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.

该项目将研究与气旋-反气旋不对称性相关的动力学，即为什么与较弱和更广泛的反气旋相比，气旋往往具有更大的振幅和孤立的核心。 该研究将基于一个理想化的理论框架，该框架在罗斯比数展开中的准地转（QG）模型之外有效，即 QG+1 系统。 PI 将扩展他之前对以对流层顶为边界的 QG+1 系统的研究，此外还包括一个刚性表面作为另一个边界，从而在系统中具有两个边界（因此命名为 2sQG+1 系统）。 PI 将测试 2sQG+1 系统的控制参数是两个边界之间的距离的假设，因为它将调节斜压和正压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，气旋向较大尺度的能量传递较弱，因此将保持仅限于边界的稳健结构，而反气旋则具有较强的高级能量传递，将跨越整个边界。对流层。 这些假设有助于解释自然界中气旋-反气旋的不对称性。 然后，理想化的理论建模工作将通过国家环境预测中心 (NCEP) 的分析数据和极地低气压的统计数据进行测试。这些结果有可能提高我们对斜压和正压动力学之间的尺度相互作用以及气旋-反气旋不对称性质的理解。 计划中的研究将为研究生学习提供良好的教育机会。