Volcanic Emissions, Plume Dispersion, and Downwind Radiative Impacts Following Mount Etna Series of Eruptions of February 21–26, 2021

Pasquale Sellitto (1) , Giuseppe Salerno (2) , Stefano Corradini (3, 4) , Irène Xueref-Remy (5) , Aurélie Riandet (5) , Clémence Bellon (5) , Sergey Khaykin (6) , Gérard Ancellet (6) , Simone Lolli (7) , Ellsworth J. Welton (8) , Antonella Boselli (7) , Alessia Sannino (9) , Juan Cuesta (1) , Henda Guermazi (1) , Maxim Eremenko (1) , Luca Merucci (4) , Dario Stelitano (4) , Lorenzo Guerrieri (4) , Bernard Legras (10)

1 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques
2 Osservatorio Etneo di Catania
3 INGV - Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma
4 Osservatorio Nazionale Terremoti
5 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
6 TROPO - LATMOS
7 IMAA - Istituto di Metodologie per l'Analisi Ambientale
8 GSFC - NASA Goddard Space Flight Center
9 Dipartimento di Fisica "Ettore Pancini"
10 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)

During the extended activity of Mount Etna volcano in February-April 2021, three distinct paroxysmal events took place from 21 to 26 February, which were associated with a very uncommon transport of the injected upper-tropospheric plumes towards the north. Using a synergy of observations and modelling, we characterised the emissions and three-dimensional dispersion for these three plumes, we monitor their downwind distribution and optical properties, and we estimate their radiative impacts at selected locations. With a satellite-based source inversion, we estimate the emitted sulphur dioxide (SO2) mass at an integrated value of 55 kt and plumes injections at up to 12 km altitudes, which qualifies this series as an extreme event for Mount Etna. Then, we combine Lagrangian dispersion modelling, initialised with measured temporally-resolved SO2 emission fluxes and altitudes, with satellite observations to track the dispersion of the three individual plumes. The transport towards the north allowed the height-resolved downwind monitoring of the plumes at selected observatories in France, Italy and Israel, using LiDARs and photometric aerosol observations. Volcanic-specific aerosol optical depths in the visible spectral range ranging from about 0.004 to 0.03 and local daily average shortwave radiative forcing ranging from about -0.2 to -1.2 W/m2 (at the top of atmosphere) and from about -0.2 to -3.0 W/m2 (at the surface) are found. The composition (possible presence of ash), aerosol optical depth and radiative forcing of the plume has a large inter- and intra-plume variability and thus depend strongly on the position of the sampled section of the plumes.

Domains: Atmospheric and Oceanic Physics [physics.ao-ph]; Volcanology

Pasquale Sellitto, Giuseppe Salerno, Stefano Corradini, Irène Xueref-Remy, Aurélie Riandet, et al.. Volcanic Emissions, Plume Dispersion, and Downwind Radiative Impacts Following Mount Etna Series of Eruptions of February 21–26, 2021. Journal of Geophysical Research: Atmospheres, 2023, 128 (6), pp.e2021JD035974. ⟨10.1029/2021JD035974⟩. ⟨insu-03437407v2⟩