Understanding the Development and Application of Simplified Dynamical Models

了解简化动力学模型的发展和应用

• 批准号: 0837932
• 负责人: Wayne Schubert
• 金额: $ 52.88万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-11-01 至 2013-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0837932&HistoricalAwards=false
• 关键词: Understanding; Development; Application; Simplified; Dynamical

The goal of this research is to provide improved understanding of the dynamics of the tropical atmosphere through the development and application of filtered models. Filtered models are simplified dynamical models that describe low-frequency atmospheric motions but do not allow freely propagating inertia-gravity waves. This project builds on the Principal Investigator's (PI's) research expertise in tropical dynamics and advances his previous work. The project has two main parts, both of which involve the application of filtered models to the tropical atmosphere. Part I focuses on large-scale tropical dynamics and involves the theoretical development of the new and improved filtered models to be used. Part II utilizes theory based on an existing filtered model and focuses on hurricane dynamics. The longwave model is an existing filtered model designed for large-scale tropical applications and has been an important tool in tropical research. It accurately describes Kelvin waves and long Rossby waves, but has the deficiency that it badly distorts short Rossby waves. In part I of this project, the PI will improve the longwave model and thereby provide the tropical research community with an important new tool for understanding large-scale tropical motions. In addition, he will generalize this new filtered model, developed in the framework of equatorial beta-plane theory, to the sphere. This will provide, for the first time, a filtered dynamical model that accurately describes both the global PV dynamics of Rossby-Haurwitz waves and the non-PV dynamics of Kelvin waves. Among the many possible generalizations and applications of these new filtered models, the following will be studied in detail: (a) improved simulations of the MJO; (b) generation of accurate analytical solutions to Laplace's tidal equations; (c) derivation and solution of a "tropical omega-equation" to understand vertical motion fields associated with the Hadley and Walker circulations; (d) derivation and application of a ray tracing theory on the sphere for both inertia-gravity waves and Rossby-Haurwitz waves, with the goal of improved understanding of midlatitude-tropical interactions; (e) development of new spheroidal harmonic (as opposed to spherical harmonic) analysis tools for geophysical turbulence, with the goal of extending the concept of the Rhines' barrier from two-dimensional wavenumber space to three-dimensional wavenumber space.Part II of this project will utilize the Eliassen balanced vortex model, a filtered model designed for tropical cyclone applications, to help us better understand hurricane dynamics, especially the process of rapid intensification. Here the PI will use the geopotential tendency equation, derived from the original momentum, continuity, and thermodynamic equations, to isolate the conditions under which warm-core and warm-ring thermal structures can rapidly develop in a tropical cyclone and the conditions under which a steady state can be approached. Intellectual Merit. While climate simulation and numerical weather prediction usually rely on primitive equation models, understanding of the underlying atmospheric dynamics has come primarily from studies using simplified models. The research will create new filtered model tools for further understanding of atmospheric dynamics, especially in the tropical region. The knowledge gained from applying these models to the problems studied in this project will help answer a number of key questions concerning large-scale atmospheric dynamics and the rapid intensification of hurricanes. Broader Impacts. User-friendly software for the new filtered models will be developed during this project and will be made available to other researchers to facilitate additional studies of atmospheric dynamics. The graduate students involved in this work will receive training and experience which will help prepare them for careers in research. The increased knowledge of fundamental large-scale dynamics and fundamental hurricane dynamics gained from this project should someday contribute to an improved ability to predict both large-scale tropical weather patterns and the mesoscale patterns that lead to changes in hurricane intensity.

这项研究的目的是通过开发和应用被过滤模型来提高对热带气氛的动态的了解。 过滤模型是简化的动力学模型，描述了低频大气运动，但不允许自由传播惯性 - 重力波。 该项目以热带动力学的主要研究者（PI）的研究专业知识为基础，并提高了他以前的工作。 该项目有两个主要部分，两者都涉及将过滤模型应用于热带气氛。 第一部分着重于大规模的热带动力学，涉及要使用的新型和改进的过滤模型的理论发展。 第二部分利用基于现有过滤模型的理论，并专注于飓风动态。 Longwave模型是一种专为大型热带应用而设计的现有过滤模型，它一直是热带研究的重要工具。 它准确地描述了开尔文波和长罗斯比波，但缺乏扭曲了短的罗斯比波。 在该项目的第一部分中，PI将改善Longwave模型，从而为热带研究社区提供一个重要的新工具，以了解大规模的热带运动。 此外，他将概括这个在赤道β平面理论框架中开发的新的过滤模型，以归为球体。 这将首次提供一个过滤的动力学模型，该模型可以准确地描述Rossby-Haurwitz波的全局PV动力学和开尔文波的非PV动力学。 在这些新过滤模型的许多可能的概括和应用中，将详细研究以下内容：（a）改进MJO的模拟； （b）生成拉普拉斯潮汐方程的准确分析解决方案； （c）“热带欧米茄方程式”的推导和解决方案，以了解与哈德利和沃克循环相关的垂直运动场； （d）射线追踪理论在球体上的衍生和应用，用于惯性 - 重力波和罗斯比 - 霍维茨波，目的是提高对中纬度 - 热带相互作用的理解； （e）开发用于地球物理湍流的新球体谐波（与球形谐波）分析工具的开发，其目的是将犀牛的屏障的概念从二维的波数字空间扩展到三维的波形空间。动力学，尤其是快速强化的过程。 在这里，PI将使用源自原始动量，连续性和热力学方程得出的地球趋势方程，以隔离在热带气旋中可以快速发展的温核和温暖的热圈热结构的条件，以及可以接近稳态的条件。智力优点。 尽管气候模拟和数值天气预测通常依赖于原始方程模型，但对潜在大气动力学的理解主要来自使用简化模型的研究。该研究将创建新的过滤模型工具，以进一步了解大气动态，尤其是在热带地区。 从将这些模型应用于该项目研究的问题中获得的知识将有助于回答有关大规模大气动态和飓风快速加强的许多关键问题。更广泛的影响。 在此项目期间，将开发针对新的过滤模型的用户友好软件，并将提供其他研究人员，以促进大气动态的其他研究。 参与这项工作的研究生将获得培训和经验，这将有助于他们为研究的职业做好准备。 从该项目中获得的基本大规模动力学和基本飓风动态的知识越来越多，有一天应该有助于提高预测大型热带天气模式和中尺度模式的能力，并导致飓风强度的变化。