of condensation can affect the convergence position and strength of the convergence line, the position and strength of the frontal zone, and thus affect the activity of the system. The middle levels is heated by latent heat to inhibit sensible heat cooling into the warm air mass and maintain the thermal instability and precipitation intensity in the rainfall area.The asymptotic frontogenesis convergence line is conducive to the occurrence of heavy rain in the large-scale precipitation during winter in Fujian. In the situation the latent heat release of condensate has an important contribution. The topographical effects of this low-level system will be discussed in detail in another paper.
keywords:winter heavy precipitation in Southeastern Coast  asymptotic frontogenesis convergence line  numerical simulation  thermal dynamic mechanism  
  查看/发表评论  下载PDF阅读器