The Control of Tropical Cyclone Wind Structure on Inner and Outer Rainband Formation: A Balanced Dynamics Perspective.

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Bibliographic Details
Title:	The Control of Tropical Cyclone Wind Structure on Inner and Outer Rainband Formation: A Balanced Dynamics Perspective.
Authors:	Yang, Bolei^1,2 (AUTHOR) yang.bolei@nju.edu.cn
Source:	Journal of the Atmospheric Sciences. May2026, Vol. 83 Issue 5, p1-17. 17p.
Subjects:	Tropical cyclones, Windstorms, Steady-state flow, Fluid mechanics
Abstract:	Inner and outer rainbands are ubiquitous features of tropical cyclones (TCs) and can induce significant intensity fluctuations. While previous studies have indicated that broad TC wind profiles favor outer rainbands and narrow profiles favor inner rainbands, the underlying dynamical mechanism has remained unclear. This study elucidates this relationship using idealized simulations and the Sawyer-Eliassen equation. We demonstrate that a narrow wind profile's response to eyewall heating is a strong, low-level convergence in the inner core, which sustains inner rainbands. In contrast, a broad wind profile produces an inner-core divergence and outer-core convergence, thereby promoting a subsident moat and outer rainbands. This fundamental difference arises from how the radial gradient of inertial stability resists boundary layer inflow. This work provides a new axisymmetric dynamical perspective on TC rainband organization and secondary eyewall formation, highlighting the inertial stability gradient as a critical control. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	Inner and outer rainbands are ubiquitous features of tropical cyclones (TCs) and can induce significant intensity fluctuations. While previous studies have indicated that broad TC wind profiles favor outer rainbands and narrow profiles favor inner rainbands, the underlying dynamical mechanism has remained unclear. This study elucidates this relationship using idealized simulations and the Sawyer-Eliassen equation. We demonstrate that a narrow wind profile's response to eyewall heating is a strong, low-level convergence in the inner core, which sustains inner rainbands. In contrast, a broad wind profile produces an inner-core divergence and outer-core convergence, thereby promoting a subsident moat and outer rainbands. This fundamental difference arises from how the radial gradient of inertial stability resists boundary layer inflow. This work provides a new axisymmetric dynamical perspective on TC rainband organization and secondary eyewall formation, highlighting the inertial stability gradient as a critical control. [ABSTRACT FROM AUTHOR]
ISSN:	00224928
DOI:	10.1175/JAS-D-25-0185.1