2026/06/08 by Yiting Zhu, Yuqing Wang
Earth and Planetary Sciences · Environmental Science · #Tropical and Extratropical Cyclones Research #Coastal wetland ecosystem dynamics #Ocean Waves and Remote Sensing
paper · doi:10.1175/mwr-d-25-0215.1
Abstract Air–sea interaction plays an important role in tropical cyclone (TC) intensity and structural evolution. However, how air–sea interaction, including the uncertainties in surface drag coefficient ( C D ) parameterizations, modulates ocean feedback and secondary eyewall formation (SEF) in TCs remains incompletely understood. In this study, coupled and uncoupled numerical experiments of Hurricane Patricia (2015) are conducted using two C D schemes: the default parameterization (CTRL) and the Donelan formulation (Donelan18). In the uncoupled simulations, CTRL produces stronger surface stress within the primary eyewall, whereas Donelan18 yields relatively larger C D outside the eyewall, favoring enhanced outer rainband convection and secondary eyewall development at smaller radii. When coupled with a three-dimensional ocean mixed-layer model [three-dimensional Price–Weller–Pinkel (3DPWP)], the evolution of both the primary and secondary eyewalls becomes more complex through distinct sea surface temperature (SST) cooling pathways. In CTRL3DPWP, enhanced inner-core stress leads to localized SST cooling, reduced surface enthalpy fluxes, and a more rapid weakening of the primary eyewall, while strengthened inflow at larger radii supports an outward-shifted SEF that is more consistent with observations. In contrast, Donelan183DPWP produces broader outer-core cooling that stabilizes the boundary layer and partially offsets the dynamical advantages of the drag formulation, suppressing secondary eyewall intensification. These results indicate that the radial distribution of C D modulates both intrinsic TC structure and the coupled ocean feedback pathways that influence SEF. Improving drag parameterizations in a manner consistent with coupled air–sea processes is therefore important for enhancing predictions of TC structural evolution and intensity change.