两类El Niño对调控全球的短期气候异常有着重要作用。目前围绕El Niño形态变化的机理研究已经取得了诸多重要进展。然而，针对全球变暖背景下热带太平洋海温背景场对El Niño形态的影响，尚有许多科学问题值得深入探索。本项目以能表征热带太平洋海温背景场的冷舌模态为切入点，采用资料统计、动力诊断、和理论分析相结合的方法，分析热带太平洋冷舌模态对El Niño海气耦合过程的影响，进一步探讨冷舌模态影响El Niño的动力机制。在此基础上，建立用冷舌模态指数预测El Niño最终类型（东部型/中部型）的统计模型。本项目还利用CMIP5模式资料，评估模式模拟冷舌模态及其影响El Niño的能力。相关工作的开展，可为探索全球变暖强迫下的ENSO动力学提供新的思路，为两类El Niño的预测提供新的线索。

Two types of El Niño play an important role in modulating global short-term climate anomalies. Mechanisms of El Niño shape change has long been of great concern to the meteorological community. Although great progress have been made, the tropical Pacific sea surface temperature (SST) background state, as an important factor in influencing El Niño shape change, is a fundamental topic requiring further investigation. Focusing on the tropical Pacific cold tongue mode (CTM), which represents SST background state over the tropical Pacific, this project will first study influence of the CTM on El Niño’s air-sea interaction through statistical analysis. Then, potential dynamic mechanism associated with impact of the CTM on El Niño are investigated by using dynamic diagnosis and theoretical analysis methods. Based on these, this project will provide the statistical model which projects the El Niño final type (EP/CP) by using the CTM index. Using CMIP5 model datasets, this project will also evaluate model’s performance and analyze the CTM variability and its impact on El Niño in the historical simulation. The implement of these relevant work could provide more insight into understanding the ENSO dynamics under global warming and projection associated with two types of El Niño.