Satellite images of the volcanic eruptions
from Mount Etna in July 2001
by: J. Kerkmann (EUMETSAT)
View of Mount Etna on 26 July 2001 showing the lava stream approaching the
small town Nicolosi, Sicily (Photo: AP Photo /Pier Paolo Cito).
On early 17 July 2001, the latest in a series of violent eruptive episodes at the Southeast Crater of Mount Etna (3315 m) heralded what became a
very spectacular, complex and dangerous flank eruption, the first since the large 1991-1993 flank eruption. In the following days, ash frequently
rained down on Catania, forcing repeated closures of the international airport. On 22 and 23 July 2001, the flank eruption continued in full force
with a towering ash column rising from the explosive vent at about 2600 m elevation and drifting south-eastward, directly over Catania dropping
fine, dark grey ash onto everything.
Meteosat-7, visible channel, 23 July 2001 slots 16-32 (8:00-16:00 UTC)
The ash plume is well visible as a bright band (high reflectivity of ash particles as compared to the dark water surface) on the above series of
Meteosat-7 visible images. The wind direction was from the north-west (the typical wind direction for the season), but the wind direction slightly
varied during the day leading to an undulated structure of the plume. Furthermore, during the afternoon, the plume broadened a little bit
horizontally due to the onset of convection, which is also visible from the development of small cumulus clouds over Mount Etna. The ash
cloud, which totally obscured the sun over Catania, stayed compact over a long distance until it dissipated and became invisible over the island
of Crete (about 800 km distance).
The eruption of the Etna volcano and related atmospheric pollution was also closely monitored using the data from the GOME (Global Ozone
Monitoring Experiment ) instrument on the ERS-2 platform. GOME is a Nadir viewing across-track scanning spectrometer that measures the
radiance back-scattered from the atmosphere and the surface of the earth in the ultraviolet and visible range allowing the retrieval of
concentration of trace gases such as ozone (O3), sulphur dioxide (SO2) etc. The image below shows a 3-day composite of the SO2 concentration
derived from GOME data. The satellite data show a region south-east of Sicily where the atmosphere is polluted with a concentration of SO2 up
to 10 times higher than normal.
3-day composite (22-24 July 2001) of SO2 concentration retrieved from GOME data
(courtesy Deutsches Zentrum für Luft- und Raumfahrt (DLR) in Oberpfaffenhofen).The retrieval method
for trace gases from GOME-2 data is currently being developed at DLR in the framework of
the Satellite Application Facility (SAF) on Ozone Monitoring.
More satellite images from Mount Etna eruption in July 2001
ATSR (Along Track Scanning Radiometer) on ERS-2,
infrared and 11 micron channel, 24 July 2001, 9:52 GMT
(courtesy European Space Agency)
AVHRR (Advanced Very High Resolution Radiometer) on NOAA-15,
infrared channel, 23 July 2001, 04:24 UTC
(courtesy NOAA)
Mount Etna and the ash plume as seen from the MODIS (MODerate
resolution Imaging Spectrometer) instrument on Terra platform, date
unknown (courtesy DLR)
Digital image of Mount Etna recorded by one of the Expedition Two
crew members from the International Space Station (ISS) on 22 July
2001. Click here for full resolution image (1.7 MB).
SEAWIFS (Sea-viewing Wide Field-of-view Sensor) on SeaStar
spacecraft taken in the afternoon on 24 July 2001
(courtesy NASA Goddard Space Flight Center)
MISR (Multi-angle Imaging Spectro-Radiometer) on Terra platform,
25 July 2001, stereo anaglyph created from the instrument's 70-degree
and 46-degree forward views
(courtesy NASA Jet Propulsion Laboratory, MISR Team)