南印度洋SST与南亚季风环流年代际变化的研究

RESEARCH ON INTERDECADAL VARIABILITY OF SOUTH INDIAN OCEAN SST AND SOUTH-ASIA MONSOON CIRCULATION

利用美国NCEP全球大气再分析资料和JONES全球海表面温度异常 (SSTA)资料 ,分析了南印度洋SSTA和南亚季风环流年代际变化的特征。研究发现 ,无论是南印度洋副热带海水辐合区的SST还是赤道以北非洲西海岸附近上升运动海区的SST的长期变化趋势 ,除了准 3 5年的变化以外 ,还存在着明显的年代际的变化。对于全球最显著南亚季风环流的分析表明 ,南亚季风环流也存在明显的年代际时间尺度的变化。与南太平洋SST的年代际变化相比 ,南印度洋SST的变化周期要相对短一些。通过分析南半球冷空气年代际活动的特征发现 ,冷空气与南印度洋SST年代际时间尺度的变化具有密切的联系。

The NCEP NCAR monthly mean reanalysis data and Jones&Parker's dataset which is a combination of land air temperature anomalies and sea surface temperature anomalies are used to study the interdecadal variability in South Indion Ocean SST and the South Asia monsoon circulation. It is suggested that there is interdecadal variability of long-term hange trend of SST not only in the convergence region over the subtropic of the south Indian Ocean but also in the upwelling region near Africa north of the equatior. The study of the South Asia monsoon circulation clearly shows that there is interdecadal variation it. The interdecadal variability of SST has shorter periods over the South Indian Ocean than over the South Pacific Ocean. And a close relationship was found between the cold air activity and the change of interdecadal timescale of South Indian Ocean SST by studying the interdecadal variation of the cold air activity over the Southern Hemisphere.