Synergistic use of Lagrangian dispersion and radiative transfer modelling with satellite and surface remote sensing measurements for the investigation of volcanic plumes: the Mount Etna eruption of 25–27 October 2013

Abstract

Abstract. In this paper we combine SO 2 and ash plume dispersion modelling with satellite and surface remote sensing observations to study the regional influence of a relatively weak volcanic eruption from Mount Etna on the optical and micro-physical properties of Mediterranean aerosols. We analyse the Mount Etna eruption episode of 25-27 October 2013. The evolution of the plume along the trajectory is investigated by means of the FLEXible PARTicle Lagrangian dispersion (FLEXPART) model. The satellite data set includes true colour images, retrieved values of volcanic SO 2 and ash, estimates of SO 2 and ash emission rates derived from MODIS (MODerate resolution Imaging Spectroradiometer) observations and estimates of cloud top pressure from SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Surface remote sensing measurements of aerosol and SO 2 made at the ENEA Station for Climate Observations (35.52 • N, 12.63 • E; 50 m a.s.l.) on the island of Lampedusa are used in the analysis. The combination of these different data sets suggests that SO 2 and ash, despite the initial injection at about 7.0 km altitude, reached altitudes around 10-12 km and influenced the column average aerosol particle size distribution at a distance of more than 350 km downwind. This study indicates that even a relatively weak volcanic eruption may produce an observable effect on the aerosol properties at the regional scale. The impact of secondary sulfate particles on the aerosol size distribution at Lampedusa is discussed and estimates of the clear-sky direct aerosol radiative forcing are derived. Daily shortwave radiative forcing efficiencies, i.e. radiative forcing per unit AOD (aerosol optical depth), are calculated with the LibRadtran model. They are estimated between −39 and −48 W m −2 AOD −1 at the top of the atmosphere and between −66 and −49 W m −2 AOD −1 at the surface, with the variability in the estimates mainly depending on the aerosol single scattering albedo. These results suggest that sulfate particles played a large role in the transported plume composition and radiative forcing, while the contribution by ash particles was small in the volcanic plume arriving at Lampedusa during this event.

Aerosol Optical Properties of Pacaya Volcano Plume Measured with a Portable Sun-Photometer

“…Volcanic emissions have important impacts on the atmospheric composition (e.g., [1,2]), cloud distribution (e.g., [3]) and regional (e.g., [4]) to global climate (e.g., [5]). The direct climate forcing of volcanic plumes critically depends on the optical and micro-physical properties of the volcanic aerosols, that in turn depend on the evolution processes of the effluents in the atmosphere [6].…”

Retrieval and intercomparison of volcanic SO2 injection height and eruption time from satellite maps and ground-based observations

“…Clarisse et al, (2014) introduces and validates a new method for the retrieval of SO 2 plume height from IASI measurements using the Nabro 2011 eruption as a case study. Hyperspectral infrared observations (Carboni et al, 2012(Carboni et al, , 2015 and inverse modelling procedures (Moxnes et al, 2014;Boichu et al, 2013Boichu et al, , 2015 have also shown promising results.…”

“…Back-trajectory analysis of volcanic plumes has been performed by Hughes, et al (2012) and Sellitto, et al (2015) with the aim of studying the transport paths of SO 2 clouds produced from …”

The EtnaPlumeLab (EPL) research cluster: advance the understanding of Mt. Etna plume, from source characterisation to downwind impact

“…While the project is mostly target to the Central-Eastern Mediterranean, where up to 80% of the Etnean plume disperses [Sellitto et al, 2017], the less downwindventilated Central-Southern Mediterranean region is also explored [Sellitto et al, 2016].…”

“…Etna, thus exerting a significant, episodic radiative forcing [Sellitto et al, 2016], which is critically dependent from chemical/micro-physical processes in atmosphere [Sellitto and Briole, 2015]. The radiative impact is studied with both radiative transfer modelling and satellite observations of radiative fluxes.…”