Space techniques based on GPS and SAR interferometry allow measuring millimetric ground deformati... more Space techniques based on GPS and SAR interferometry allow measuring millimetric ground deformations. Achieving such accuracy means removing atmospheric anomalies that frequently affect volcanic areas by modeling the tropospheric delays. Due to the prominent orography and the high spatial and temporal variability of weather conditions, the active volcano Mt. Etna (Italy) is particularly suitable to carry out research aimed at estimating and filtering atmospheric effects on GPS and DInSAR ground deformation measurements. The aim of this work is to improve the accuracy of the ground deformation measurements by modeling the tropospheric delays at Mt. Etna volcano. To this end, data from the monitoring network of 29 GPS permanent stations and MODIS multispectral satellite data series are used to reproduce the tropospheric delays affecting interferograms. A tomography algorithm has been developed to reproduce the wet refractivity field over Mt. Etna in 3D, starting from the slant tropospheric delays calculated by GPS in all the stations of the network. The developed algorithm has been tested on a synthetic atmospheric anomaly. The test confirms the capability of the software to faithfully reconstruct the simulated anomaly. With the aim of applying this algorithm to real cases, we introduce the water vapor content measured by the MODIS instrument on board Terra and Aqua satellites. The use of such data, although limited by cloud cover, provides a twofold benefit: it improves the tomographic resolution and adds feedback for the GPS wet delay measurements. A cross-comparison between GPS and MODIS water vapor measurements for the first time shows a fair agreement between those indirect measurements on an entire year of data (2015). The tomography algorithm was applied on selected real cases to correct the Sentinel-1 DInSAR interferograms acquired over Mt. Etna during 2015. Indeed, the corrected interferograms show that the differential path delay reaches 0.1 m (i.e. 3 C-band fringes) in ground deformation, demonstrating how the atmospheric anomaly affects precision and reliability of DInSAR space-based techniques. The real cases show that the tomography is often able to capture the atmospheric effect at the large scale and correct interferograms, although in limited areas. Furthermore, the introduction of MODIS data significantly improves by ∼80% voxel resolution at the critical layer (1,000 m). Further improvements will be suitable for monitoring active volcanoes worldwide.
The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigat... more The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Avi ation Hazards, was introduced after the eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 to facilitate the development of an optimal EndtoEnd System for Volcanic Ash Plume Monitoring and Predic tion. The Eyjafjallajökull plume drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people. The limitations in volcanic plume monitoring and prediction capabilities gave birth to this observational system which is based on comprehensive satellitederived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and groundbased measurements. Intercomparison of the volcanic total SO2 column and plume height observed by GOME2/MetopA and IASI/MetopA are shown before, during and after the Eyjaf jallajökul...
The volcanic areas affected by pyroclastic deposits and significant hillslopes can be considered ... more The volcanic areas affected by pyroclastic deposits and significant hillslopes can be considered zone with high proneness for triggering volcaniclastic debris flows. In fact, in presence of heavy and/or persistent rainfall, loose pyroclastic covers can be remobilized and generate volcaniclastic flows causing disastrous effects. The most important volcanoclastic debris flow in the Campania Region (Italy) has been the Sarno-Quindici event occurred on May 5-6, 1998 that caused the death of more than 150 people and relevant damages to villages at the foot of the Apennine Mountains in the circumvesuvian area. In order to improve the volcaniclastic flow hazard zonation in the area surrounding the Vesuvius volcano, we propose a methodological approach based on remote sensing analyses combined with morphometric study derived from a Digital Elevation Model having a spatial resolution of 10 meters to identify the drainage basins potentially more prone to generate volcaniclastic flows. The sat...
Envisat MERIS and AATSR data have been acquired in the framework of the Eurorisk-Preview project.... more Envisat MERIS and AATSR data have been acquired in the framework of the Eurorisk-Preview project. The project addresses European civil protections and proposes to develop, at the European scale, new information services to support the risk management. In Italy one of the most important natural risks is due to the presence of volcanoes. Mt. Etna in Sicily, displays persistent activity, periodically interrupted by eruptions, which emit volcanic aerosol and ash to different altitudes in troposphere affecting the central Mediterranean area. In order to test the use of MERIS and AATSR data to derive emitted particles parameters as optical depth, effective radius and the ash mass of particles, the already developed remote sensing techniques has been adapted. MERIS and AATSR data acquired during the Mt. Etna 2002-2003 volcanic eruption has been chosen. The use of VIS and TIR bands of the two sensor demonstrates the potential to derive useful information on plume particles and to monitor th...
