席乐,闵锦忠,王仕奇.一次华南强飑线过程的数值模拟及后方入流作用诊断.气象科学,2018,(6):739-748 XI Le,MIN Jinzhong,WANG Shiqi.Numerical simulation and rear inflow jets diagnostic analysis of a strong squall line process in South China.Journal of the Meteorological Sciences,2018,(6):739-748
一次华南强飑线过程的数值模拟及后方入流作用诊断
Numerical simulation and rear inflow jets diagnostic analysis of a strong squall line process in South China
投稿时间:2018-03-01  修订日期:2018-03-26
DOI:10.3969/2018jms.0035
中文关键词:  飑线  数值模拟  弓形回波  后方入流  涡旋
英文关键词:Squall line  Numerical simulation  Bow echo  Rear inflow jets  Vortex
基金项目:国家重点研发计划(2017YFC1502103);国家自然科学基金重点资助项目(41430427)
作者单位E-mail
席乐 南京信息工程大学 气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室, 南京 210044  
闵锦忠 南京信息工程大学 气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室, 南京 210044 minjz@nuist.edu.cn 
王仕奇 南京信息工程大学 气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室, 南京 210044  
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中文摘要:
      利用WRF中尺度模式对2014年3月30-31日发生在华南的一次强飑线过程进行数值模拟。本次飑线过程受高空槽和低涡切变线影响,水汽条件充足,低层垂直风切变较强。模拟结果表明:发展阶段,后方入流缺口开始出现,飑线逐渐呈弓形结构;成熟阶段,飑线后方入流逐渐下沉到地面并延伸至对流区前沿,冷池完全移入残留冷区并加强,配合九连山下坡过程,飑线得以加强。后方入流对本次飑线过程的发展和维持十分重要。后方入流受环境风及中层负压力扰动作用开始形成,随后受对流区后侧中低层涡旋对的影响迅速发展增强而进入发展阶段,反气旋式涡旋的北侧风场促进了后方入流的形成和发展;成熟阶段,气旋式涡旋的南侧风场使后方入流迅速增强。气旋式涡旋区域主要受涡管拉伸作用增长,反气旋式涡旋区主要受涡度倾斜增长作用。涡旋对垂直涡度主要是由低层水平涡度向上倾斜引起,而水平涡度则是由斜压作用产生。
英文摘要:
      The WRF mesoscale model is used to simulate the process of a strong squall line occurring in South China from March 30 to 31, 2014. The squall line process is affected by the high-altitude trough and the low-vortex shear line, the water vapor conditions are sufficient, and the low-level vertical wind shear is strong. Results show:in the development stage, the rear inflow gap begins to appear, and the squall line gradually becomes an arched structure; at the maturity stage, the inflow from the rear of the squall line gradually sinks to the ground and extends to the front of the convective zone. The cold pool is completely moved into the residual cold zone and strengthened. With the Jiulianshan Mountain downhill process, the squall line is strengthened. The Rear Inflow Jets(RIJ) are very important for the development and maintenance of this squall line process. The rear inflow jets are formed by the ambient wind and the middle layer negative pressure disturbance action, and then rapidly developed and enhanced under the influence of the middle and lower layer vortex pairs on the back side of the convection zone. In the development stage, the north wind field of the anticyclonic vortex promotes the formation and development of the rear inflow jets; at the maturity stage, the south side wind field of the cyclonic vortex rapidly increases the rear inflow jets. The cyclonic vortex is mainly increased due to effect of the stretching term, while the anticyclonic vortex is mainly increased due to effect of the tilting term. The vertical vorticity of the vortex pairs is mainly caused by the upward tilt of the low level horizontal vorticity which is caused by the baroclinic term.
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