摘要
利用Micaps常规观测资料、自动站加密观测资料、NCEP再分析资料和GOES卫星资料,从环流背景、水汽条件、动力条件、不稳定机制等方面,重点对2008年7月22日襄樊罕见特大暴雨的中尺度观测特征与物理机制进行分析。结果表明:此次特大暴雨是在副热带高压、高空槽、西南低涡、切变线和地面倒槽的共同作用下发生的;切变线上对流云团在暴雨区合并、加强是造成襄樊罕见特大暴雨天气的直接原因,强降水发生在TBB低值中心;沿低空急流建立的从南海到华中地区的水汽通道,为暴雨发生发展直接输送暖湿空气;低层强烈的水汽输送和水汽辐合使暴雨区大气湿层迅速增厚,为暴雨发生发展提供了有利的水汽条件;低层辐合、高层辐散和整层正涡度的配置以及强的垂直上升运动,为暴雨发生提供了动力条件;能量锋锋生、湿度锋锋生对中尺度对流系统发生发展具有触发作用。
Using the Micaps conventional observations, encryption data at the automatic weather stations, NCEP rcanalysis data and GOES satellite data, the causes of Xiangfan rare heavy rainfall on July 22, 2008 are analyzed on the circulation, water vapor condition, kinetic condition and the instability mechanism. The results show that： the heavy rainfall happens under the together conditions including the subtropical high, upper air trough, southwest vortex, the shear line and the ground reverse trough; the convective clouds at the shear line combining and strengthening in the area of heavy rain is the direct cause for the rare torrential rain occurring in Xiangfan. The heavy rainfall occurred at the low value center of TBB. Established by low-level jet, the water vapor channel from the South China Sea to the inland region provides the adequate moisture. The low level intense water-vapor transfer and convergence incrassating the humidity level rapidly to provide the advantageous water vapor. The high-level negative vorticity, the stacking middle and low level positive vorticity and the intense vertical ascent movement are the dynamic conditions. The energy front frontogenesis and the humidity front frontogenesis trigger and develop the mesoscale convection system.
出处
《暴雨灾害》
2009年第1期43-50,共8页
Torrential Rain and Disasters
关键词
特大暴雨
高空槽
西南低涡
低空急流
湿度锋锋生
Rare Torrential Rain
Upper air trough
southwest low vortex
Low altitude jet stream
Humidity front frontogenesis
