A072-07
Simulation of Raikoke Eruption 2019: Aerosol dynamic processes and aerosol-radiation interaction improve volcanic plume dispersion

Wednesday, 9 December 2020: 10:54
Virtual
Lukas Muser1, Ali Hoshyaripour1, Julia Bruckert1, Akos Horvath2, Elizaveta Malinina3, Sandra Peglow4, Fred J Prata5, Alexej Rozanov6, Christian von Savigny4, Heike Vogel1 and Bernhard Vogel1, (1)Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Karlsruhe, Germany, (2)University of Hamburg, Hamburg, Germany, (3)University of Bremen, Intitute of Environmental Physics, Bremen, Germany, (4)University of Greifswald, Greifswald, Germany, (5)AIRES Pty. Ltd., Mt Eliza, Australia, (6)University of Bremen, Institute of Environmental Physics, Bremen, Germany
Recorded Presentation
Abstract:
Volcanic aerosols, such as ash and sulfate, jeopardize air traffic and influence weather and climate. State-of-the-art atmospheric models enable global aerosol dispersion forecasts, however, neglect aerosol dynamic processes and aerosol-radiation interaction. Processes which have a direct influence on particles’ lifetime in the atmosphere.

We extended the ICOsahedral Nonhydrostatic – Aerosols and Reactive Trace gases (ICON-ART) modeling system by including aerosol dynamic processes and aerosol-radiation interaction. The aerosol dynamic processes comprise secondary aerosol formation and coagulation of particles which generates internally mixed aerosols. Furthermore, the radiation feedback of these mixed particles is modeled. This is accomplished with the development and implementation of the novel aerosol module AERODYN (AEROsol DYNamic).

More specifically, a simplified OH chemistry scheme converts (volcanic) SO2 into sulfuric acid, which in turn can nucleate into sulfate particles or condense onto existing aerosol particles. Optical properties of these internally mixed particles are determined for a core-shell mixing state using Mie theory.

Using this AERODYN module, we simulate the dispersion of volcanic aerosols after the Raikoke eruption in June 2019. Additionally, we compare the simulation results with measurements from state-of-the-art satellite instruments (AHI, TROPOMI, CALIOP, OMPS-LP).

Based on our model results, aerosol dynamic processes remove approximately 50% mass of particles with diameter d < 30 µm (very fine volcanic ash). In contrast, due to aerosol-radiation interaction the maximum volcanic cloud top height climbs up 6 km over the 4 days following the eruption. For the first time we simulated the combined effects of aerosol dynamic processes and aerosol-radiation interaction. With this, the forecast of very fine ash lifetime in the atmosphere is more accurate for the case of the Raikoke eruption in 2019.

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