Optical properties of volcanic aerosols from eruptions of Nishinoshima Island observed in Southern Taiwan

Abstract

In July-August 2020, the volcano on Nishinoshima Island erupted with a moderate scale. The emitted aerosols arrived in Taiwan in early August and caused hazy air conditions in a few cities. In the city of Kaohsiung (KS) in southern Taiwan, the volcanic aerosols were observed with a combination of the aerosol robotic network (AERONET), several ground monitoring stations, and a lidar system. Increasing aerosol loadings were observed, beginning on 5 August 2020, based on a ground PM10/PM2.5 and the aerosol optical depth (AOD) of AERONET. Lidar measurements showed strong aerosol layers at heights of 0-2 km comparable to AERONET AOD. Optical properties including AOD, Angström exponent (AE), lidar backscattering coefficient, and depolarization ratio are measured with the source investigated using the back and forward trajectory studies.