Tensor Analysis of Tropical Cyclone Boundary Layer Turbulence

Abstract

Turbulent momentum transport critically influences tropical cyclone (TC) structure and intensity, but its multiscale characteristics remain poorly understood. Using two large eddy simulations, we investigate the Reynolds stress tensor and subfilter‐scale momentum flux tensor during rapid intensification and mature stages of an idealized TC. We find that both tensor type exhibit similar spatial patterns. The mean horizontal momentum fluxes have comparable or greater magnitudes than vertical fluxes, highlighting their essential contribution to angular momentum redistribution. The horizontal components of diffusive tendencies contribute at magnitudes comparable to the vertical components. Alignment analysis using tensor decomposition demonstrates that strain‐rotation interactions dominate turbulent stress transporting in the boundary layer, highlighting limitations in the classical Boussinesq hypothesis. These results highlight the need for turbulence closures that incorporate rotational effects.