全球大气／热带太平洋耦合距平模式中由ENSO增暖引起的全球大气环流异常

本文利用全球大气／热带太平洋耦合距平模式模拟了一次类似于实际的ENSO增暖过程，并对由ENSO增暖引起的海洋和全球大气环流异常的主要特征进行了分析，指出:耦合模式中的ENSO增暖在热带地区主要伴随着赤道中西太平洋Walker环流的减弱、中东太平洋气压降低以及表层辐合上升运动的增强；夏季和冬季低纬环流异常具有明显的差异性，夏季主要表现为印度夏季风环流的显著减弱和东亚季风的增强，而冬季则主要表现为赤道所有纬向环流圈均减弱；温带大气环流异常冬夏季也具有明显不同特征，夏季温带大气异常主要限于东半球，且发源于亚洲季风区，和赤道中东太平洋海温异常似无直接联系，但冬季温带大气异常则主要是发源于海温异常区的波列响应，反映了海温异常直接热力强迫的结果。另外，本文对耦合模式中的温带大气环流异常产生的可能机制也进行了讨论。

Global Atmospheric Anomalies during Warm ENSO Period in a Coupled Atmosphere-Ocean Anomaly Model

By using a multi-level anomaly GCM coupled to a tropical Pacific anomaly model, a warm, developing ENSO phase has been preliminarily simulated. The characteristic of both the ocean anomaly and the global atmospheric anomaly in each season during the warm period has also been depicted. It is pointed out that the warm ENSO period is generally accompanied by the anomalously weak Walker cell in the central-western equatorial Pacific. However, the atmospheric anomalies at lower latitudes exhibit notable seasonal difference. In summer, it is characterized by the anomalously weak Indian monsoon and strong East Asian monsoon, while, in winter,it is by the weakening of all the equatorial circulation cells. Atmospheric anomalies in the extratropics in summer are also different from those in winter. In summer, they originate in Asian monsoon areas and seem to be indirectly connected with the equatorial SST anomaly, while,in winter,they reflect direct wavetrain response to the SST anomaly.Finally, the dynamical mechanism explaining the atmospheric anomalies appearing in the coupled atmosphere-ocean system is also discussed.