In this work, comparison results between data collected on the ground and by the Hyperspectral Thermal Emission Spectrometer (HyTES) acquired during the 2023 European airborne campaign are showed. NASA-Jet Propulsion Laboratory (JPL), European Space Agency (ESA), Italian Space Agency (ASI), National Centre for Space Studies (CNES), and various European universities and national research institutes collaboratively organized the campaign. Multiple test areas were designated in Italy, France, and Switzerland, with flights conducted from late May to mid-July. Here, we show the Italian volcanic areas, were specifically targeted for the HyTES flights. By this work, the authors aim to give an overview about the Italian Calibration and Validation (Cal/Val) sites, classified as thermally active sites, and to present preliminary results obtained in such area. The sites can be defined "thermally active" due to the presence of thermal anomalies at the surface related to volcanic activity ranging from 60°C to 1000°C. In addition, the same test sites have been selected in the THERESA (THErmal infRarEd SBG Algorithms) project, aimed to enhance algorithms for processing Thermal InfraRed data from the Surface Biology and Geology (SBG) – Thermal InfraRed (TIR) mission. During the lifetime of the project, THERESA will contribute to enhance the investigation of terrestrial phenomena by using both visible and thermal images.

World Heritage (WH) properties and heritage sites in general are exposed to the impacts of natural and man-triggered catastrophic events, which threaten their integrity and may compromise their value. The loss or deterioration of these outstanding properties has severely negative impacts on local and national communities, both because of their cultural importance, and because of their socio-economic value (https://whc.unesco.org/en/disaster-risk-reduction/). In the framework of the H2020-ARCH project a simplified approach was implemented for assessing and monitoring the subsidence hazards and the possible induced damages and short- and long-term impacts that these might cause on the buildings and other structures composing and characterising the WH sites. The InSAR data sets relating to the WH area of the Hamburg city were processed to evaluate the deformation velocity affecting each building, in order to project the Subsidence Related Intensity parameters in the short-and long-term, and thus estimate the expected damage levels through fragility curves. The results show a relatively stable situation in the area, however damage levels of a certain consistency are detectable for a long period due to the differential settlements. Furthermore, the results obtained allow us to evaluate the socio-economic impacts on the basis of some assumptions about potential losses.

The THERESA (THErmal infRarEd SBG Algorithms) project aims to enhance algorithms for processing Thermal InfraRed data from the SBG-TIR (Surface Biology and Geology – Thermal InfraRed) mission. Starting from state-of-the-art algorithms, THERESA takes in account the mission's technical features to develop algorithms exploiting diverse spectral channels. During the two years lifetime of the project, THERESA will contribute to enhance the investigation of terrestrial phenomena by using both visible and thermal images. The thematic areas that will benefit from SBG-TIR data range from the vegetation analysis to the volcanic eruptions and fires monitoring. Several parameters will be achieved such as the estimation of ash and SO2emissions from volcanoes, the surface temperature, the detection of hotspots as well as the FRP (Fire Radiative Power) in case of HTE’s (High Temperature Events). THERESA's innovation lies in algorithms advancements; the project offers a 360-degree support to the SBG-TIR mission.

This work aims to present the VULCAIN mission study to design and characterize a new CubeSat mission for Earth Observation dedicated to volcanoes. The project is supervised by the European Space Agency (ESA) and involves six Italian partners. The project involves the construction of two 12U nanosatellites flying in formation. Each satellite embarks two instruments onboard: a COTS VIS-NIR camera and a multispectral thermal camera with four channels in the 8-12 µm spectral range. The main scientific objectives are to measure the Land Surface Temperature (LST) and to combine VIS-TIR data to enhance the observation on volcanic areas by adding morphological analysis.

A quick analysis of gaseous content in volcanic plumes is possible by using hyperspectral remote sensing data. In the present work, an algorithm to calculate CO2columnar abundance in tropospheric volcanic plumes is applied to two volcanic test sites. The algorithm is based on the CIBR (Continuum Interpolated Band Ratio) remote sensing technique which exploits spectroscopy measurements by analyzing gases absorptions features in the SWIR (Short Wave InfraRed) spectral range. Specifically, PRISMA (PRecursore IperSpettrale della Missione Applicativa) hyperspectral satellite acquisitions are used for CO2retrieval purposes. The PRISMA space mission was launched by the ASI (Italian Space Agency) on March 22, 2019; the on board spectrometer is able to acquire images of the Earth in the VNIR ($0.4-1.0\ \ \mu \mathrm{m}$) and SWIR ($0.9-2.5\ \ \mu \mathrm{m}$) spectral ranges continuously, with a ground spatial resolution of 30 m. The inversion technique is applied to two Italian test sites: the Stromboli volcano and the Solfatara-Pisciarelli area (in the caldera of Campi Flegrei). The results show the capability of the method to detect and estimate strong CO2concentrations at a local spatial scale. While the satellite data provide a wide view of the emissions, in situ measurements are able to achieve accurate estimates of gases concentrations at very high spatial resolution. Acquisitions by a miniature multi-Gas analysis system, mounted on UAV (Unmanned Aerial Vehicle), are also considered. The multi-Gas instrument can measure H2O, CO2, H2S and SO2gases. Specifically, data of carbon dioxide concentrations acquired on the Solfatara-Pisciarelli test site are here presented.

