冷空气对台风“海葵”(1211)倒槽特大暴雨作用分析  

ANALYSIS ON THE FUNCTIONS OF COLD AIR IN A SUPER HEAVY RAINFALL CAUSED BY A REVERSE TROUGH OF TYPHOON HAIKUI(1211)

作　　者：吴海英[1,2] 陈海山[1] 曾明剑[2] 刘安宁[2] 王伟丽[2] 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]江苏省气象台,江苏南京210008

出　　处：《热带气象学报》2014年第5期871-880,共10页Journal of Tropical Meteorology

基　　金：江苏省科技厅自然基金项目(BK20131459);江苏省科技厅社会发展项目(BE2011818);公益性行业(气象)科研专项(GYHY201306010)共同资助

摘　　要：针对2012年8月10日发生在台风"海葵"(1211)减弱低压倒槽顶部的特大暴雨过程,利用加密自动气象站、卫星云图、NCEP再分析资料,结合中尺度数值模式的模拟结果,分析了这次特大暴雨期间的中尺度对流系统演变特征及形成机理。研究表明,东北冷涡后部南下的冷空气为特大暴雨的发生提供了有利的热动力条件,促进了降水的发展。冷空气主体偏北,仅从对流层中层侵入低压倒槽北部,而对流层低层并无明显冷空气影响,使暴雨区上空形成冷平流叠置于暖平流之上的温度平流垂直分布结构,促进这一地区对流不稳定层结的建立和发展。冷空气与低压倒槽内辐合上升的暖湿空气对峙于对流层中层,引起中层锋生,锋生效应使风场辐合加强,进一步促进锋生。两者相互作用促进暴雨区及附近的中小尺度对流系统发展,在暴雨区上空强迫出一支对流尺度的强上升气流,加强低层水汽向上输送,使暴雨区上空水汽辐合层迅速增厚,从而引发局地特大暴雨天气发生。Based on intensive automatic weather station data,satellite cloud imagery and NCEP reanalysis data and simulation results with a mesoscale numerical model,a super heavy rainfall that occurred on top of a decreasing trough from typhoon Haikui （1211） is studied.For the mesoscale convective systems,the evolution characteristics and their formation mechanisms are analyzed in detail.The results show that cold air from the rear of a northeast cold vortex invading the north of a reversed trough is dynamically and thermally advantageous and enhances the precipitation.The main cold air is northerly located so that the cold air invades only the middle level of the periphery of the reversed trough.The structure of cold advection overlaying warm advection is favorable for unstable atmospheric stratification.In the middle troposphere cold air meets warm and wet airflow ascending from the reverse trough,resulting in frontogenesis.Interactions between frontogenesis and wind convergence leads to the development of mesoscale convective systems and a strong convective scale updraft in the rainstorm region and its vicinity,which strengthens the upward transportation of water vapor from low levels and the thickening of water vapor convergence and results in local super heavy rainfall.

关 键 词：特大暴雨 冷空气 锋生作用 中尺度对流系统 

分 类 号：P426.62[天文地球—大气科学及气象学]