Diagnostic Analysis on Local Rainstorm Processes in Southwest Slope of Shennongjia Forest Region

Zhang Fulin; Pi Ting; Zhang Lijun

doi:10.16765/j.cnki.1673-7148.2017.02.016

Abstract：Shennongjia southwest slope is a rainstorm disaster prone area.In this paper,by using the conventional data,Doppler radar data and regional automatic weather station data,the analysis is made on the synoptic background and structure characteristics of the mesoscale convective system (MCS) during continuous two short time rainstorm processes in southwest slope of Shennongjia from August 6th to 7th night 2014,the amplification of Shennongjia mountain complex terrain structure on the southwest slope rainfall is discussed.The results are as follows.1)While the high-level weather system force is weak,ground warm trough on the edge of the subtropical high and 850 hPa cyclone bending area and the convergence developments may be the triggering systems which cause this kind local strong precipitation weather,invasion of weak cold air in the ground is conducive to the maintain and strengthen of rain.2) The two local rainstorm processes both occurred under the influence of meso-β scale convective system,with short rainfall duration,high intensity,little moving and obvious MCS characteristics,belonged in the leading stratiform cloud and trailing stratiform cloud MCS types,respectively.3)The first rainstorm was based on convective precipitation,with stronger reflectivity,the second rainstorm process was with lower centroid and stratiform cloud more prominent,maintained relatively longer time,and its precipitation efficiency was higher.4)The Shennongjia southwest is a steeply slope with high altitude.The dynamic lifting and convergence effect of terrain can enhance the upward motion.Significant terrain forced lifting effect not only has important roles on the local convection triggering,precipitation increasing,also has effect on the MCS structure,which might be one of the most important reasons for the high occurrence of Shennongjia southwest slope rainstorm.