利用16 a的TRMM卫星观测资料,分析了亚洲季风区准圆状、线状和拉长状中尺度对流系统(MCSs)的空间分布、对流属性及其区域变化特征.结果表明:拉长状MCSs的数量最多,准圆状的其次而线状的最少.自西向东,准圆状(线状)MCSs数量占各区域MCSs总数的比例逐渐减小(增加),线状MCSs在副热带和洋面地区的产生几率相比更大.MCSs的发生频次呈现以暖季(5-9月)为峰值的单峰分布,准圆状和拉长状MCSs的暖季峰值比线状MCSs的大.MCSs主要发生在下午—傍晚时段,但线状MCSs在午夜—凌晨出现的概率比其它两种大.3种类型MCSs的整体强度基本表现为副热带地区弱于近热带地区,但不同类型MCSs的强度差异在各区域不尽相同,如中国中东部地区和西北太平洋地区的准圆状MCSs强度最强,但东海及其以东洋面的线状MCSs强度最强.%Based on the 16-year TRMM satellite data,the spatial distributions,convective properties and their regional variations of quasi-circular,line shaped,and elongated Mesoscale Convective Systems (MCSs) were investigated.Results reveal that the elongated MCSs account for a majority of total MCSs,followed by the quasi-circular and line shaped MCSs.Overall,the line shaped MCSs preferentially occur in the subtropics and over the oceans.The ratio of quasi-circular (line shaped) MCSs to the total MCSs shows a zonal decreasing (increasing) from the west to the east over the subregion.Although the MCSs predominantly occur in the warm seasons (May-September),the quasi-circular and elongated MCSs are more concentrated than the line shaped MCSs.Besides,the occurrences of MCSs are mainly concentrated in the late aftemoon,but the ratio of line shaped MCSs occurring in the midnight to dawn is higher than the other two types.From the mean states of convective proxies,MCSs in the subtropics possess weaker convective intensities than those in the tropics.However,the intensities of MCSs depend on different morphologies.For example,the quasi-circular MCSs exhibit stronger convective intensities than the line shaped and elongated MCSs over the central East China and western North Pacific,but the line shaped MCSs show stronger convective intensities than the other two types over the oceanic regions in the east of China.
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