The Comparison Of The Structure Features Of Two Linear MCS Triggering Rainstorm In Jianghuai Region

Based on the high spatial and temporal surface observational data, soundingdata, Doppler radar data, retrieval wind data of radar observation and NCEPreanalysis data, the weather background, the evolution and structure of two MCSsthat occurred over the Jianghuai region on6July2009are investigated. Oneof the MCSs is the TS(tailing stratiform) archetype, the other one is thePS(parallel stratiform) archetype. The TS MCS is ahead of500hPa trough, theother one is rearward of500hPa trough. In the region which the convection forms,the atmosphere is the cold and dry air over the warm. The TS MCS is stimulatedby surface wind convergence, and the PS MCS is stimulated by small scale lowerpressure system. Before the TS MCS formed there is a moist neutral stratificationstructure at low level, and unstable stratification at middle level. The PS MCShas a unstable stratification at low level and stable stratification at middlelevel. At the mature stage, mesohigh and cold pool are obvious in both of thesystems with different position. The TS MCS s mesohigh is ahead of cold pool.The PS MCS s mesohigh and cold pool are each approximately. Cold pool promoteand maintain both of the systems. Based on the retrieved wind field, the TS MCSexhibits negative line-perpendicular storm-relative winds at low levels. Thereis rear inflow and meso-γ bookend vortices along the TS MCS at middle levels.The PS MCS exhibits line-parallel storm-relative flow at low and mid-to-upperlevels. Rear inflow and bookend vortices plays an essential role in the formationof this bowing structure. At the mature stage, the tailing system develops withupdraft in the mid-to-upper-levels and downdraft in the low level of thestratiform region. The parallel system develops with downdraft in the wholelevels of the statiform cloud. The formation of the stratiform cloud and verticalmotion are closely related to the rear inflow. Their stratiform regions are alsodifferent. The stratiform region is associated with the dissipation of convective region and horizontal wind relative to the system.