Dynamics of Spatio-Temporal Complexity: Baroclinic Flows at Moderate to Large Supercriticality

时空复杂性动力学：中到大超临界度下的斜压流

• 批准号: 9523479
• 负责人: Michael Mundt
• 金额: $ 9.93万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-01-15 至 1996-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9523479&HistoricalAwards=false
• 关键词: Dynamics; Spatio; Temporal; Complexity; Baroclinic

9523479 Mundt and Vallis Numerical and laboratory simulations of baroclinic flows have revealed that moderately supercritical baroclinic systems can exhibit a wide range of behavior (e.g., steady, periodic, chaotic). Moreover, aperiodic, temporally-irregular solutions can exist even when the flow is only marginally unstable, that is, at small values of supercriticality. Most previous dynamics studies have been directed to studying this parameter range which corresponds to lower driving than is geophysically realistic. Studies in more realistic parameter ranges are usually conducted with more complex models and have provided more empirical results, often relying on statistical descriptions, rather than a more thorough understanding of the dynamics. Thus, little is known about the transition from chaos to turbulence in the supercriticality range characteristic of atmospheric flows. The principal investigators will carry out a study focused on the complexity (disorder) of flows with increasing supercriticality, guided by their hypothesis that the level of mean flow supercriticality is directly related to the disorder of the eddy flow. They will explore the extent to which behavior observed at low supercriticality is also observed at more geophysically realistic ranges of supercriticality. Models of varying complexity will be employed, although the initial effort will focus on a two layer, quasi-geostrophic model. A variety of analysis tools, from empirical orthogonal function analysis to wavelet analysis, will be employed. The importance of this study lies in the potential for better understanding of the variability of the atmosphere, and has important implications a wide range of weather and climate issues, including weather regime transitions and parameterization of meridional heat flux in climate models. ***

9523479穆特和瓦利斯 斜压流的数值模拟和实验室模拟已经揭示，中等超临界斜压系统可以表现出广泛的行为（例如，稳定的、周期性的、混沌的）。 此外，即使当流动只是轻微不稳定时，即在小的超临界值时，也可能存在非周期性、时间不规则的解。 大多数以前的动力学研究已被定向到研究该参数范围，该参数范围对应于比实际驾驶更低的驾驶。 在更现实的参数范围内进行的研究通常使用更复杂的模型，并提供了更多的经验性结果，往往依赖于统计描述，而不是对动态的更透彻的理解。 因此，很少有人知道从混乱到湍流的过渡在超临界范围内的大气流动的特点。 主要研究人员将进行一项研究，重点是随着超临界性的增加，流动的复杂性（无序），他们的假设，即平均流超临界性的水平直接关系到涡流的无序。 他们将探索在低超临界状态下观察到的行为在多大程度上也可以在更接近实际的超临界状态范围内观察到。 将采用不同复杂程度的模式，虽然最初的努力将集中在一个两层，准地转模式。 将采用从经验正交函数分析到小波分析的各种分析工具。 这项研究的重要性在于有可能更好地了解大气的变异性，并对广泛的天气和气候问题，包括天气状况转换和气候模式中纬向热通量的参数化具有重要意义。 ***