EAGER: Climate Feedback Drift in Models and Observations

内部气候动力状态如何与气候变化相互作用的问题具有重要的理论和实践意义。这项研究探讨了令人不安的可能性，即气候系统对给定量级的辐射扰动的响应可能强烈依赖于气候状态本身。在一个海洋-大气耦合模式中，一个最先进的全物理气候模式记录了这里称为反馈漂移的基本过程。这项工作是为了利用经验研究和简化的解释性模式来理解这种反馈漂移背后的物理机制，以评估这种反馈漂移可能发生在其他完全解析的气候模式中的可能性，并发展必要的经验性理解和诊断技术，以确定这种过程是否可能在自然界中发生。如果气候反馈确实随着在基本的气候动力状态方面，我们对气候变化阈值的理解、对人为温室气体假定“安全”水平的看法以及我们对气候变异性在气候系统中的总体作用的理解必然会改变。因此，本研究在探索性的同时，也具有潜在的重要的实践意义。云/气候相互作用领域的学生。这项工作将有助于量化未来气候变化的一个潜在风险因素，这对负责实施“针对”特定气候变化水平的排放情景的决策者具有内在利益。

The question of how the internal climate dynamical state will interact with climate change is of great theoretical and practical importance. This study explores the disconcerting possibility that the response of the climate system to a radiative perturbation of a given magnitude may depend strongly upon the climate state itself. The underlying process, referred to here as feedback drift, has been documented in one coupled ocean-atmosphere model, a state-of-the-art, full physics climate model. This work is an effort to understand the physical mechanism underlying this feedback drift using both empirical studies and simplified, explanatory models, in order to assess the possibility that such feedback drift might occur in other fully resolved climate models, and to develop the necessary empirical understanding and diagnostic techniques to determine whether such a process might be occurring in nature.If indeed climate feedback drifts significantly with respect to the underlying climate dynamical state, our understanding of climate change thresholds, the perception of supposed "safe" levels of anthropogenic greenhouse gasses, and our understanding of the overall role of climate variability in the climate system will necessarily be altered. Thus, while exploratory, this research is potentially of great practical importance.This project will contribute to the training of a Ph.D. student in the area of cloud/climate interactions. The work will help quantify a potential risk factor in future climate change that is of intrinsic interest to decision makers responsible for implementing emission scenarios that "target" a given level of climate change.