Within the framework of the European MVRRS project (Mitigation of Volcanic Risk by Remote Sensing... more Within the framework of the European MVRRS project (Mitigation of Volcanic Risk by Remote Sensing Techniques), in June 1997 an airborne campaign was organised on Mt. Etna to study different characteristics of the volcanic plume emitted by the summit craters in ...
Located at the bottom of the Gulf of Guinea, Cameroon is exposed to a large variety of natural ha... more Located at the bottom of the Gulf of Guinea, Cameroon is exposed to a large variety of natural hazards, including volcanism. Most of the hazard are concentrated around the active volcano Mt. Cameroon which combines effusive and explosive types of activity. The threatened stakes are numerous and different exposed: people, settlements, industrial plantations, petrol refinery and many other factories and infrastructures. Until 2005, no risk management plans has been available. In 2006, the French Embassy in Cameroon, within the framework of a financial convention between Cameroon and France, put in place the GRINP (Management of Natural Risks and Civil Protection) project whose objective was to reinforce the capacity of Cameroon's civil protection department and thus, contribute to the improvement of the security of the population faced with catastrophes. The objective was to realize a Risk Prevention Plan at a local council scale, and taking into consideration the specific natural risks of each zone. The general objective of the RPP was to clearly draw land use maps for risks zones, showing the overlay of stakes with risk of different intensities. In 2008 European Commission funded the Mia-Vita project (Mitigating and Assessing Volcanic Impacts on Terrain and human Activities). The aim of the project is to improve the crisis management capabilities based on monitoring and early warning systems and secure communications; reduction of people's vulnerability and development of recovering capabilities after an event occurs for both local communities and ecological systems. Keyword: natural hazards, Mt. Cameroon, vulnerability, risk prevention plan
High-resolution digital topography is essential for land management and
planning in any type of t... more High-resolution digital topography is essential for land management and planning in any type of territory as well as the reproduction of the Earth surface in a geocoded digital format that allows several Digital Earth applications. In a volcanic environment, Digital Elevation Models are a valid reference for multi-temporal analyses aimed to observe frequent changes of a volcano edifice and for the relative detailed morphological and structural analyses. For the first time, a DTM (Digital Terrain Model) and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano (Italy) derived from the same airborne Light Detection and Ranging (LiDAR) are here presented. More than 250 million 3D LiDAR points have been processed to distinguish ground elements from natural and anthropic features. The end product is the highly accurate representation of Mt. Etna landscape (DSM) and ground topography (DTM) dated 2005. Both models have a high spatial resolution of 2 m and cover an area of 620 km2. The DTM has been validated by GPS ground control points. The vertical accuracy has been evaluated, resulting in a root-mean-square-error of ± 0.24 m. The DTM is available as electronic supplement and represents a valid support for various scientific studies.
Mt. Etna, in Sicily (Italy), is one of the world's most frequent emitters of volcanic plumes.... more Mt. Etna, in Sicily (Italy), is one of the world's most frequent emitters of volcanic plumes. During the last ten years, Etna has produced copious tephra emission and fallout that have damaged the inhabited and cultivated areas on its slopes and created serious hazards to air traffic. Recurrent closures of the Catania International airport have often been necessary, causing great losses to the local economy. Recently, frequent episodes of ash emission, lasting from a few hours to days, occurred from July to December 2006, necessitating a look at additional monitoring techniques, such as remote sensing. The combination of a ground monitoring system with polar satellite data represents a novel approach to monitor Etna's eruptive activity, and makes Etna one of the few volcanoes for which this surveillance combination is routinely available.
