夏季青藏高原湿池变化特征及其与降水的关系

Characteristics of the Moist Pool over Qinghai-Xizang Plateau and Their Association with Precipitation over China in Summer

利用1979—2011年ERA-Interim的月平均再分析资料和全国气象台站观测资料,通过小波分析、合成分析和相关分析等多种统计分析方法,分析了夏季青藏高原湿池的基本特征,定义了能较好表征夏季青藏高原湿池强度变化的特征指数,并揭示了夏季青藏高原湿池强弱异常时的大气环流特征及其与中国夏季降水的关系。主要结论为:夏季高原上湿池特征非常明显,2个湿中心分别位于高原东南部和西南部。高原湿池强度指数有明显的阶段性变化特征,以4 a左右和6 a左右的变化周期为主。夏季高原湿池偏强(弱)年,南亚高压、西太副高、高原季风、低层风场以及整层水汽输送等均有显著变化,进而对我国夏季降水产生重要影响。

Using ERA -Interim reanalysis monthly data and the monthly precipitation data atmeteorological stations in China from 1979 to 2011, we analyzed the variation characteristics of themoist pool over Qinghai-Xizang Plateau in summer. Further, we defined a moist pool index ofQinghai-Xizang Plateau and analyzed the relationship between the moist pool index and summerprecipitation in China by the wavelet transformation, correlation analysis and composite analysis.The results showed that there was a moist pool over the plateau and there was also two moisturecenters located over southeastern part, southwestern part of the Qinghai -Xizang Plateau,respectively. The summer moist pool of index showed a significant periodic variation characteristicof the Qinghai-Xizang Plateau, with quasi-periods of 4 years and 6 years. The variations of themoist pool had close connection with summer precipitation in China援The variations of the moist poolof Qinghai-Xizang Plateau intensity were closely related with persistent anomalies of atmosphericcirculation in the same period, such as the South Asia High (SAH),Western Pacific SubtropicalHigh(WPSH),Plateau summer monsoon, lower level flow field, vertically integrated water vaporflux,and then affected summer precipitation in China.