Collaborative Research: Understanding the Turbulent Dynamics of Convective Bursts and Tropical Cyclone Intensification Using Large Eddy Simulations and High-Order Numerics

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。飓风强度的变化是由一系列复杂和相互竞争的过程控制的，这些过程很难模拟。该项目将解决飓风强度的关键不确定性之一，即飓风内核中空气和水分的湍流混合。特别是，这项研究将集中在对流爆发上，它大致相当于飓风眼壁附近的大雷暴，以及它们如何影响增强周期。在最近的许多高影响风暴中都发生了快速强化的变化，虽然预报员知道可能导致快速强化的一般条件，但这些变化的确切时间和幅度很难预测。这项研究将为科学界提供额外的信息，这可能会改善这些风暴的数值模拟。该项目还将为一些学生提供培训和推广机会，从而培养下一代科学家。该项目的目标是了解热带气旋增强的基本物理学，重点是湍流动力学的作用。研究人员的目标是：1)了解对流爆发周期在增强过程中从形成到成熟和衰减的湍流性质；2)确定轴对称和非对称动力学在以大范围能量长度尺度和最小耗散动力核心为特征的完全湍流状态下热带气旋的增强中所起的作用。为了实现这些目标，研究人员计划使用新开发的climatemmachine社区模型，在50米的水平和垂直网格间距上对热带气旋进行高分辨率的大涡模拟（LES）。模型输出将使用欧拉和拉格朗日参考中的角动量、动能和热能方程的诊断预算计算进行分析，以提高物理洞察力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Hurricane intensity changes are governed by a number of complex and competing processes that are difficult to simulate. This project will address one of the key uncertainties in hurricane intensity, the turbulent mixing of air and moisture in the inner core of a hurricane. In particular, the study will focus on convective bursts, which are roughly equivalent to large thunderstorms near the hurricane’s eyewall, and how they influence the intensification cycle. Rapid intensification changes have occurred in many recent high-impact storms and while forecasters know the general conditions that may lead to rapid intensification, the exact timing and magnitude of those changes are difficult to predict. This research will provide additional information to the scientific community which may result in improved numerical modeling of these storms. The project will also provide training and outreach opportunities to several students, thereby training the next generation of scientists.The goal of the project is to understand the fundamental physics of tropical cyclone intensification with an emphasis on the role of turbulent dynamics. The researchers aim to 1) understand the turbulent nature of the convective burst cycle from formation to maturation and decay during intensification, and 2) identify the roles of axisymmetric and asymmetric dynamics in the intensification of tropical cyclones in a fully turbulent regime characterized by a wide range of energetic length scales with a minimally dissipative dynamic core. To address these aims, the researchers plan to conduct very high-resolution Large Eddy Simulations (LES) of tropical cyclones at 50m horizontal and vertical grid spacing using the newly developed ClimateMachine community model. The model output will be analyzed using diagnostic budget calculations for angular momentum, kinetic energy, and thermal energy equations in a Eulerian and Lagrangian reference from to enable improved physical insight.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.