Collaborative Research: Nonlinear Stability of Zonally Varying Flows

这项研究的目标是更好地了解嵌入在纬向变化的基本气流中的大气扰动的非线性动力学和演变。这项研究将使用贝塔平面上的两层斜压模式和球坐标正压模式进行。两层模式将使PIS能够检查斜压、正压和地形过程，并评估它们在确定纬向气流和波浪扰动的区域特征和时间变异性方面的综合作用。使用正压模型的研究将评估使用球面几何来模拟这些类型的流动的影响。在弱非线性的情况下，将使用渐近展开和多个空间和时间尺度来解析地获得模型解。在这一限制之外，将使用谱变换方法来获得数值解。这些研究可能为观测到的大气特征，如区域气旋发生、阻塞和低频变化提供进一步的洞察。这个项目是与爱荷华州立大学的特伦斯·内森博士合作进行的，由美国国家科学基金会资助ATM-8813296。

The goal of this research is to better understand the nonlinear dynamics and evolution of atmospheric disturbances embedded in a zonally varying basic flow. The research will be done using a two-layer baroclinic model on the beta-plane and a spherical coordinate barotropic model. The two-layer model will allow the PIs to examine baroclinic, barotropic and topographic processes and to assess the their combined role in determining the regional character and time variability of the zonal flow and wave disturbances. The research with the barotropic model will to assess the impact of using spherical geometry in simulating these types of flows. In cases of weak nonlinearity, model solutions will be obtained analytically using asymptotic expansions and multiple space and time scales. Outside this limit, spectral transform methods will be used to obtain solutions numerically. These investigations may provide further insight into such observed atmospheric features as regional cyclogenesis, blocking, and low frequency variability. This project is being carried out in collaboration with Dr. Terrence Nathan, Iowa State University, under NSF grant ATM-8813296.