利用GMS-5、FY-2B和FY-2C等3颗静止气象卫星的资料, 对2001年-2009年夏季发生在江淮区域内的35次暴雨过程和43次冰雹过程进行分析, 研究暴雨、冰雹这两种强对流天气过程中对流云合并现象的特征。统计结果显示, 只有65%冰雹过程中出现对流云合并, 平均每个过程出现1.9次合并;而暴雨过程中, 不仅有94%出现了合并, 而且平均每个过程发生合并的频次也高达11.6次。从对流云之间的距离Dis、面积比Ar、云顶亮温最低值T_min、最低亮温差异dT_min以及最低亮温变化幅度ΔT_min这5个量的统计与对比发现, 两种强天气中的合并现象既有相同规律, 也有不同的特征。通过进一步分析数值差异, 得到不同云顶亮温最低值T_min和最低亮温差异dT_min组合下, 两强天气过程中不同面积比合并过程发生的可能性。结合距离Dis、面积比Ar得到了区分对流云合并后是产生冰雹还是引起暴雨的线索。

Three kinds of satellite infrared imagery from 2001 to 2009, namely, GMS-5, FY-2B, and FY-2C, were used to study the characteristics of convective cloud mergers in summer severe weather in the Huaihe and Yangtze River basin. In the 35 heavy rain and 43 hailstorm cases, the occurrence probabilities of cloud merger were 94% and 65%, respectively. The average cloud merging times were 11.6 and 1.9. In addition, five statistic factors, namely, distance of two clouds (Dis), ratio of two cloud areas (Ar), minimum of two cloud top bright temperature clouds (T_min), difference of two cloud top lowest bright temperature (dT_min), and change of T_min (ΔT_min), were calculated and compared in the cases of hailstorm and heavy rain. Three similar points were found for the two kinds of severe weather. The quantities of the four factors comprised the main differences of the merging process in the two kinds of severe weather. Based on the combination of T_min and dT_min, the cloud top temperature conditions and the statistic probabilities of occurrence with different Ar were analyzed. Finally, three indicators for severe weather forecasting were revealed with Dis and Ar factors.