夏季青藏高原大气热源分布特征与对中国降水的影响

利用NECP/NCAR月平均再分析资料,研究1951～2010年夏季青藏高原主体大气热源分布、对东亚地区的环流影响及其与同期中国降水的关系.针对高原加热局地特征明显的特点,采用旋转经验正交函数等方法探讨不同类型的热源分布以及对东亚地区大气环流的影响.结果表明,当加热中心位于高原东南侧时,青藏高原夏季风加强,南亚高压偏南偏东,西太平洋副热带高压西伸加强,而东亚中高纬地区两脊一槽的经向环流分布形势明显,有利于中国长江流域的降水而不利于华南华北的降水发展.当加热中心位于高原中北部与西南地区时,青藏高原夏季风减弱,南亚高压偏西,西太副高明显偏东偏弱,中高纬环流的纬向特征明显,有利于中国地区北方降水而不利于南方地区的降水.

The Characteristics of the Atmospheric Heat Source over the Tibetan Plateau and its Effect to China＇s Precipitation

By using NECP/NCAR monthly mean reanalysis data, this paper calculated the summer heat source over the Tibetan Plateau and studied its distribution, effects on the circulation in East Asia and its relationship with pre- cipitation during the same period form 1951 to 2010 in China. According to the significant local characteristics in the plateau, the paper discussed the different types of heat source distributions and its influences of the atmospheric circu- lations in East Asia by the method of rotated empirical orthogonal function（REOF）. When the heating center locates in the southeast, the summer monsoon in the Qinghai-Tibet plateau strengthened, the South Asia high expanded southward and eastward, while the western Pacific subtropical high come west and powered, the meridional circula- tion distributed with a two ridges one slot. The circulation is conducive to Yangtze River＇s precipitation and not fa- vorable to the development of rainfall in both northern and southern China. When the heating center locates in the southwest and central-northern area, the summer monsoon in the Qinghai-Tibet plateau decreased, the South Asia high stayed a main modal of Iran, the western Pacific subtropical high showed a significantly weaker and east style, corresponding to a reverse distribution in precipitation in south and north China.