Beyond the Instrumental Record: The Case of Circulation at the Last Glacial Maximum

OCE-0645936通过将广泛的仪器观测与海洋环流模式相结合，成功地估计了现代海洋环流状态。通过数值优化方法的技术进步和社区内新专业知识的发展，这种状态估计成为可能。该基础设施将被应用于确定末次冰期最大值（LGM）的环流。末次冰期对于全面了解气候变化非常重要。此外，它代表了一个与我们今天完全不同的地球，从而提供了一个在非常不同的边界条件下测试和理解海洋模型的机会。在过去20年中，已经积累了大量的LGM数据，包括营养物，瞬变和动态活跃的代理数据，并可以系统地用于进行全面的海洋状态估计，包括大气强迫。智力优点：理解当代和未来的气候变化只有在过去自然原因造成的背景下才有可能。该项目的目的是使用建模能力，物理见解和优化方法，最初开发的现代系统，以确定气候的海洋成分的LGM和大气条件，带来了它。其次，模拟LGM的能力将表明，用于研究现代和未来气候状态的模型不仅仅是为了复制现代观测而调整的，从而为他们的结果提供更大的信心。另一个副产品应该是增加对有时不透明的代理数据的具体信息内容的了解。 更广泛的影响：现代气候模型在多大程度上具有真正的技能是难以量化的，因为它们经历了几十年的发展调整和调整，这可能使它们出于错误的原因而显得现实。同一个模型能够在不同的强迫作用下定量地再现气候系统中的海洋成分，这就产生了与使用不同的类地行星来测试模型相同的信心。 该项目的成功完成将记录从现在到LGM之间海洋环流的自然变化。更一般地说，确定过去海洋变化的范围直接关系到当代气候变化中有多少是人为变化造成的，多少是自然变化。这项工作将被嵌入到一个广泛的学术计划中，旨在了解几乎所有时间和空间尺度上的气候，我们希望与学生，博士后和对过去，现在和未来气候变化的大部分方面感兴趣的同事进行互动。

OCE-0645936The modern ocean circulation state is being successfully estimated by combining a wide array of instrumental observations with an oceanic general circulation model. This state estimate is made possible through technical advances in numerical optimization methods and the development of new expertise within the community. This infrastructure will be applied toward determining the circulation of the Last Glacial Maximum (LGM). The LGM is very important for the overall understanding of climate change. In addition, it represents an earth differing radically from what we have today thus providing an opportunity to test and understand ocean models under very different boundary conditions. Considerable LGM data has been amassed over the last 20 years, to include nutrient, transient and dynamically active proxy data, and can be systematically used toward making a full oceanic state estimate, including the atmospheric forcing. Intellectual merit: Understanding contemporary and future climate change is only possible within the context of what has happened in the past from natural causes. The intention of this project is to use the modeling capabilities, physical insights, and optimization methodologies originally developed for the modern system to determine the ocean component of the climate of the LGM and the atmospheric conditions that brought it about. Secondarily, the ability to simulate the LGM would demonstrate that the models used to study modern and future climate states are not simply tuned to replicate modern observations, thus providing greater confidence in their results. Another by-product should be increased understanding of the specific information content of sometimes opaque proxy data. Broader impacts: The extent to which models of modern climate have true skill is difficult to quantify because they have undergone adjustments and tuning over many decades of development, and which may make them appear realistic for the wrong reasons. To the degree that the same model can quantitatively reproduce the ocean component of the climate system under very different forcing produces the same sort of confidence that one would gain by having a different earth-like planet to be used to test the models. The successful completion of this project will document the natural change in ocean circulation between the present and LGM. More generally, determining the range of past oceanic variability bears directly on the question of how much of contemporary climate change is forced by anthropogenic change and how much is natural. The work will be embedded in a wide-ranging academic program directed at understanding climate on nearly all time and space scales, and we expect interaction with students, post-docs and colleagues interested in most aspects of past, present, and future climate change.