Balanced Dynamics and Cyclone-Anticyclone Asymmetry

平衡动力学和旋风-反旋风不对称

• 批准号: 0228804
• 负责人: Gregory Hakim
• 金额: $ 24.99万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0228804&HistoricalAwards=false
• 关键词: Balanced; Dynamics; Cyclone; Anticyclone; Asymmetry

This project will investigate the dynamics associated with the cyclone-anticyclone asymmetry, namely, why cyclones tend to have larger amplitude and isolated cores in comparison to weaker and broader anticyclones. The research will be based on an idealized theoretical framework that is valid an order beyond the quasigeostrophic (QG) model in the Rossby number expansion, i.e., the QG+1 system. The PI will extend his prior study on the QG+1 system that has the tropopause as a boundary to include, in addition, a rigid-surface as another boundary to have two boundaries in the system (thus named a 2sQG+1 system). The PI will test the hypothesis that the control parameter of the 2sQG+1 system is the distance between the two boundaries in that it would regulate the relative importance of baroclinic and barotropic dynamics. The second hypothesis to be tested is that the 2sQG+1 system will show that cyclones have a weaker energy transfer to larger scales and thus will maintain robust structures confined to the boundaries, whereas anticyclones, which have a strong upscale energy transfer, will span the troposphere. These hypotheses serve to provide explanations of the cyclone-anticyclone asymmetry in nature. The idealized theoretical modeling work will then be tested with the National Center for Environmental Prediction (NCEP) analysis data using the statistics of polar lows. The results have the potential of improving our understanding of scale interactions between baroclinic and barotropic dynamics, and nature of cyclone-anticyclone asymmetry. The planned research will provide good educational opportunities for graduate studies.

该项目将研究与旋风 - 抗气管不对称性相关的动力学，即，与较弱和较宽的反气旋相比，旋风倾向于具有更大的振幅和孤立的核心。 该研究将基于理想化的理论框架，该框架在Rossby数字扩展（即QG+1系统）中有效的秩序有效。 PI将扩展他对QG+1系统的先前研究，该系统具有对流层顶作为边界，还包括一个刚性表面作为另一个边界，以在系统中具有两个边界（因此被称为2SQG+1系统）。 PI将检验以下假设：2SQG+1系统的控制参数是两个边界之间的距离，因为它将调节斜力和压缩动力学的相对重要性。 要测试的第二个假设是2SQG+1系统将表明旋风的能量转移较弱，因此将保持局限于边界的稳健结构，而具有强大的高档能量转移的反气旋将跨越对流层。 这些假设提供了自然界中旋风 - 抗气管不对称性的解释。 然后，将使用Polar Lows的统计数据对理想化的理论建模工作进行测试。结果可能会提高我们对斜视和压缩动力学之间比例相互作用的理解，以及旋风 - 抗气管不对称性的性质。 计划的研究将为研究生学习提供良好的教育机会。