[Objective] The research aimed to analyze formation reason of the ' 7.28' regional rainstorm in Zhongwei City.[Method] NCEP /NCAR reanalysis data and Micaps routine data were used to analyze formation reason o...[Objective] The research aimed to analyze formation reason of the ' 7.28' regional rainstorm in Zhongwei City.[Method] NCEP /NCAR reanalysis data and Micaps routine data were used to analyze formation reason of the regional rainstorm in Zhongwei City on July 28,2011.[Result]Under the east-high-west-low circulation situation,factors which caused this rainstorm included westerly jet at 200 hPa,cold trough at 500 hPa,low vortex and shear line at 700 hPa,quick alternation of the warm and cold airs at 850 hPa,stable northward movement of the subtropical high.Falling zone of the rainstorm was located at the right of the upper jet,the left of the low-level jet and the south of 700 hPa shear line.Analyses on the each physical quantity field showed that water vapor condition,vertical motion,energy,vorticity,divergence and wind field distribution over the rainstorm area were all beneficial for rainstorm generation.When the rainstorm occurred,radar echo mainly presented as mixed-cloud precipitation type.The echo intensity was from 30 to 45 dBz,and top height of the echo was from 7 to 8 km.[Conclusion]The research provided some experiences and theoretical guidance for future rainstorm forecast in Zhongwei City.展开更多
文摘[Objective] The research aimed to analyze formation reason of the ' 7.28' regional rainstorm in Zhongwei City.[Method] NCEP /NCAR reanalysis data and Micaps routine data were used to analyze formation reason of the regional rainstorm in Zhongwei City on July 28,2011.[Result]Under the east-high-west-low circulation situation,factors which caused this rainstorm included westerly jet at 200 hPa,cold trough at 500 hPa,low vortex and shear line at 700 hPa,quick alternation of the warm and cold airs at 850 hPa,stable northward movement of the subtropical high.Falling zone of the rainstorm was located at the right of the upper jet,the left of the low-level jet and the south of 700 hPa shear line.Analyses on the each physical quantity field showed that water vapor condition,vertical motion,energy,vorticity,divergence and wind field distribution over the rainstorm area were all beneficial for rainstorm generation.When the rainstorm occurred,radar echo mainly presented as mixed-cloud precipitation type.The echo intensity was from 30 to 45 dBz,and top height of the echo was from 7 to 8 km.[Conclusion]The research provided some experiences and theoretical guidance for future rainstorm forecast in Zhongwei City.