The recent PRISMA (PRecursore IperSpettrale della Missione Applicativa) space mission, launched by the ASI (Italian Space Agency) on March 2019, brought in orbit a hyperspectral sensor (in the range$0.4-2.5 \mu\mathrm{m})$and a panchromatic camera with a spatial resolution of 30 and 5 meters, respectively. The PRISMA data are available for free (under license) and represent a unique orbiting source of hyperspectral data to investigate and analyze geophysical/geological phenomena. PRISMA works as the precursor of the next generation of ESA-SENTINEL satellites. In this work, a series of possible applications of PRISMA hyperspectral data are presented also considering data fusion with the panchromatic camera and the integration with other available satellite data as from Landsat and ASTER (Advanced Spaceborne Thermal Emission and Reflection).

Current EO satellite missions providing imagery in the VIS- TIR region at high spatial resolution offer the possibility to estimate a number of important parameters to monitor volcanic activities at worldwide level. Therefore, space missions contribute in understanding the ongoing phenomena to mitigate the volcanic risk when population and infrastructures are exposed. New hyperspectral and thermal missions which could provide images at high spatial and temporal resolution are under study in cooperation between Space Agencies (NASA, ASI, ESA etc.) and hopefully will improve the monitoring capabilities of active volcanoes in highly populated areas. In the present work we describe several results obtained in the last years by EO satellite missions for the volcanic risk. While the satellite data provide a wide description of scenes, in situ and proximal measurements are crucial to retrieve gas emissions and analyze surface characteristics at very high spatial resolution. Data acquired from drones (UAV) and thermal cameras in volcanic areas are presented and discussed. Moreover, this work shows the need of validation process for satellite products comparing with measurements collected during field campaigns.

Recently, the Italian Space Agency (ASI) and the Jet Propulsion Laboratory (JPL) have agreed to carry out a joint study for an Earth Observation scientific mission in the infrared spectral range (MWIR-LWIR). A mission of this type is considered of high priority by the NASA's “Decadal Survey” plan, as well as being one of the priorities of the future Sentinel of the Copernicus program. Furthermore, an MWIR-LWIR system with spatial resolutions better than 90 m (target 50 m) could represent a formidable integration of the observational capacity of the ASI PRISMA and SHALOM missions, as it would allow observing the entire wavelength range from Visible to thermal IR and consequently expanding the spectrum of scientific applications of the national satellite system. INGV in 2018-2019 in the frame of ASI contract has carried out a review of scientific and technical requirements for a new EO “Thermal Mission” which my support a large number of applications.

In June 2019 the ESA organized the airborne SurfSense campaign in the frame of the study of Copernicus candidate High Spatio-Temporal Resolution Land Surface Temperature Monitoring (LSTM) mission study. Parco delle Biancane was added as secondary target since the occurrence of a field campaign organized by INGV aimed to measure surface temperature using data acquired by different sensors at different spatial resolutions: Earth Observation (EO) data from the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS, [1]) and thermal images acquired by the FlyBit drone. In addition to these data, the airborne sensor Hyperspectral Thermal Emission Spectrometer (HyTES) was flown over the area. Our goal is to test the possibility to integrate data at different observation scales and to use the proximal measurements to better understand the thermal structure, the interaction of the environment in test areas and to validate the methodology for estimating the surface temperature by using EO data.

In the frame of the Italian Space Agency (ASI) Hyperspectral Space Mission PRISMA, the Istituto Nazionale di Geofisica e Vulcanologia coordinates the scientific project ASI-AGI aimed to develop specific algorithms and products for geophysical applications. Data validation and calibration activities have been focused on active volcanic areas and three test sites have been selected in Sicily, Italy. In the period 23-27 June 2012 the project team has organized an hyperspectral airborne and field measurements campaign over Mt. Etna, Paternò area and Ciclopi Islands investigating various surface targets using different instruments. The airborne and ground campaign have been planned during satellites passes of Hyperion and ASTER. The whole data set acquired during this campaign allowed the airborne data calibration and provide a suitable data set to simulate PRISMA data and to test the developed algorithms in the framework of the project.

Volcanic plumes represent a visible indicator of volcanic activity. They vary in space and time, strongly influenced by the quiescent or eruptive status of the volcano. Different volcanic activities, such as volcanic clouds and plumes, inject into the atmosphere gases and aerosol at different latitudes, altitudes and with different times of residence. Released by the magma, plumes are a turbulent mixture of gases, solid particles and liquid droplets, emitted at high temperature continuously from summit craters, fumarolic fields or during eruptive episodes. Mt. Etna, in Sicily (Italy), is one of the world's most frequent emitters of volcanic plumes. It show a permanent degassing plumes periodically interrupted by copious tephra emission and fallout that damage the inhabited and cultivated areas and created serious hazards to air traffic, as volcanic clouds can spread thousand of km in the central Mediterranean area. Recurrent closures of the Catania International airport have often been necessary, causing great losses to the local economy (Andronico et al 2009). For these reasons Mt. Etna is continually monitored and recent a new approach has been adapted integrating ground network data with the analysis of space data. In order to extract geophysical parameters related to volcano status software modules has been developed divided by early warning phase, crisis phase and post- crisis phase. Modules using already developed remote sensing techniques in the VIS and IR wavelength range. Here we present two modules for the Mt. Etna volcanic plume analysis using ASTER on TERRA and HYPERION on EO-1 data. This study is carried out within the SRV project, funded by the Italian Space Agency (ASI).

