聖嬰與南方振盪為全球熱帶年際變化裡最顯著的氣候現象。聖嬰的發展不僅牽動了赤道上諸多的海氣耦合機制，它與多重尺度氣候因子的交互作用，也為全球的氣候與天氣現象帶來深遠廣博的影響。在聖嬰自發展、成熟、衰退至轉型的演化過程中，赤道洋流系統扮演著十分關鍵的角色。在Jin 1997提出的聖嬰-反聖嬰循環振盪的Recharge Oscillator機制中，海洋的垂直湧升流主控著聖嬰的成長率，而聖嬰轉型為反聖嬰的強度與相位則由海洋的東西向平流與垂直湧升流所共同影響。有趣的是，赤道洋流系統也反過來受到聖嬰分歧性演化機制的影響，在聖嬰的不同面貌下，赤道洋流系統也有著相應截然不同的變化。換句話說，聖嬰和赤道洋流系統之間存在著相互回饋影響的緊密關係。本研究將透過觀測資料與CMIP5/6海氣耦合模式的診斷，驗證聖嬰分歧性動力機制與赤道洋流系統之間”被影響與回饋”的雙向關係。進一步，本研究計劃建立一個結合赤道洋流系統的聖嬰理論模型，除了提高對聖嬰複雜性的模擬能力，也冀望能用此模式在未來解決更多與聖嬰相關的重要氣候問題。 ;El Niño-Southern Oscillation (ENSO) is the most substantial interannual variability in our climate system. It is strongly involved in many atmosphere-ocean coupled dynamics in the equatorial area. Moreover, the interactions between ENSO and other climatic phenomena also bring serious impacts to global climate and weather system through a direct or indirect way. Therefore, understanding and well predicting ENSO dynamics is very crucial in climatic research. The equatorial circulation system is found to play a key role in the evolution of ENSO. In the ENSO Recharge Oscillator (Jin, 1997), the phase transition of ENSO is jointly controlled by the zonal advection driven by the equatorial zonal currents and the thermocline feedback driven by the equatorial mean upwelling. The thermocline feedback resulted from equatorial mean upwelling also serves as the main contributor to the growth rate of ENSO. Conversely, the equatorial circulation system is also tightly impacted by the dynamics of ENSO diversity. According to previous studies, the equatorial circulations tend to have very different features under different flavors of ENSO evolutions. In brief, there is two-way relationship between the ENSO diversity evolution and the equatorial circulation system. This study is aimed at exploring this so called “impacted and feedback” relationship between ENSO and equatorial circulation system, through building a theory in observations and diagnosing in CMIP5/6 coupled models. Based on these analyses, we would like to develop a theoretical model of ENSO concerning the feedbacks of equatorial circulations and upwelling system. Hopefully this theoretical model will make a significant progress in characterizing ENSO features and solving more substantial climatic problems.
