Tropical Cyclones Reduce Ozone in the Tropopause Region Over the Western Pacific: An Analysis of 18 Years Ozonesonde Profiles

Abstract

Typhoons play a key role in causing low ozone concentrations in the upper troposphere and lower stratosphere (UTLS) over the western Pacific. In this study, 18 years records (2000–2017) of balloon-borne ozone measurements in Hong Kong (22.3°N, 114.2°E) and Naha (26.2°N, 127.7°E) are combined with trajectory calculations to quantitatively assess the impact of western Pacific typhoons on ozone in the UTLS. The results show that 46.3% (44.9%) of the ozone profiles in Hong Kong (Naha) are impacted by western Pacific typhoons from July to October, with negative ozone anomalies exceeding −20%. Vertical transport by intense typhoons affects 16.8% (18.8%) of the ozone profiles in Hong Kong (Naha) with even larger negative anomalies (