High-resolution USTC (University of Science and Technology of China) Ozone Lidar observations at Yangbajing, Tibet capture short-lived rapid STE (stratosphere-to-troposphere exchange)-related ozone descent for the first time. Lidar temperature profiles link these events to tropopause thermal variability unresolved by conventional models. Wei’s flux diagnostic and PV (potential vorticity)-threshold sensitivity identify 3 PVU (potential vorticity units) as optimal. ERA5 shows gravity-wave modulation during tropopause folding, and lidar ozone profiles are used to quantify instantaneous cross-tropopause ozone flux.