INSPIRE: Nonequilibrium Statistical Mechanics of Natural Climate Variability: Sea-Surface Temperature and Ocean Heat Content

INSPIRE奖的部分资金来自地球科学局海洋科学部的物理海洋学计划、物理部的数学物理计划、数学科学部的计算数学计划和材料研究部的凝聚态物质和材料理论计划，所有这些都由数学和物理科学局提供。智力优势：气候系统的自然变异性主要是通过观察、气候建模和分析来了解的。自然气候变化的形式是大范围、连贯的模式，如厄尔尼诺现象和北大西洋涛动。目前还没有基本的理论来解释或预测气候系统的自然变异性。气候系统是由传入的太阳辐射产生的能量驱动的，然后以传出的长波辐射的形式释放回太空。除人为强迫外，气候系统近似处于热力学非平衡稳态。物理学界的最新进展使人们对非平衡稳态中的自然可变性有了新的、更深入的理解。非平衡稳态有能量路径，将它们的自然变异性引导到明确定义的生命周期中。这些生命周期表现为气候系统中自然变化的模式。这一INSPIRE项目将在物理学家和气候科学家之间建立一种新的跨学科合作，开发和应用非平衡涨落理论来理解和预测气候变异性。该项目利用了这两个社区之间的技术联系。线性高斯模型(LGM)是显示非平衡稳态波动的最简单模型之一。LGM已经被物理界和气候界独立地进行了广泛的研究，并展示了对一些气候现象的预测技能。LGMS允许将非平衡物理的结果立即应用于气候现象，并为非平衡物理的新发展提供了一个焦点。这个INSPIRE项目将开发一种新的方法来理解气候的自然变异性，并引入气候系统作为统计物理的一个新的应用领域。非平衡稳态的背景为理解自然变化的模式提供了一个新的理论框架。将基于模式的相空间动力学开发新的诊断方法，并将其应用于模型和数据的层次结构。对具有不同恒定二氧化碳浓度的模型和具有人为强迫的模型的研究将使我们深入了解海洋表面温度和海洋热含量的自然变异性在气候变化下将如何演变，以及这些过程在目前的气候模型中有多好的表现。非平衡物理学的新理论工作将使目前的理论朝着气候变化的方向发展。该项目有两条主线：1)将非平衡理论应用于海洋表面温度和上层海洋热含量数据集的层次结构；2)在对气候系统重要的方向上推进非平衡物理的理论工作。广泛影响：拟议的工作将作为将统计物理应用于其他自然气候变异性模式的模板。线性高斯模型的自然可变性可以为自然气候可变性的整个光谱提供零假设，即使在它失败的情况下也能提供洞察力。该项目将促进物理学和气候界的交叉发展，并为研究提供新的方向。最后，该项目将对一名研究生和一名博士后研究员进行气候建模、统计物理和气候数据分析方面的交叉培训，并将支持一名年轻教员的智力成长。

This INSPIRE award is partially funded by the Physical Oceanography Program in the Division of Ocean Sciences in the Directorate for Geosciences, and the Mathematical Physics program in the Division of Physics, the Computational Mathematics Program in the Division of Mathematical Sciences and the Condensed Matter and Materials Theory Program in the Division of Materials Research, all in the Directorate for Mathematical and Physical Sciences.Intellectual Merit: The natural variability of the climate system is primarily understood through observations, climate modeling, and analysis. Natural climate variability takes the form of large-scale, coherent patterns such as El-Nino and the North Atlantic Oscillation. There is currently no fundamental theory to explain or predict the natural variability of the climate system. The climate system is driven by energy from incoming solar radiation, which is then released back to space as outgoing long-wave radiation. The climate system, apart from anthropogenic forcing, is approximately in a thermodynamically non-equilibrium steady-state. Recent progress within the physics community has led to a new and deeper understanding of natural variability in non-equilibrium steady-states. Non-equilibrium steady-states have energetic pathways that channel their natural variability into well-define lifecycles. These lifecycles are manifested as the patterns of natural variability seen in the climate system. This INSPIRE project will create a new interdisciplinary collaboration between physicists and climate scientists developing and applying theories of non-equilibrium fluctuations to the problem of understanding and predicting climate variability. This project leverages a technical linkage between these two communities. Linear Gaussian Models (LGMs) are among the simplest models that display non-equilibrium steady-state fluctuations. LGMs have independently been extensively studied by both the physics and climate communities, and have demonstrated predictive skill for some climate phenomena. LGMs allow the immediate application of results from non-equilibrium physics to climate phenomena, and provide a focus for new developments in non-equilibrium physics.This INSPIRE project will develop a new approach to understanding the natural variability of climate and introduce the climate system as a new application area for statistical physics. The context of non-equilibrium steady-states provides a new theoretical framework for understanding the patterns of natural variability. New diagnostics, based on the phase-space dynamics of the patterns, will be developed and applied to a hierarchy of models and data. Study of models with different constant carbon dioxide concentrations, and models with anthropogenic forcing will provide insight into how the natural variability of Sea Surface Temperature and ocean heat content will evolve under climate change and how well-represented these processes are in present climate models. New theoretical work in non-equilibrium physics will extend current theory in directions motivated by climate variability. The project has two threads: 1) the application of non-equilibrium theory to a hierarchy of sea surface temperature and upper ocean heat content datasets; and 2) theoretical work to advance non-equilibrium physics in directions that are important for the climate system.Broader Impacts: The proposed work will serve as a template for application of statistical physics to other patterns of natural climate variability. The natural variability of Linear Gaussian Models can provide a null hypothesis for the entire spectrum of natural climate variability, and will provide insight even in situations where it fails. The project will serve to cross-fertilize the physics and climate communities and provide new directions for research. Finally, the project will cross-train one graduate student and one post-doctoral researcher in climate modeling, statistical physics, and climate data analysis, and will support the intellectual growth of a young faculty member.