Collaborative Research: A Global Bridge From Eddy-Rich to Eddy-Less: Quantifying, Mapping, and Improving Treatment of Mesoscale Eddy Tracer Fluxes

以前的模型需要“英雄计算”来模拟10年的模型时间，现在类似的模型可以运行几个世纪。然而，中尺度涡旋参数化仍然是需要的：不断增加的系统复杂性、模拟长度、集合大小以及在台式计算机上运行的海洋模型需要在未来几十年里持续使用粗糙模型。理想情况下，涡流参数化应该直接根据观测结果进行验证，但所需观测的密度使这种选择不切实际。针对更高分辨率计算的测试是一种有效的替代方法，但这些比较很少或不完全完成。这个项目将以直接和彻底的方式在全球范围内提供这样的比较。将出现三个产品：1)在精细分辨率模拟中对完整涡流搅拌张量的全局诊断，2)与使用现有参数化预测的搅拌张量的比较，以及3)a ？参数化挑战套件？基于精细分辨率模型中的旋转区域。大多数现存的涡流参数化可以完全用涡流搅拌张量来表示。这个张量的诊断代表了一个重大的进步，目前最先进的研究只诊断标量涡扩散率或其他有限的张量结构。与全张量的全局一致性是一个严格的测试，它将导致立即改进或全盘拒绝参数化。除了用于比较的数据集之外，拥有用于参数化开发的测试用例也很有用。传统上，涡流参数化已经在容易产生伪影的理想设置中进行了测试。本研究的第三个产品将是一套由全球高分辨率模拟原型构建的大约6个挑战。挑战将提供足够的信息，以作为独立的前向模型运行。将设计全套挑战，以便在所有挑战中成功地参数化，从而预测在全局模型中可能取得的成功。在粗略的海洋模型中，在参数化中尺度涡旋方面已经取得了很大的进展，但下一个精度水平需要在涡旋丰富的数据集和测试套件中更好地定义度量，现有的和即将到来的参数化可以根据这些指标进行验证。这项研究将提供直接的产品，可以使用适度的计算机资源，并且在现实循环中诊断的全局性将防止常见的伪影。该项目将增加对全球尺度中尺度涡旋动力学和涡旋参数化假设的理解，改进或拒绝现有的涡旋参数化方案，并测试一种新的诊断方法。该项目将支持两名早期职业研究人员和一名研究生，公开提供可管理的大型模拟版本，改进海洋和气候模型，改进POP模型的性能，并支持和鼓励研究机构和建模者与更大的社区之间的合作。

The previous models required a "hero calculation" to simulate a decade of model time, now similar models run for centuries. However, mesoscale eddy parameterizations are still needed: increasing system complexity, simulation length, ensemble size, and running ocean models on desktop computers require a continuous use of coarse models for decades to come. Ideally, eddy parameterizations should be validated directly against observations, but the density of observations required renders this option impracticable. Tests against higher resolution calculations are an effective alternative, but these comparisons are rarely or incompletely done. This project will provide such a comparison globally in a direct and thorough manner. Three products will emerge: 1) a global diagnosis of the complete eddy stirring tensor in a fine-resolution simulation, 2) a comparison to the stirring tensor predicted using extant parameterizations, and 3) a ?parameterization challenge suite? based on eddying regions in the fine-resolution model. Most extant eddy parameterizations may be written completely in terms of the eddy stirring tensor. Diagnosis of this tensor represents a significant advance over presently state-of-the-art studies diagnosing only a scalar eddy diffusivity or otherwise limited tensor structure. Agreement with the full tensor globally is a stringent test that will lead to immediate improvement or wholesale rejection of parameterizations. In addition to a dataset for comparison, it is useful to have test cases for parameterization development. Traditionally, eddy parameterizations have been tested in artifact-prone idealized settings. The third product of this study will be a suite of perhaps 6 challenges constructed from prototypes in the global high-resolution simulation. A challenge will provide enough information to be run as a stand-alone forward model. The full suite of challenges will be designed so that a successful parameterization in all challenges will predict likely success in a global model. Much progress has been made in parameterizing mesoscale eddies in coarse ocean models, but the next level of accuracy requires better defined metrics in eddy-rich datasets and test suites against which extant and forthcoming parameterizations can be validated. This study will provide direct products accessible with moderate computer resources, and the global nature of the diagnosis in a realistic circulation will prevent common artifacts. The project will increase understanding of mesoscale eddy dynamics on a global scale and the assumptions underlying eddy parameterizations, improve or reject extant eddy parameterization schemes, and test a novel diagnostic methodology. The project will support two early-career researchers and a graduate student, publicly provide manageably-sized versions of a huge simulation, lead to improvements in ocean and climate models, lead to performance improvement of the POP model, and support and encourage collaboration among research institutions and modelers with the larger community.