Collaborative Research: Balanced Models--Theoretical Development, Solution and Application

协作研究：平衡模型——理论发展、解决方案与应用

• 批准号: 0833032
• 负责人: Wayne Schubert
• 金额: $ 28万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-11-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0833032&HistoricalAwards=false
• 关键词: Collaborative; Research; Balanced; Models; Theoretical

Balanced atmospheric models are systems of equations based on an assumption of approximate balance between the wind and mass fields. Existing balanced models have played a key role in advancing our understanding of atmospheric dynamics. Their usefulness, however, is limited by the accuracy of the underlying balance assumption, and none is capable of representing asymmetric flows with large curvature, such as are encountered in hurricanes. The goal of this project is to remedy this situation, by extending the theory of balanced atmospheric models, developing efficient and robust methods for their numerical solution, and using the resulting models to study aspects of hurricane dynamics and midlatitude weather phenomena.The principal theoretical task is to develop two new balanced models in continuous form: a three-dimensional f-plane model for limited-area midlatitude dynamics and tropical cyclones and its generalization to spherical coordinates for global flows. Both will be based on the nonlinear balance assumption. The resulting models will be applied to explore basic dynamical principles, including available potential energy and angular momentum principles, and necessary conditions for combined instability, and wave-mean flow interactions; to study aspects of hurricane dynamics, including potential vorticity rings, secondary eyewalls, the role of asymmetries in the evolution of the mean vortex, responses to lower- and upper-level potential vorticity anomalies, and the role of small-scale fluctuations of temperature and moisture not controlled by the invertibility principle; to investigate weather-scale phenomena, including effects of horizontal shears on frontogenesis in three dimensions; and to high Rossby number turbulence, focusing on the extent to which features of quasi-geostrophic turbulence carry over to the new spherical model.Broader impacts of the project are in developing user-friendly software for the new balanced models, which will be made available to other researchers to facilitate additional studies of atmospheric dynamics. The graduate students involved in this work will receive training which will prepare them for careers in research. Increased knowledge of hurricane dynamics may someday contribute to an improved ability to predict hurricane intensity changes. Finally, this collaborative project will foster increased interaction between the computational mathematics and atmospheric dynamics communities.

平衡大气模型是基于风和质量场之间近似平衡的方程式系统。现有的平衡模型在促进我们对大气动态的理解方面发挥了关键作用。然而，它们的实用性受到基础平衡假设的准确性的限制，并且没有一个能够代表具有较大曲率的不对称流动，例如在飓风中遇到的不对称流动。该项目的目的是通过扩展均衡大气模型的理论，为其数值解决方案开发高效且健壮的方法，并使用结果模型来研究飓风动力学和中纬度天气现象的各个方面，主要理论任务是连续发展的两个新的平衡模型：三维式式模型：用于全球流的球形坐标。两者都将基于非线性平衡假设。所得模型将应用于探索基本的动力学原理，包括可用的势能和角动量原理，以及合并不稳定性的必要条件以及波平均流动相互作用；研究飓风动力学的各个方面，包括潜在的涡度环，次要眼墙，不对称性在平均涡流演变中的作用，对下层和上层潜在涡度异常的反应以及温度和水分的小规模波动的作用，无法由倒置原理控制；研究天气规模的现象，包括水平剪切对三个维度的额叶发生的影响；对于高度rossby数字的湍流，重点介绍了准地球湍流的特征在多大程度上延续到了新的球形模型中。该项目的影响力的影响是为新的平衡模型开发对用户友好的软件，这些软件将为其他研究人员提供，以促进大气动力学的其他研究。参与这项工作的研究生将接受培训，这将为研究工作做好准备。对飓风动态的知识增加可能有一天有助于提高预测飓风强度变化的能力。最后，这个协作项目将促进计算数学和大气动态社区之间的互动。