Impact of the Hunga eruption on polar stratospheric clouds as seen by the lidar observatory at Concordia Station

Abstract Concordia Station is a long-term lidar observatory in Antarctica. Its main purpose is to detect and classify polar stratospheric clouds (PSCs). In September 2023, water ice PSCs were observed for a period of 6 days. This has never occurred during the month of September in the 10 years of observations of PSCs at Concordia Station. In addition, the space-borne CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) lidar observed a rare occurrence of ice PSCs over Concordia Station during the first half of June. It is well known that the January 2022 eruption of the Hunga submarine volcano (20°32’S, 175°23’W) injected vast amounts of water vapour into the stratosphere. The Hunga hydration flooded southern high latitudes at the end of the 2022 austral winter, and the moist air was then entrained into the developing vortex in the austral autumn (April–May) of 2023. The increased water vapour from Hunga was reported to promote PSC formation by cooling the stratosphere and raising PSC formation temperatures. Here, we explore the impact of the Hunga eruption on the PSCs observed at Concordia Station.