中文摘要：

利用2008年多种台站观测和再分析资料,通过相关分析和合成分析,详细讨论了青藏高原夏季风季节内变化及其与印度夏季风和东亚夏季风降水之间的关系。结果表明：2008年高原夏季风爆发偏早,降水偏多,季风活动有明显的季节内振荡特征、其准双周振荡特征与东亚夏季风指数和印度全区降水振荡周期相似。高原夏季风强（弱）时,印度全区及我国华北地区容易出现降水偏少（多）。高原夏季风偏强通常对应低层印缅槽偏东偏北,槽前水汽输送有利于高原东南部降水产生,而印度大陆受高压脊控制,为季风中断期。东亚低空西南风急流和中层西太平洋副热带高压位置偏东偏南,东亚季风降水主要发生在华东地区,南亚高压偏西偏弱;高原季风偏弱时,西太平洋副高西伸北抬,低空西南风急流偏西偏北,来自低纬的西南风水汽输送和源于西太平洋的副热带高压南侧的东南风水汽输送共同作用,有利于华北地区的降水偏多,同时南亚高压偏东偏强。高原夏季风的季节内变化与印度夏季风和东亚夏季风呈显著反相关关系,其对应的大气非绝热加热的空间分布对南亚高压东西振荡有重要作用。

英文摘要：

Using observational and reanalysis data,the variaton of the Tibetan Plateau Summer Monsoon（TPSM） and its relationship with the India Summer Monsoon（ISM） and the East Asian Summer Monsoon（EASM） are investigated by the correlation analysis and the composite analysis.Results show that the TPSM in 2008 is earlier and stronger than normal.The most significant period of the intraseasonal oscillation in the TPSM is biweekly,similar to those of all ISM rainfall and the EASM index.When the TPSM is strong（weak）,the precipitation in all India and North China tends to be less（more） than normal.During the active phase of the TPSM,the position of the Indian-Burma monsoon trough is to the east and north of its normal place,so that the moisture transportation in front of the trough is of benefit to the rainfall in the southeast of the Tibetan Plateau,but the ISM breaks for the influence of the high ridge over the Indian continent.Meanwhile,since the Western Pacific Subtropical High（WPSH） is to the east and south of its usual location,the EASM precipitation concentrates in East China.On the contrary,when the TPSM is weaker,with the WPSH expanding westward and shifting northward,the lower southwesterly jet shifts northward,thus both the southwesterly moisture transportation from lower latitudes and the southeasterly moisture transportation from the south edge of the WPSH contribute to the more precipitation in North China.It is also shown that the TPSM oscillation related to diabatic heating modulates the behavior of the South Asia high to a considerable degree.