Observed eccentric eyewall structure in Super Typhoon Doksuri (2023) and its potential impact on intensity change

Abstract Multi-source observations revealed an atypical double-eyewall structure in Super Typhoon Doksuri (2023), which we define herein as an ‘eccentric eyewall’. Ultimately, the structure evolved into the more familiar concentric eyewall (CE). Our findings indicate that the transition from an eccentric to a CE structure in Doksuri (2023) coincided with its preceding weakening stage and subsequent rapid intensification (RI) stage, facilitated by a favorable large-scale environmental context over the South China Sea. Unlike previous observations, this RI involved the simultaneous strengthening of both eyewalls rather than a typical eyewall replacement cycle. Simultaneously, the vortex centers in the upper, middle, and lower troposphere showed counterclockwise rotation and gradually aligned vertically, providing evidence of enhanced tropical cyclone (TC) vortex axisymmetry. These findings could deepen our understanding of TC fine structure evolution and the mechanisms behind TC intensity changes.