Space techniques based on GPS and SAR interferometry allow measuring millimetric ground deformati... more Space techniques based on GPS and SAR interferometry allow measuring millimetric ground deformations. Achieving such accuracy means removing atmospheric anomalies that frequently affect volcanic areas by modeling the tropospheric delays. Due to the prominent orography and the high spatial and temporal variability of weather conditions, the active volcano Mt. Etna (Italy) is particularly suitable to carry out research aimed at estimating and filtering atmospheric effects on GPS and DInSAR ground deformation measurements. The aim of this work is to improve the accuracy of the ground deformation measurements by modeling the tropospheric delays at Mt. Etna volcano. To this end, data from the monitoring network of 29 GPS permanent stations and MODIS multispectral satellite data series are used to reproduce the tropospheric delays affecting interferograms. A tomography algorithm has been developed to reproduce the wet refractivity field over Mt. Etna in 3D, starting from the slant tropospheric delays calculated by GPS in all the stations of the network. The developed algorithm has been tested on a synthetic atmospheric anomaly. The test confirms the capability of the software to faithfully reconstruct the simulated anomaly. With the aim of applying this algorithm to real cases, we introduce the water vapor content measured by the MODIS instrument on board Terra and Aqua satellites. The use of such data, although limited by cloud cover, provides a twofold benefit: it improves the tomographic resolution and adds feedback for the GPS wet delay measurements. A cross-comparison between GPS and MODIS water vapor measurements for the first time shows a fair agreement between those indirect measurements on an entire year of data (2015). The tomography algorithm was applied on selected real cases to correct the Sentinel-1 DInSAR interferograms acquired over Mt. Etna during 2015. Indeed, the corrected interferograms show that the differential path delay reaches 0.1 m (i.e. 3 C-band fringes) in ground deformation, demonstrating how the atmospheric anomaly affects precision and reliability of DInSAR space-based techniques. The real cases show that the tomography is often able to capture the atmospheric effect at the large scale and correct interferograms, although in limited areas. Furthermore, the introduction of MODIS data significantly improves by ∼80% voxel resolution at the critical layer (1,000 m). Further improvements will be suitable for monitoring active volcanoes worldwide.
The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigat... more The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Avi ation Hazards, was introduced after the eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 to facilitate the development of an optimal EndtoEnd System for Volcanic Ash Plume Monitoring and Predic tion. The Eyjafjallajökull plume drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people. The limitations in volcanic plume monitoring and prediction capabilities gave birth to this observational system which is based on comprehensive satellitederived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and groundbased measurements. Intercomparison of the volcanic total SO2 column and plume height observed by GOME2/MetopA and IASI/MetopA are shown before, during and after the Eyjaf jallajökul...
The volcanic areas affected by pyroclastic deposits and significant hillslopes can be considered ... more The volcanic areas affected by pyroclastic deposits and significant hillslopes can be considered zone with high proneness for triggering volcaniclastic debris flows. In fact, in presence of heavy and/or persistent rainfall, loose pyroclastic covers can be remobilized and generate volcaniclastic flows causing disastrous effects. The most important volcanoclastic debris flow in the Campania Region (Italy) has been the Sarno-Quindici event occurred on May 5-6, 1998 that caused the death of more than 150 people and relevant damages to villages at the foot of the Apennine Mountains in the circumvesuvian area. In order to improve the volcaniclastic flow hazard zonation in the area surrounding the Vesuvius volcano, we propose a methodological approach based on remote sensing analyses combined with morphometric study derived from a Digital Elevation Model having a spatial resolution of 10 meters to identify the drainage basins potentially more prone to generate volcaniclastic flows. The sat...
Envisat MERIS and AATSR data have been acquired in the framework of the Eurorisk-Preview project.... more Envisat MERIS and AATSR data have been acquired in the framework of the Eurorisk-Preview project. The project addresses European civil protections and proposes to develop, at the European scale, new information services to support the risk management. In Italy one of the most important natural risks is due to the presence of volcanoes. Mt. Etna in Sicily, displays persistent activity, periodically interrupted by eruptions, which emit volcanic aerosol and ash to different altitudes in troposphere affecting the central Mediterranean area. In order to test the use of MERIS and AATSR data to derive emitted particles parameters as optical depth, effective radius and the ash mass of particles, the already developed remote sensing techniques has been adapted. MERIS and AATSR data acquired during the Mt. Etna 2002-2003 volcanic eruption has been chosen. The use of VIS and TIR bands of the two sensor demonstrates the potential to derive useful information on plume particles and to monitor th...
Within the framework of the European MVRRS project (Mitigation of Volcanic Risk by Remote Sensing... more Within the framework of the European MVRRS project (Mitigation of Volcanic Risk by Remote Sensing Techniques), in June 1997 an airborne campaign was organised on Mt. Etna to study different characteristics of the volcanic plume emitted by the summit craters in ...
