华东中部地区弓状回波统计特征分析OA

Bow echoes are Mesoscale Convective Systems(MCSs)characterized by bow-shaped radar reflectivity patterns.Classic Bow Echoes(CBEs)typically develop from squall lines or convective cells,whereas Merger-formation Bow Echoes(MFBEs)arise from the merging of linear systems with pre-line convection.The latter often exhibit more severe weather hazards.This study systematically categorizes bow echoes in central East China during 2019-2022 using multi-source datasets,including radar mosaic composites,ERA5 reanalysis data,sounding observations,and surface observations.Statistical analyses are conducted to investigate the spatiotemporal distributions,environmental configurations,and surface precipitation characteristics.Results reveal 19 bow echo events in Central East China during the study period,with MFBEs accounting for 74%(14 cases)and CBEs 26%(5 cases).MFBEs exhibit a dual-peak diurnal pattern in maturation time(primary afternoon peak and secondary nocturnal peak),whereas CBEs show a single afternoon peak.Comparative analysis of environmental conditions demonstrates that MFBEs are associated with stronger warm and moist airflows,highlighting thermodynamic instability as the dominant mechanism for convective development.Additionally,MFBEs exhibit higher SWEAT index values and lower LIFT index values.In contrast,CBEs are dynamically driven,characterized by enhanced low-level convergence and vertical wind shear.Precipitation analysis indicates that MFBEs produce more spatially extensive heavy rainfall cores.This study systematically uncovers the classification and statistical attributes of bow echoes in Central East China,emphasizing the high frequency and enhanced destructive capacity of MFBEs.