Remote sensing scientists have developed an innovative method that combines atmospheric data with Earth observation imagery to probe the behaviour of an Italian volcano that is known for its frequent and violent eruptions.
The analysis – which focused on the Stromboli volcano off the north coast of Sicily – could help volcanologists characterise the risks of eruptions, supporting mitigation efforts in local communities.
The project – completed at the Italian Space Agency (ASI) – drew on data delivered by Sentinel-2 and Sentinel-5P of the European Union’s Copernicus Programme.
Copernicus Sentinel-2 and Copernicus Sentinel-5p
Stromboli has been erupting intermittently since records began. Despite its relatively small size compared to other volcanoes such as Mount Etna, these explosions can be violent and destructive, posing a significant and continuous threat to local inhabitants and tourists.
The term ‘Strombolian eruption’ is now used to describe similar blasts around the world.
To support mitigation efforts, scientists are working to increase their understanding of these eruptions.
The venting of sulphur dioxide from Strombolian volcanoes is associated with the presence of magma near the surface. As a result, monitoring this gas can deliver insight into the style and intensity of eruptions.
However, many space-borne sensors lack the sensitivity to detect the small-scale changes in sulphur dioxide concentrations that are linked to Strombolian activity.
Launched in 2017, Copernicus Sentinel-5P carries a TROPOspheric Monitoring Instrument (TROPOMI) that delivers high-resolution information on key atmospheric constituents.
The analysis drew on sulphur dioxide vertical column density data collected by TROPOMI between May 2018 to May 2021, a period in which there were several sequences of eruptions with varying levels of intensity.
Copernicus Sentinel-2 captures Stromboli volcano
As part of the project, researchers developed a method that was used to transform these data into a time-series that detailed sulphur dioxide abundances over Stromboli. Using this, they picked out instances where levels of the gas were particularly high.
But, in order to correctly interpret these data, contextual information about the activity of the volcano was required.
To obtain this, the scientists inspected images collected by the multi-spectral instrument carried by Copernicus Sentinel-2 to search for the tell-tale signs of volcanic activity, such as lava pouring from Stromboli’s crater.
By using this approach, they were able to associate periods of high emissions with known instances of volcanic activity.
To validate these findings, the researchers used measurements collected from ground sensor networks on Stromboli, which are reported in official bulletins issued regularly by volcanological observatory teams.
Using Copernicus data to track volcanic activity
By comparing the time series developed with TROPOMI data with in-situ measurements, they were able to identify interferences from other sources of sulphur dioxide, such as other volcanoes like Mount Etna or anthropogenic activities.
In the future, the research team expects that their analysis method will be applied by volcanologists to investigate and monitor other Strombolian volcanoes across the world.
Alessandra Cofano, remote sensing scientist and key contributor to the ASI project, says, “The method we developed as part of this research activity adheres to the holistic concept of multi-band and multi-mission observations that is behind the whole Copernicus Earth observation programme. We look forward to exploring the possibility of using this approach to study other Strombolian volcanoes around the globe.”
About the Copernicus Sentinels
The Copernicus Sentinels are a fleet of dedicated EU-owned satellites, designed to deliver the wealth of data and imagery that are central to the European Union's Copernicus environmental programme.
The European Commission leads and coordinates this programme, to improve the management of the environment, safeguarding lives every day. ESA is in charge of the space component, responsible for developing the family of Copernicus Sentinel satellites on behalf of the European Union and ensuring the flow of data for the Copernicus services, while the operations of the Copernicus Sentinels have been entrusted to ESA and EUMETSAT.
Did you know that?
Earth observation data from the Copernicus Sentinel satellites are fed into the Copernicus Services. First launched in 2012 with the Land Monitoring and Emergency Management services, these services provide free and open support, in six different thematic areas.
The Copernicus Atmosphere Monitoring Service (CAMS) provides continuous data and information on atmospheric composition. It supports many applications in a variety of domains including health, environmental monitoring, renewable energies, meteorology and climatology.
The Copernicus Land Monitoring Service (CLMS) provides geographical information on land cover and its changes, land use, vegetation state, water cycle and Earth's surface energy variables, to a broad range of users in Europe and across the World in the field of environmental terrestrial applications. It supports applications in a variety of domains such as spatial and urban planning, forest management, water management, agriculture and food security, nature conservation and restoration, rural development, ecosystem accounting and mitigation/adaptation to climate change.
References
Cofano, A.; Cigna, F.; Santamaria Amato, L.; Siciliani de Cumis, M.; Tapete, D. Exploiting Sentinel-5P TROPOMI and Ground Sensor Data for the Detection of Volcanic SO2 Plumes and Activity in 2018–2021 at Stromboli, Italy., Sensors 2021, 21, 6991.