西中太平洋经向大气环流的年际变化

Interannual Variability of the Western and Central Pacific Meridional Atmospheric Circulation

讨论了西中太平洋经向大气环流的年际变化特征,其中西太平洋区(WP)和中太平洋区(CP)EOF分解的第一模态分别是WP的负异常Hadley环流和CP的正异常Hadley环流,其时间系数与Nio3.4指数极为一致;第二模态的最显著空间特征是两区都在5°N^15°N有异常上升,但其时间系数与Nio3.4指数同期相关很低。西中太平洋有2类海表面温度异常(SSTa),通过其上的深对流潜热加热驱动异常Hadley环流:El Nio型驱动了WP区和CP区赤道区符号相反的第一模态异常环流型;热带辐合带(ITCZ)型驱动了WP区和CP区5°N^15°N区符号一致的第二模态异常环流。

The interannual variability of the western and central Pacific Meridional circulation is discussed in this paper. For the first EOF mode （model）, a negative Hadley circulation anomaly is found in the western Pacific （WP）, while a positive Hadley circulation anomaly is found in the central Pacific （CP）. Time series of model closely correlated with Nifio3.4 index. For the second mode （mode2）, the most significant characteristic is the abnormal rising zone between 5°N and 15°N in both WP and CP areas, mode2 has low contemporaneous correlation with Nino3.4 index. In the western and central Pacific, the anomaly Hadley circulations are droved by the deep convective latent heating, and they are related two kinds of sea surface temperature anomalies （SSTa） distributions： El Nifio-type, which drives opposite sign anomalies in the WP and CP equatorial area as model; and intertropical convergence zone （ITCZ） type, which drives symbols consistent anomalies between 5°N and 15°N in the WP and CP area as mode2.