摘要
利用常规资料、多普勒雷达回波资料和数值模拟结果对2004年8月3日辽东半岛大暴雨进行了中尺度分析,并应用湿位涡理论对此次过程进行了诊断。结果表明:产生本次大暴雨的中尺度系统是低空急流、切变线和中尺度低压。雷达观测的中γ尺度回波、带中带回波、中尺度气旋、低空急流和弓状回波均产生了对流性强降水。数值模拟结果分析表明:低空急流及高低空急流两次不同方式的耦合形成的强烈上升运动对大暴雨有重要贡献。等熵面由水平变为陡立且密集导致湿斜压涡度的激烈增长,促使降水增幅。低层强对流不稳定和斜压不稳定为这次大暴雨的发生提供了条件。
Based on the routine meteorological observations, Doppler radar data and the numerical simulation outputs, a mesoscale analysis of a torrential rain event over Liaodong Peninsula on 3 August 2004 is made. And a diagnosis of the event is made by using the theory of moist potential vorticity. The results show that the mesoscale systems causing the torrential rain are a low level jet （LLJ）, a shear line and a mesoscale depression. The meso- γ scale echoes, band-in-band echo, mesoscale cyclone, LLJ and bow echo detected by Doppler radar cause strong convective rainfall. The analysis of simulation outputs indicates that LLJ and the two different upper level jet-LLJ couplings made an important contribution to the torrential rain by producing strong ascending motion. The horizontal moist isentropes turning to very stiff and dense state led to the development of moist slantwise vorticity and the arnplification of the precipitation. The strong convective instability and the baroclinic instability in the low level provided the conditions of the torrential rain.
出处
《气象》
CSCD
北大核心
2007年第6期44-50,共7页
Meteorological Monthly
基金
国家自然科学基金项目(40405009
40075009
40205008)
国家重点基础研究发展规划项目2004CB418301
关键词
大暴雨
中尺度分析
雷达回波
数值模拟
湿位涡
torrential rain mesoscale analysis radar echo numerical simulation moist potential vorticity
