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从计算大尺度热源和分析ＴＢＢ资料两个方面，阐述了１９９１年江淮梅雨期间降水性质与对流活动的季节性演变特征。结果表明：梅雨期间江淮上空３个强上升运动时段分别形成了３场暴雨，由暴雨释放的热量使江淮大气出现了３个时段的强加热；３场暴雨的降水性质呈显著的季节性演变，由第１场暴雨以锋面性降水为主发展到第３场暴雨异常强的对流性降水。文中详细分析了热源和水汽汇的时空分布特征，并从大气运动场和热力结构讨论了盛夏强对流降水期间积云对流以涡动形式对热量和水汽的强铅直输送作用。江淮地区ＴＢＢ值能很好地反映降水状况，雨期一致地对应于ＴＢＢ低于２５０Ｋ的时段。梅雨中后期东亚地区对流活动季节性地增强，带状对流区（特别是ＴＢＢ高负距平区）与雨带位置相符。对流带位置及对流活动强弱与西南暖湿气流活动密切相关，它很好地表征了东亚地区的低空急流（给积云输送热带对流大气）。梅雨期间对流带主要出现在江淮流域，但可在东亚范围内飘移，它落在江淮与否则决定了江淮暴雨的维持与中断
From two aspects of calculating large-scale heat source and analyzing TBB data, the seasonal evolution characteristics of precipitation and convection during the plum rains in 1991 are expounded. The results show that during the rainy season, three strong updrafts formed over the Jianghuai period, respectively, and three heavy rainfalls formed during the rainy season. The heat released by the rainstorm caused strong heating in the Jianghuai atmosphere over three periods. The precipitation characteristics of the three heavy rainstorms showed significant seasonal evolution, From the first rainstorm to the frontal precipitation developed to the third rainstorm exceptionally strong convective precipitation. In this paper, the temporal and spatial distribution characteristics of heat source and water vapor are analyzed in detail. The strong vertical heat and moisture transport of cumulus convection in the form of vortex during midsummer convective precipitation is discussed from the field of atmospheric motion and the thermal structure. The TBB value in the Jianghuai area can reflect the precipitation well, and the rain period corresponds to the period when the TBB is less than 250K. The convective activities in East Asia during the latter part of the Meiyu Period are increasing seasonally, and the convection zone (especially the TBB high negative anomaly area) coincides with the rain belt location. The position of convective belt and the intensity of convective activity are closely related to the activity of warm and humid southwestern China. It is a good indicator of the low-level jet stream in East Asia (the convective cumulus convects the tropical convective atmosphere). Convection belt during the rainy season mainly occurs in the Yangtze River and Huaihe River basin, but it can drift within the range of East Asia. It falls on the Jianghuai River and otherwise determines the maintenance and interruption of the Jianghuai rainstorm