Cause Analysis of Severe Convection over Xinxiang on 14 July,2014

Ma Yuezhi; Su Aifang; Ye Dong; Liu Wei

doi:10.16765/j.cnki.1673-7148.2017.01.008

Abstract：Based on the conventional observation data,meteorological data from regional automatic weather stations,satellite data,Doppler radar data and NCEP reanalysis data,the severe convection over Xinxiang on 14 July,2014 was analyzed.The result showed that the upper eastward cold trough and the lower warm ridge overlaying attributed the strong instability of atmospheric stratification.The mid-lower warm moist atmosphere moved northward obviously and developed to upper level in the afternoon.The atmospheric convective instability was significantly enhanced,which was favorable to the occurrence of thunderstorm gale and strong convective weather.Before the severe convection occurred,the vertical wind shear from 0 km to 6 km had the moderate to strong level,which is conducive to the formation and mainte nance of convective systems.The surface mesoscale convergence line activated the severe convection.The convective cloud cluster in front of the surface convergence line tail developed stronger and faster.The merge of convective cloud clusters leaded to the rapid strengthening of convective cloud clusters.The merging of convective cells benefited the growth spurt of convective echo and rapid uplift of echo top height.The thunderstorm outflow boundary was an important triggering mechanism of the severe convective weath er.The thunderstorm outflow boundary uplifted by the east of Taihang Mountains triggered large-scale dispersive convective cells,which resulted in short-time strong rainfall.Gale were mainly caused by downburst in multi-cell storm and thunderstorm outflow boundary,while the wind caused by downburst is much stronger than that caused by thunderstorm outflow boundary.The rapidly increase of echo center,center height,echo top height and VIL value had very good instruction function to the hail prediction.