Evolution of aerosol plumes from 2019 Raikoke volcanic eruption observed with polarization lidar over central China

Abstract

The Raikoke volcano erupted on 21–22 June 2019 and emitted large amounts of volcanic ash into the upper troposphere, and later might impose long-term effects on the global and regional radiation budget after the long-range transport of volcanic aerosol plumes. Height-resolved ground-based lidar observations are beneficial to trace and cross-check the 3-D evolution of complicated aerosol plumes, which are, however, scarce at mid-latitude regions. Here, we present a rare ground-based lidar observation of Raikoke aerosol plumes in the mid-latitudes of the Northern Hemisphere (site: Wuhan; location: 30.5°N, 114.4°E) from 25 July to 30 September 2019. The main aerosol plume first arrived at Wuhan on 25 July and was intermittently observed during the following 2 months at altitudes of 15.0–20.5 km. From 22 August to 23 September, this aerosol plume underwent two quasi-elliptical transport pathways in East Asia driven by an Asian monsoon anticyclone. The particle depolarization ratio of volcanic aerosols is < 0.05. The layer-integrated AODs (aerosol optical depths) of 0.001–0.017 are smaller than those observed from other high-altitude sites previously owing to the dispersal of particles. Interestingly, another separated dense aerosol cloud was observed twice, closely followed by a thin and horizontally extended aerosol plume (named ‘trail’). This study provides valuable information for studying the evolution of the vertical distribution and optical properties of Raikoke volcanic aerosols, which is anticipated to be a crucial supplement/reference for dispersion model simulation, data assimilation, and forecasting refinement.