Investigating the Large-Scale Transport of a Volcanic Plume and the Impact on a Secondary Site

David Jean Du Preez,Hassan Bencherif,Caradee Yael Wright,Rebecca F Hoffman,Nelson Bègue,Lieven Clarisse

doi:10.3390/atmos11050548

Abstract

Volcanic plumes can be transported across vast distances and can have an impact on solar ultraviolet radiation (UVR) reaching the surface due to the scattering and absorption caused by aerosols. The dispersion of the volcanic plume from the Puyehue-Cordón Caulle volcanic complex (PCCVC) eruption was investigated to determine the effect on aerosol loading at Cape Point, South Africa. The eruption occurred on 4 June 2011 and resulted in a plume reaching a height of between 9 and 12 km and was dispersed across the Southern Hemisphere. Satellite sulphur dioxide (SO2) observations and a dispersion model showed low concentrations of SO2 at the secondary site. However, satellite observations of volcanic ash and ground-based aerosol measurements did show increases between 10 and 20 June 2011 at the secondary site. Furthermore, there was good agreement with the dispersion model results and observations from satellites with most of the plume located between latitudes 40°–60° South.

Highlights

Volcanic eruptions can eject a highly reactive mix of aerosols and gases into the atmosphere [1].Some of the main gases associated with volcanic activity are water vapour (H2 O), carbon dioxide (CO2 ), sulphur dioxide (SO2 ), hydrogen sulphide (H2 S) and hydrochloric acid (HCl) [2]
The umbrella cloud and the rising plume were both affected by the prevailing westerly winds, showing the significant effect that the wind had on the dispersion of the aerosols and ash, some of the spreading was due to physical processes in the plume such as density-driven mechanisms [10]
Aerosol optical depth (AOD) data (2011 to 2018, inclusive) from a precision filter radiometer (PFR) located at Cape Point were used to identify any anomalies in AOD as a result of the volcanic plume

Summary

Introduction

Volcanic eruptions can eject a highly reactive mix of aerosols and gases into the atmosphere [1]. SO2 is suspended in the troposphere for only a short period of time, but SO2 injected into the stratosphere through volcanic eruptions can remain there for up to three years as sulphuric acid aerosols [3,4]. Atmosphere 2020, 11, 548 acid (H2 SO4 ) These H2 SO4 aerosols have a radiative effect during eruptions [6]. During volcanic eruptions the aerosol loading and size distribution are modified by injected ash particles [7]. By 14 June 2011, the plume had circumnavigated the Southern Hemisphere and reached the original eruption site [4]. The umbrella cloud and the rising plume were both affected by the prevailing westerly winds, showing the significant effect that the wind had on the dispersion of the aerosols and ash, some of the spreading was due to physical processes in the plume such as density-driven mechanisms [10]. The trajectory and dispersion of the plume was investigated using satellite observations and model output to determine whether the plume did reach the secondary site and whether or not SO2 anomalies at the secondary site could be attributed to the volcanic eruption

Data and Methods

Methods

Results and Discussion

Conclusions