Publication Date:
2018-03-20
Description:
In this paper we combine SO2 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 SO2 and ash, estimates of SO2 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 SO2 made at the ENEA Station for Climate
Observations (35.52 N, 12.63 E; 50ma.s.l.) on the island
of Lampedusa are used in the analysis. The combination
of these different data sets suggests that SO2 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
48Wm^-2 AOD^ -1 at the top of the atmosphere and between
66 and 49Wm^-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.
Description:
Published
Description:
6841–6861
Description:
5V. Dinamica dei processi eruttivi e post-eruttivi
Description:
6V. Pericolosità vulcanica e contributi alla stima del rischio
Description:
2SR. VULCANI - Servizi e ricerca per la Società
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink