Collaborative Research: P2C2--The Role of El Niño/Southern Oscillation (ENSO) Nonlinearities and Asymmetries in Modulating Tropical Pacific Climate

该合作项目的总体目标是开发一种多尺度模式-代理综合方法，以探索过去气候中ENSO多年代际变率与热带太平洋表面温度（SST）梯度之间的关系，并帮助评估模式在过去、现在和潜在未来气候中模拟这些关系的技能。El Niño/南方涛动（ENSO）的活动在几十年至百年的时间尺度上变化显著，即使在没有外部强迫的情况下也是如此。ENSO活动增加的时期可能会影响热带太平洋的平均状态，这是由于大型El Niño事件的残余加热导致纬向海温梯度的减少。反过来，enso调制的纬向海温梯度的多年代际变化可以对全球温度趋势产生影响。目前，这些因果关系被认为在模型和观察中没有得到很好的约束。该项目的优点是很高的，因为它确定了一个有趣的科学问题（即，ENSO-平均状态相互作用），这对于推进我们对ENSO动力学和年代际气候变率的理解很重要，可以从使用古气候代理中获益。预期的结果有可能有助于解释在当前气候中观测到的年代际变率，并有助于选择有可能对未来气候作出更准确预估的气候模式。更广泛的影响包括有可能提高对未来热带气候的理论和模式的信心；帮助培养新一代的地球科学家，他们愿意弥合建模和古气候数据之间的鸿沟；支持两名早期职业女性科学家；并资助两名博士生。

This collaborative project generally aims to develop a multi-scale model-proxy synthesis to explore the relationship between multi-decadal ENSO variability and tropical Pacific seas surface temperature (SST) gradients in past climates and help assess model skill in simulating these relationships in past, present, and potential future climates.The activity of El Niño/Southern Oscillation (ENSO) varies significantly at multi-decadal to centennial timescales, even in the absence of external forcing. Periods of increased ENSO activity may affect the mean state of the tropical Pacific, via a decrease of the zonal SST gradient due to residual heating from large El Niño events. In turn, ENSO-modulated multi-decadal variations of the zonal SST gradient can exert influence on global temperature trends. These causal links are argued to be poorly constrained in models and observations, at present.The merit of the project is high because it identifies an interesting scientific issue (i.e., the ENSO-mean state interaction) that is important for advancing our understanding the dynamics of ENSO and decadal climate variability that can benefit from using paleo-climate proxies. The anticipated results have the potential to aid in interpreting the decadal variability observed in the present-day climate and the selection of climate models that have the potential to make more accurate projections of future climate.The Broader Impacts involve the potential for creating increased confidence in theory and models of future climate in the tropics; helping create a new generation of earth scientists willing to bridge the divide between the worlds of modeling and paleoclimate data; support two early career female scientists; and support two doctoral students.