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

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.