采用1948-2010年NCEP/NCAR再分析潜热通量资料,利用经验正交分解(EOF)方法,分析了夏季热带太平洋潜热通量变化的时空特征,并探讨了中国东部夏季降水异常与潜热通量变化时空格局的关系.结果显示,热带东太平洋潜热通量变化存在明显的线性减小趋势；潜热通量还具有在年际时间尺度上的变化特征.热带太平洋潜热通量第一模态时间系数与中国夏季降水相关系数表现为“南正北负”型分布,表明热带太平洋地区的潜热通量减少可能是造成我国夏季降水在20世纪70年代以后长江中下游及华南地区夏季降水明显偏多,东北、华北地区夏季降水明显偏少的影响因素之一.进一步分析表明,热带东太平洋潜热通量异常偏少时,造成东亚地区500hPa位势高度场异常偏高,形成向南的水汽输送异常,并可能通过东亚副热带西风急流年际变化影响中国夏季降水分布.%Using the NCEP/NCAR reanalysis latent heat flux data from 1948 to 2010, the spatial-temporal char-acteristics of decadal variations of equatorial Pacific are analyzed by the EOF method and the relation between the latent heat flux and the anomalous summer rainfall in China is revealed. The results show that there is a steady decrease of latent heat flux and also inter-annual variability of latent heat flux in the eastern equatorial Pa-cific. The correlation coefficient of the first principal component of EOF analysis and the summer rainfall in Chi-na is obviously positive along the Yangtze River while negative in the northern China. The latent heat flux in the equatorial Pacific is an important factor that influences the rainfall pattern in China after the 1970's. The anoma-lously negative latent heat flux in the Eastern equatorial Pacific might induce the anomalously positive 500hPa geopotential height in the East Asia and the anomalous southward atmospheric water vapor transport. The in-ter-annual variability of the East Asian Subtropical Westerly Jet Stream might influence the inter-annual variations of summer rainfall in China.
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