摘要
利用高低空观测资料、多普勒雷达资料和NCEP再分析资料,分析了2009年8月18～20日辽宁的局部大暴雨的天气过程。结果表明,贝加尔湖切断低涡中短波槽分裂东移,引导冷空气东移南下,与副高西侧西南风引导西南暖湿气流北上,在华北、东北地区相遇,辽宁位于低层气旋东南象限。此次降水时间演变和空间分布上都具有明显的中尺度特征;低空急流和超低空急流使辽宁底层水汽通量辐合,为暴雨提供充足的水汽;中层干冷空气侵入,致使大气层结处于对流不稳定状态;低层正涡度和高层负涡度强度同时加大,抽吸作用明显,触发了对流运动的发生和维持。
Based on the high and low altitude observed data,Doppler Radar and NCEP reanalysis data,the weather process of the local heavy rainstorm from August 18,2009 to August 20,2009 in Liaoning was analyzed.The analysis showed that the short-wave trough of Lake Baikal cut-off low splits moved eastward,which guided the cold air to the southward.The southwest wind in the west of subtropical high guided the southwest warm and humid air to the northward.Two airstreams met at the Northeast and North China.Liaoning Province was located in the southeast quadrant of the lower cyclone.The evolution and spatial distribution of precipitation had significant mesoscale features.Low-level jet and the ultra-low-level jet made the bottom water vapor flux converge,which provided adequate water vapor for the storm.The inrush of arid cold air on middle levels resulted in the convective and unstable energy accumulation of the atmosphere.The intensity of the lower-level convergence,upper-level divergence was increased,which triggered the genesis,development and maintaining of convection.
出处
《安徽农业科学》
CAS
北大核心
2010年第12期6317-6320,6352,共5页
Journal of Anhui Agricultural Sciences
关键词
大暴雨
中尺度分析
超低空急流
Heavy rainstorm
Mesoscale analysis
Ultra-low-level jet
