摘要
利用美国国家环境预报中心再分析资料、1h一次的华南降水资料以及局地分析预报系统再分析资料,对2008年6月11日20时—13日20时发生在广西的一次大暴雨个例进行了诊断分析.结果表明:高低空急流、西南涡以及从低涡中心延伸出的切变线是这场暴雨的主要影响系统.广西强降水主要位于高空急流的右后方、低空急流的左侧、西南涡的底部至底后部以及切变线附近,强降水中心随影响系统的东移而东移,降水随着西南涡的加强而加强.该暴雨过程中西南涡在700hPa为暖心结构,正涡度区域垂直向上伸展,整个对流层都为正涡度,低层辐合高层辐散的配置有利于对流的发展,强降水的极值中心上空对应着较强的上升运动.水平涡度平流项和水平涡度辐散项作用相反,水平辐散项在对流层低层对总涡度起直接作用且为正贡献,对流层中高层主要是垂直平流项和扭转项起主要作用.
Based on NCEP 1°× 1° re-analysis data, hourly precipitation data and LAPS 0. 045 °×0. 045 ° re-analysis data, a severe heavy rain event that occurred in Guangxi Province at 20 ： 00 on June 11,2008 to 20 ： 00 on the 13th was analyzed. The high and low level jet, the southwest vortex and the shear line extending from the vortex center were the main systems of the rainfall. The heavy rain event mainly occurred in the right-rear area of the high-level jet, on the left side of the low-level jet, at the bottom to the rear of the vortex and near the shear line. The heavy rainfall center moved toward the east with the eastward shifting of the systems. Precipitation increased with the strengthening of the southwest vortex. During the heavy rainfall the southwest vortex had the warm core at 700 hPa. The positive vorticity region extended vertically upward, and the entire troposphere took on positive vorticity. The lower-level convergence and upper-level divergence were favorable for the development of convection. The upward motion was strong over the strong precipitation center. In the vorticity budget equation, the horizontal vorticity advection was playing a role opposite to the horizontal vorticity diversion which had the direct function and made positive contributions in the total vorticity field in the lower troposphere. The vertical advection and the twisting term played the main role in the middle and upper troposphere.
出处
《南京信息工程大学学报（自然科学版）》
CAS
2010年第1期40-50,共11页
Journal of Nanjing University of Information Science & Technology（Natural Science Edition）
基金
江苏省"六大人才高峰"培养对象资助(07-A-012)
国家重点基础研究发展计划(2004CB418301)
关键词
西南低涡
暴雨
诊断分析
涡度
收支
southwest vortex
heavy rainfall
diagnoses
vorticity budget
