中文摘要：

使用ECMWF再分析数据集资料中的位势高度场、三维风场、温度场、相对湿度场、海温场以及中国气象局730站地面降水资料和日最高温度资料,对比分析研究了7月份西太平洋副高位置偏南和偏北过程（持续满足南、北位置指标6天以上定义为一次南、北部型过程）所对应的动态气候特征及其演变。分析首先揭示出了西太平洋副高的南北位置变化存在季节内振荡特征;从西太平洋副高偏南、偏北位置所对应的各层环流特征、中国东部降水分布、中国日最高温度的分布,研究了西太平洋副高南北位置对东亚及西北太平洋地区天气气候的影响。结果表明,尽管同在7月份,西太平洋副高南北位置的不同对大气环流和天气气候的影响却有显著的差异,需要从大气系统变化的角度研究和认识某时期的天气气候特征。针对两类过程的演变,分析了西太平洋副高南、北位相过程开始的前兆气候特征,过程中的变化特征以及过程结束后的后延影响,揭示出了一些以前研究所忽略的气候演变特征及其差异。

英文摘要：

The geopotential height,wind field（u,v,w）,temperature,relative humidity,maximum temperature,and SST fields in the ECMWF reanalysis data sets and the observational precipitation data in China are used to study the dynamic climate features and the evolution of subtropical high over the northwestern Pacific in July.Two processes which describe the south and north positions of subtropical high are defined（south or north position lasting for more than six days is defined as one process）and the correspondence composite analysis are completed.The results show that the intraseasonal oscillation is obvious both in the south and north processes,and the most typical oscillation occurs in July.Corresponding to the south and north processes of the subtropical high,there are evident different features and evolutions in atmospheric circulation,the distribution of precipitation,the maximum temperature in China,and the SST anomaly in the northwestern Pacific.This means that it is necessary to study and understand the dynamic characteristic of weather and climate based on the variability of the atmospheric system even though just in July as a short period.Through the analysis of process evolutions,some interesting results on the premonition characteristic,variation features during and after the north,south processes of subtropical high are indicated,which are undiscovered in previous studies.