3D reconstruction of typhoon Trami 2018 eye and eyewall clouds from airborne imaging.

Abstract

Typhoons cause significant damage and casualties worldwide, making accurate intensity estimation essential for risk mitigation. However, analyzing typhoons-particularly their size, cloud formations, and development rate-is challenging due to their unpredictable nature and various environmental influences. Cloud morphology, particularly the cloud-top altitude difference between the eyewall and the eye, is a key indicator of typhoon intensity, as suggested by the Dvorak technique. Traditionally, this information is derived from thermal infrared (TIR) measurements, but these are often unreliable due to atmospheric temperature inconsistencies. In this research, we developed a method using stereo-photogrammetry to analyze typhoons through aircraft-captured images of the typhoon eye. We reconstructed a 3D model of 2018 Typhoon Trami's eye, achieving a high resolution of 6.08 meters per pixel with a minimal projection error of 2.37 pixels. This model surpasses the resolution of satellite and radar sensors traditionally used for typhoon analysis. The model revealed a stair-step cloud structure likely associated with an eyewall replacement cycle occurring at that time. This technique allows for precise cloud-top height measurement, crucial for estimating typhoon intensity. Our findings were validated by comparing three cross-sections of the 3D model with TIR data from the Himawari-8 satellite and dropsonde measurements.