Examining Storm Asymmetries in Recent Tropical Cyclones Using Polarimetric Radar Observations

This study examines the microphysical structures of tropical cyclone precipitation in recent storms observed by the dual-polarization WSR-88D radar network. We focus on three storms: Arthur 2014, Matthew 2016, and Irma 2017. We analyze the distribution and evolution of polarimetric variables to characterize the precipitation processes of the primary eyewall, secondary eyewall, and rainbands in each storm. These inner core features, particularly their asymmetric structures, are often organized by a larger-scale factor, such as deep-layer environmental wind shear or track motion. We thus analyze these datasets by the shear and track motion vectors and compare these results with the expected asymmetric wind field, which impacts and interacts with the observed microphysical structures and processes. Our results highlight the convective/stratiform evolution in rainband convection, size sorting of hydrometeors in the eyewall, stratiform dynamics of secondary eyewall formation, and asymmetric concentric eyewalls in eyewall replacement. This investigation also uses a combination of airborne Doppler radar observations and numerical modeling to further assess the observed microphysical features. The results provide new microphysical insight to the interconnected physical processes that govern the intensity, structure, and precipitation of tropical cyclones.