Diabatic Ekman Turbulence

热带大气的环流在一定程度上是由强自转区域或涡旋湍流组成的。其中一些地区发展成为热带气旋。将开发一个基本的流体动力学模式，该模式捕捉允许热带大气中出现相干涡旋结构的基本过程，即非绝热Ekman湍流模型。与更简单的模式(浅水或两层准地转)不同，它可以代表热带气旋形成所必需的两个过程：埃克曼抽水和风致地表热交换(WISHE)。利用该模式进行的初步数值实验表明，非绝热Ekman湍流可以自发地自组织成强烈的飓风状涡旋。将开展两个方面的研究。第一个是研究相干结构的出现，重点是在给定的参数设置下实现摩擦辐射对流平衡的可预测性。初步结果表明，相同的参数设置可以得到不同涡数和强度的离散准平衡态。将探索平衡态的依赖性及其对初始条件和参数设置的可预测性。第二个活动是研究非绝热Ekman湍流模式中的动力机制，包括导致单个气旋加强的机制，产生涡旋合并和涡旋对称化的过程，以及波和涡间的相互作用。这项工作的更广泛的影响与热带气旋的发展和发展有关，可能对它们的统计预报有影响。该模型将被开发为一种教育工具。一名学生将通过与华盛顿大学的合作参与这项研究。

The circulation of the tropical atmosphere is, in part, organized by regions of strong rotation, or vortical turbulence. Some of these regions develop into tropical cyclones. A fundamental fluid dynamical model will be developed, which captures the essential processes that allow coherent vortical structures to emerge in the tropical atmosphere, the diabatic Ekman turbulence model. Unlike simpler models (shallow water or two-level quasigeostrophic) it can represent two processes that are necessary for the formation of tropical cyclones, Ekman pumping and wind-induced surface heat exchange (WISHE). Preliminary numerical experiments using this model demonstrate that diabatic Ekman turbulence can spontaneously self-organize into intense hurricane-like vortices. Two lines of research will be carried out. The first is to study the emergence of coherent structures, focusing on the predictability of the frictional radiative convective equilibrium that is achieved with a given parameter setting. Preliminary results indicate that the same parameter settings can result in discrete quasi-equilibrated states with different numbers and intensities of vortices. The dependence of the equilibrated states and their predictability on the initial conditions and the parameter settings will be explored. The second activity is a study of the dynamical mechanisms that operate in the diabatic Ekman turbulence model, including those that give rise to the intensification of individual cyclones, the processes that produce vortex mergers and vortex symmetrization, and the interactions between waves and vortices.Broader impacts of this work are in its relevance to the development and growth of tropical cyclones, with possible implications for their statistical prediction. The model will be developed as an educational tool. A student will be involved in the research through a collaboration with the University of Washington.