New Methods in Storm Track Dynamics Theory

风暴轨迹动力学理论的新方法

• 批准号: 0736022
• 负责人: Brian Farrell
• 金额: $ 45万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0736022&HistoricalAwards=false
• 关键词: New; Methods; Storm; Track; Dynamics

An important unsolved problem in atmospheric dynamics is how the jets in the atmosphere emerge spontaneously from turbulence. In this project, Farrell and his group will develop, and explore the implications of, a new theory of jets, using an analytical theory, that builds on their previous work in stochastic dynamics (the dynamics of randomly forced systems, like turbulent fluid flows). In this theory, the turbulent eddies, which are the familiar highs and lows of weather maps, are treated as randomly forced perturbations to the zonally averaged flow. With the assumption that these eddies are small perturbations, such that their equations are linear, a closed self-consistent theory for the emergence of jets can be developed.Preliminary results from the theory show that it predicts the scales and structures of jets in good agreement with those observed in Earth's atmosphere. In the present project, this work will be extended by:. Exploring how the jets and their stability depend upon the parameters of the problem: the strength of the stochastic forcing and the values of dissipation parameters.. Generalizing the problem to include meridional dependence, so as to treat the problem of an eddy-driven polar jet coexisting with the subtropical jet.. Generalizing the problem to non-zonally symmetric jets, so as to treat the problem of the zonally isolated jets and storm tracks of the Northern Hemisphere.The broader impacts of this project are in obtaining a deeper and more general understanding of the climate system. For example, abrupt changes in climate may be associated with abrupt changes in jet regimes that are described by this theory. A graduate student will be supported.

大气动力学中一个尚未解决的重要问题是大气中的喷流是如何从湍流中自发产生的。在这个项目中，法雷尔和他的团队将开发，并探索的影响，一个新的理论射流，使用分析理论，建立在他们以前的工作在随机动力学（随机强迫系统的动力学，如湍流）。在这个理论中，湍流涡旋，这是熟悉的高和低的天气图，被视为随机强迫扰动纬向平均流量。假设这些涡是小扰动，使得它们的方程是线性的，就可以发展出一个封闭的自洽理论来描述喷流的出现，初步结果表明，它预测的喷流的尺度和结构与地球大气中观测到的结果非常一致。在本项目中，这项工作将通过以下方式加以扩展：探索射流及其稳定性如何依赖于问题的参数：随机强迫的强度和耗散参数的值。将问题推广到包含副热带相关性，从而处理涡驱动的极区急流与副热带急流共存的问题。将问题推广到非纬向对称急流，以便处理北方纬向孤立急流和风暴路径的问题。这个项目的更广泛的影响是获得对气候系统更深入和更普遍的了解。例如，气候的突然变化可能与该理论所描述的急流状态的突然变化有关。研究生将得到支持。