夏季南亚高压移上高原时间特征的初步分析

本文利用合成分析等方法分析了南亚高压上高原早晚东亚地区大气环流特征,并讨论了其对我国东部地区降水的影响。结果表明,南亚高压上高原时间变化不仅存在8 a的长周期变化,还存在2 a的短周期变化。在南亚高压上高原偏早(晚)年,南亚高压强度较平均态强(弱),东伸指数较平均值大(小)。并且偏晚年,850hPa上西太平洋副高较平均态偏西,长江流域地区存在辐合,降水增加;偏早年则反之。

Characteristics of the South Asia High Moving on Tibetan Plateau during Summer

By using the composite analysis, The time of South Asia high (SAH) moving on Tibetan Plateau (TP) and its feature of general circulation in East Asia and the influence on the precipitation in eastern China are analyzed.Results show that the variation of the time of SAH moving on TP has not only the 8a period but also the 2a period.In the earlier (later) year of SAH moving on PT, the SAH becomes stronger (weaker) than the average state, and is more by east (west).And in the later years of SAH moving on PT, 850hPa anomalies wind indicates that the Western Pacific subtropical high is more by west in compare with average, the Yangtze River valley have convergence which result in much more precipitation;and it is just the reverse in the earlier years.