Physical Relations Governing the Response of the Global Sea Ice Cover to Climate Change

施耐德1107795加州理工学院PIS将使用系统的方法来阐明在季节性和更长时间尺度上控制海冰厚度和面积范围的过程。首先，他们将确定当前综合全球气候模型(GCM)中稳健的反应。接下来，他们将发展解释这些反应的基本理论，从考虑物理第一原理开始，通过不断增加复杂性的模型层次进行模拟，最后通过卫星观测对理论进行测试。一个主要的工具将是一个理想化的大气--海冰GCM，它有助于弥合对基本过程的理解和利用全面的GCM进行模拟之间的差距。使用这个和其他模型，他们将在海冰变化的更广泛背景下测试为北极海冰消退而开发的理论，从完全有冰的星球到完全没有冰的星球，气候的连续体都是如此。这些理论将被用来解释观测到的海冰变化，并评估当前GCM预测的不同方面，如21世纪北冰洋海冰的消退速度。需要解决的具体问题包括：？海冰和气候系统的其他组成部分之间的相互作用如何决定半球海冰覆盖的季节周期？什么物理原理决定了海冰对气候变化的敏感性？这项拟议的研究将阐明一些关于海冰动力学和气候的最基本问题。它将弥合最先进的GCM模拟和基本物理理解之间的差距，从而为模型评估提供衡量标准，提出改进模型的方法，并减少预测未来海冰消退的不确定性。通过探索广泛气候中的海冰消退，它将把过去和未来可能发生的北极海冰变化放在更广泛的背景下。

Schneider 1107795California Institute of TechnologyThe PIs will use a systematic approach to elucidate the processes that control sea ice thickness and areal extent on seasonal and longer timescales. First, they will identify responses that are robust among current comprehensive global climate models (GCMs). Next, they will develop fundamental theories to explain these responses, beginning with the consideration of physical first principles, continuing through simulations with a hierarchy of models with increasing levels of complexity, and culminating in tests of the theories with satellite-derived observations. A principal tool will be an idealized atmosphere?sea ice GCM, which helps bridge the gap between understanding of fundamental processes and simulations with comprehensive GCMs. Using this and other models, they will test the theories developed for Arctic sea ice retreat in the broader context of sea ice changes in a continuum of climates spanning the full range from a completely ice-covered to a completely ice-free planet. These theories will be used to interpret observed sea ice changes and to evaluate the aspects of current GCM projections that differ among the models, such as the rate of 21st-century Arctic sea ice retreat. Specific questions to be addressed include:? How do interactions between sea ice and other components of the climate system determine the seasonal cycle of hemispheric sea ice cover?? What physical principles govern the sensitivity of sea ice to climate changes?The proposed research will elucidate some of the most fundamental questions about the dynamics of sea ice and climate. It will bridge the gap between state-of-the-art GCM simulations and fundamental physical understanding, thereby providing metrics for model assessment, suggesting ways for model improvement, and reducing the uncertainty in the prediction of future sea ice retreat. By exploring sea ice retreat in a wide range of climates, it will place past and possible future Arctic sea ice changes in a broader context.