Analyzing coherent structures in the tropical cyclone boundary layer using large eddy simulations

Abstract

Turbulence within the tropical cyclone boundary layer plays a crucial role in the exchange of heat, moisture, and momentum between the surface and the atmosphere. This study investigates the characteristics of coherent structures, specifically streaks and rolls, using large eddy simulations. Our results highlight significant differences across the three radius cases, with smaller radius exhibiting more intense and organized turbulence and streak/roll structures. Our analyses reveal that thermodynamic conditions significantly impact the timing of initial streak/roll development but do not affect their intensity in the steady state. Wind structures closer to the tropical cyclone center lead to stronger and more rapidly developing streaks/rolls, indicating their critical role in determining the intensity and formation of these features. Sensitivity tests on the Coriolis parameter (f) and radial decay parameter of tangential wind (n) show minimal impact on the development of streaks/rolls, suggesting these factors are less influential compared to wind and thermodynamic conditions.

Keywords

• Tropical cyclone boundary layer
• Rolls
• Streaks
• Large eddy simulation