By using the daily reanalysis data of National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP) and daily precipitation data at 20:00 BT from Chinese meteorological stations during 1950-2015,and based on the methods of Morlet wavelet analysis and wave-packet propagation diagnosis (WPD),in this paper,we put emphasis on the research of high frequency baroclinic wave packets distribution and propagation climate characteristics of East Asian subtropical westerly jet (EASJ) in summer (June to August) and their corresponding relationships with the typical rainy season in eastern China.The results show that (1) after filtering out the monthly scale (30 days) cycle signals,highlighted 3-7 d high frequency narrowband signals of the EASJ are obvious in the 200 hPa zonal winds,covering the high frequency narrowband signals of 2 4 d and 5-7 d in South China in the rainy season,5-7 d in Jianghuai Region in Meiyu season and 2-4 d and 6-8 d in the rainstorms in the northern China from late July to August,which reflects the step changes of summer narrowband signals and the relationship with the typical rainy season in eastern China.(2) The 3-7 d high-frequency baroclinic wave packets corresponding to the East Asian subtropical westerly jet are quasi-zonal distribution,which represents the strong disturbance area,i.e.,the dynamic instability zone of the strong west wind shears.The low-value region of the wave packet corresponds to the high pressure in South Asia,which represents the weak perturbation region,i.e.,the weak wind pressure stability zone.The distribution characteristics of wave packets during the Meiyu season shows that the two 5-7 d high frequency baroclinic wave-band and high value zones in the mid latitude and high latitude have a good correspondence with the high energy values of the baroclinic energy dispersive waveguides and the critical areas influencing the precipitation of the Yangtze River and the Meiyu season.(3) The 3 7 d high-frequency baroclinic wave band,located at 40°-55°N,corresponding to the subtropical westerly jet,has the regularity of meridional displacement and intensity changes.Its meridional displacement shows that it falls on the south and rises on the north and then fluctuates,and its intensity gradually weakens and then strengthens.The latitudinal evolution of the zonal winds is divided into two stages,which are characterized by significant differences in the distribution of the wave packets.The first stage has two large wave areas,which are the Black Sea to the Caspian Sea region and the northeast of China to the island of Japan;and the second stage has three large wave areas,including the Black Sea to the Caspian Sea,the west side of the Balkhash Lake and the northeastern region of Japan,of which the disturbance of 3-7 d high frequency baroclinic wave on the west side of the Balkhash Lake has an important contribution to the precipitation in eastern China.%利用1960-2015年NCEP全球再分析日平均资料和我国2426站20时日降水量资料,采用Morlet小波分析方法和波包传播诊断分析方法,研究了夏季(6-8月)东亚副热带西风急流的窄带信号和高频斜压波波包分布特征及其与夏季我国东部典型雨季的对应关系.结果表明:(1)滤除30 d尺度以上变化后的夏季多年平均EASJ表现为显著的3～7 d高频窄带信号,该频域涵盖了华南汛期2～4和5～7 d、江淮梅雨季5～7 d以及7月下旬至8月北方暴雨的2～4和6～8 d的高频窄带信号,反映了夏季窄带信号的阶段性变化及其与我国东部典型雨季的对应关系.(2)与东亚副热带西风急流相对应的3～7 d高频斜压波波包大值带呈准纬向分布,代表强扰动区域,即急流带超地转强西风切变的动力不稳定区;波包低值区与南亚高压相对应,代表弱扰动区域,即弱风均压稳定区.进一步分析江淮梅雨季高频斜压波波包的分布特征表明,分别位于中纬度和高纬度的两条5～7 d高频斜压波波包带和高值区与影响江淮梅雨降水的斜压能量频散波导和关键区高能值有很好的对应关系.(3)与副热带西风急流相对应的位于40°～55°N的3～7 d高频斜压波波包带活动主要表现为经向位移和强度变化,其经向位移呈现先南落后北抬再波动的特征,强度表现为逐渐减弱而后加强的变化趋势.高频斜压波波包纬向分布变化以纬向风中心值位置突变为转折点分为两个阶段,表现出明显不同的波包分布特征.第一阶段有两个波包大值区,分别为黑海至里海地区和我国东北至日本岛地区;第二阶段有三个波包大值区,分别为黑海至里海地区、巴尔喀什湖西侧以及我国东北至日本岛地区,其中巴尔喀什湖西侧3～7 d高频斜压波波包扰动对我国东部降水有重要贡献.
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