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER ) has operated since 19 December 1999 from NASA's Terra Earth-orbiting, sun synchronous satellite. Emissivity and temperature standard products are based on the TES algorithms and required periodical validation campaign. In the frame of the EC project PREVIEW (http://www.preview-risk.com/) a field campaign on Volcano Teide was carried on, from the 16th to 24th of September 2007, to validate and to integrate the satellite derived products services.

The ASI-SRV (Sistema Rischio Vulcanico) project is devoted to the development of an integrated system based on EO and Non EO data to respond to specific needs of the Italian Civil Protection Department (DPC). ASI-SRV provides the capability to import many different EO and Non EO data into the system, it maintains a repository where the acquired data have to be stored and generates selected products which will be functional to the different volcanic activity phases. The processing modules for Radar and EO Optical sensors data allow to estimate a number of parameters which include: surface thermal proprieties, gas, aerosol and ash emissions and to characterize the volcanic products in terms of composition and geometry, surface deformations in terms of displacements and velocity. All the generated products are related to Italian actives volcanoes and three test sites have been chosen to demonstrate the capability of this integrated system: Vesuvio, Campi Flegrei (Campania region) and Etna (Sicilia region). In this paper the first results obtained by means of modules developed within the ASI-SRV project and dedicated to the processing of EO historical series are presented.

During July 2003 a new airborne system named FASA was tested on Italian volcanoes. FASA that stands for Fire Airborne Spectral Analyzer, is a system devoted to high temperature events study. The payload on the airborne consisted of an imager (ABAS) and an high resolution Michelson interferometer with rotating retroreflector MIROR operating in the nominal infrared 2.5-18 /spl mu/m range. MIROR was developed by DLR and adapted for airborne measurement by INGV that provided an opto-mechanical interface and a calibration unit software control. By using three black body sources at different temperature is possible to compute instrumental transfer function and reduce instrumental noise. In this study we describe pre-flight test and the in flight calibration results. Preliminary results of radiance spectra on the Mount Etna surface and emissivity are shown.

This from 17 July until 26 July, 2003, a field campaign on Mount Etna and on the island of Vulcano, was carried out jointly to airborne campaign (FASA). FASA (Fire Airborne Spectral Analyze) is the airborne main instrument composed by an imager and a Fourier Transform Spectrometer in the 3.3-13 /spl mu/m IR range. The field campaign was aimed to the validation and calibration of remote-sensed data. A series of target sites, representative of the present-day volcanoes surface and recognizable from a great distance, have been geologically and spectrally characterized. The spatial emissivity of the surface materials has been measured by means of a portable Fourier transform infrared spectroradiometer dedicated to the field measurement of spectral radiance from Earth 's surface and atmosphere. This spectrometer operates at wavelengths ranging from 2 to 16 /spl mu/m with a spectral resolution of 2 cm/sup -1/. We will show the methods and the emissivity measured for a representative samples of target sites. Airborne and field spectra were compared to laboratory spectra of selected samples.

In the present study a remote sensing differential absorption technique, already developed to calculate the atmospheric water vapour abundance, has been adapted to calculate water vapour columnar abundance in tropospheric volcanic plume. Water vapour is the most abundant gas of a volcanic plume released into the atmosphere from an active volcanic system. The technique is based on the correlation between the dip in the spectral curve measured by the spectrometer were water vapour absorptions bands are presents, and the precipitable water content in the column. Airborne and satellite remote sensing images in the infrared wavelength range were used. The technique has been applied to data acquired over two different degassing volcanoes. The Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) acquired data over the Hawaiian Pu'u'O'o Vent cone of the Kilauea volcano on April 2000. The Hyperion sensor on EO-1 satellite has been requested to acquire data on July 2003, during a ground-based measurements campaign on Mt. Etna (Italy). The result is the spatial distribution of water vapour abundance of the Mt. Etna and of the Pu'u'O'o Vent volcanic plumes. A comparison between the two results has been done, showing the differences in the volcanic activity. The algorithm produces reliable results compared to the ground based measurements in the plume area acquired during a measurements campaign over Mt. Etna.

The algorithm described in this paper approaches the atmospheric correction of hyperspectral data as a spectral unmixing problem, minimizing the need of a priori information on atmospheric conditions and maximizing the advantage of hyperspectral data. The proposed method is foreseen to be used for the processing of the HypSEO mission data, an Italian Space Agency future mission aimed to the demonstration of the spaceborne hyperspectral sensor technology and data exploitation.