Mechanisms for Hurricane Motion and Intensity Change

在过去的几十年里，人们对影响飓风运动和强度的因素进行了深入的研究，从而提高了知识和预报能力。 然而，关于飓风内核的过程以及它们在决定热带系统的强度和路径方面可能发挥的作用，仍然存在一些基本问题。 该项目将重点关注围绕飓风中心移动的大气波，并可能影响强度和雨带。 这项工作的主要社会影响将是提高对热带气旋基本过程的认识，以改进强度和路径预报。 一名学生将直接参与该项目，从而确保知识转移给下一代科学家。研究小组将对飓风中可能影响其方向和强度变化的小尺度运动进行理论和建模研究。 该项目的重点是涡罗斯贝波（VRW），它可以由对流或热带气旋运动激发。 这些VRW将角动量向内输送，波能向外输送，可能是螺旋雨带形成的基础。 该项目将利用两个现有的热带气旋动力学简单模型，一个线性模型和一个时域模型。 本课程将探讨热带气旋中的VRW的四个方面：1）正压非辐散模式中对流强迫波数为1的涡卷及其与涡运动的相互作用，2）球形地球上无界涡的逻辑不一致性，3）当波数为n的非对称辐合与波数为n的涡度相互作用产生对称和波数为2n的涡度时涡度源的校正，4）内波导中对流强迫波的三维建模

The factors that impact hurricane motion and intensity have been deeply studied over the past few decades, with resulting improvement in knowledge and forecasting ability. However, there are still basic questions about processes in the inner core of a hurricane and the role they may play in determining the strength and track of tropical systems. This project will focus on atmospheric waves that move around the center of a hurricane and potentially impact intensification and rain bands. The main societal impact of this work will be to improve understanding of a basic process in tropical cyclones with a goal of improving intensity and track forecasts. A student will be directly involved with the project, thus ensuring the transfer of knowledge to the next generation of scientists.The research team will conduct a theoretical and modeling study into the small-scale motions within a hurricane which may affect their direction and intensity change. The project is focused on Vortex Rossby Waves (VRWs) which can be excited by convection or tropical cyclone motion. These VRWs transport angular momentum inward and wave energy outward, and may underlie spiral rain band formation. The project will make use of two existing simple models of tropical cyclone dynamics, a linear model and a time-domain model. Four aspects of VRWs in tropical cyclones will be investigated: 1) Convectively forced wavenumber-1 VRWs and their interaction with vortex motion in a Barotropic Non-Divergent (BND) model, 2) Logical inconsistency of unbounded vortices on a spherical Earth, 3) Rectification of vorticity sources when wavenumber-n asymmetric convergence interacts with wavenumber-n vorticity to generate symmetric and wavenumber-2n vorticity, 4) Three-dimensional modeling of convectively forced waves in the inner waveguide