印度洋偶极子与中国东部夏季降水的年代际变化关系

Decadal Variability of the Indian Ocean Dipole Interannual Relationships with Summer Rainfall in Eastern China

采用1951—2012年GPCP、中国160站台站降水资料及NOAA海表温度资料,分析了中国东部夏季降水及热带印度洋偶极子(IOD)的年际变化特征,以及两者的年代际变化关系。结果表明,中国东部夏季降水主要呈现两种模态分布,即"+-+"三极型和"-+"偶极型。并且在1953—1973年和2002—2012年中国东部夏季降水分别存在准2 a和4 a的震荡周期,年际变化明显。相关性分析发现,夏季IOD时间序列与中国东部夏季降水场的第三模态所对应的时间序列场呈负相关关系,且通过了信度为0.05的显著性检验,说明夏季IOD与中国东部夏季降水第三模态相关性较好。

The GPCP （Global Precipitation Climatology Project） data, 160 sites station rainfall data in China and NOAA sea surface temperature data from 1951 to 2012 are used to discuss the interannual variability of summer precipitation in eastern China and the tropical Indian Ocean dipole, and their interannual variation relationships are also analyzed. The results show that summer rainfall precipitation in eastern China is mainly characterized by two modal distributions： “＋ - ＋” three pole and “- ＋” dipole. The precipitation in eastern China presents a two year oscillation during the 1953-1973 and a four year oscillation during 2002-2012. The correlation analysis shows that there is a negative correlation between the time series of summer IOD and the third mode of summer precipitation in eastern China, and pass the signicant test at 005 level, which means that the summer IOD is well correlated with the third mode of summer precipitation in eastern China.