Located at the bottom of the Gulf of Guinea, Cameroon is exposed to a large variety of natural ha... more Located at the bottom of the Gulf of Guinea, Cameroon is exposed to a large variety of natural hazards, including volcanism. Most of the hazard are concentrated around the active volcano Mt. Cameroon which combines effusive and explosive types of activity. The threatened stakes are numerous and different exposed: people, settlements, industrial plantations, petrol refinery and many other factories and infrastructures. Until 2005, no risk management plans has been available. In 2006, the French Embassy in Cameroon, within the framework of a financial convention between Cameroon and France, put in place the GRINP (Management of Natural Risks and Civil Protection) project whose objective was to reinforce the capacity of Cameroon's civil protection department and thus, contribute to the improvement of the security of the population faced with catastrophes. The objective was to realize a Risk Prevention Plan at a local council scale, and taking into consideration the specific natural risks of each zone. The general objective of the RPP was to clearly draw land use maps for risks zones, showing the overlay of stakes with risk of different intensities. In 2008 European Commission funded the Mia-Vita project (Mitigating and Assessing Volcanic Impacts on Terrain and human Activities). The aim of the project is to improve the crisis management capabilities based on monitoring and early warning systems and secure communications; reduction of people's vulnerability and development of recovering capabilities after an event occurs for both local communities and ecological systems. Keyword: natural hazards, Mt. Cameroon, vulnerability, risk prevention plan
High-resolution digital topography is essential for land management and
planning in any type of t... more High-resolution digital topography is essential for land management and planning in any type of territory as well as the reproduction of the Earth surface in a geocoded digital format that allows several Digital Earth applications. In a volcanic environment, Digital Elevation Models are a valid reference for multi-temporal analyses aimed to observe frequent changes of a volcano edifice and for the relative detailed morphological and structural analyses. For the first time, a DTM (Digital Terrain Model) and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano (Italy) derived from the same airborne Light Detection and Ranging (LiDAR) are here presented. More than 250 million 3D LiDAR points have been processed to distinguish ground elements from natural and anthropic features. The end product is the highly accurate representation of Mt. Etna landscape (DSM) and ground topography (DTM) dated 2005. Both models have a high spatial resolution of 2 m and cover an area of 620 km2. The DTM has been validated by GPS ground control points. The vertical accuracy has been evaluated, resulting in a root-mean-square-error of ± 0.24 m. The DTM is available as electronic supplement and represents a valid support for various scientific studies.
Mt. Etna, in Sicily (Italy), is one of the world's most frequent emitters of volcanic plumes.... more Mt. Etna, in Sicily (Italy), is one of the world's most frequent emitters of volcanic plumes. During the last ten years, Etna has produced copious tephra emission and fallout that have damaged the inhabited and cultivated areas on its slopes and created serious hazards to air traffic. Recurrent closures of the Catania International airport have often been necessary, causing great losses to the local economy. Recently, frequent episodes of ash emission, lasting from a few hours to days, occurred from July to December 2006, necessitating a look at additional monitoring techniques, such as remote sensing. The combination of a ground monitoring system with polar satellite data represents a novel approach to monitor Etna's eruptive activity, and makes Etna one of the few volcanoes for which this surveillance combination is routinely available.
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Papers by Claudia Spinetti
planning in any type of territory as well as the reproduction of the Earth
surface in a geocoded digital format that allows several Digital Earth
applications. In a volcanic environment, Digital Elevation Models are a
valid reference for multi-temporal analyses aimed to observe frequent
changes of a volcano edifice and for the relative detailed morphological
and structural analyses. For the first time, a DTM (Digital Terrain Model)
and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano
(Italy) derived from the same airborne Light Detection and Ranging
(LiDAR) are here presented. More than 250 million 3D LiDAR points have
been processed to distinguish ground elements from natural and
anthropic features. The end product is the highly accurate
representation of Mt. Etna landscape (DSM) and ground topography
(DTM) dated 2005. Both models have a high spatial resolution of 2 m
and cover an area of 620 km2. The DTM has been validated by GPS
ground control points. The vertical accuracy has been evaluated,
resulting in a root-mean-square-error of ± 0.24 m. The DTM is available
as electronic supplement and represents a valid support for various
scientific studies.
planning in any type of territory as well as the reproduction of the Earth
surface in a geocoded digital format that allows several Digital Earth
applications. In a volcanic environment, Digital Elevation Models are a
valid reference for multi-temporal analyses aimed to observe frequent
changes of a volcano edifice and for the relative detailed morphological
and structural analyses. For the first time, a DTM (Digital Terrain Model)
and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano
(Italy) derived from the same airborne Light Detection and Ranging
(LiDAR) are here presented. More than 250 million 3D LiDAR points have
been processed to distinguish ground elements from natural and
anthropic features. The end product is the highly accurate
representation of Mt. Etna landscape (DSM) and ground topography
(DTM) dated 2005. Both models have a high spatial resolution of 2 m
and cover an area of 620 km2. The DTM has been validated by GPS
ground control points. The vertical accuracy has been evaluated,
resulting in a root-mean-square-error of ± 0.24 m. The DTM is available
as electronic supplement and represents a valid support for various
scientific studies.