ALBERT

Description: The purpose of this study is to analyze the surface temperature and the distribution of thermal signatures on Tuscany’s geothermal districts using data obtained through three separate surveys via satellite and an unmanned aerial vehicle (UAV). The analysis considers the highest available spatial resolution ranging from hundreds of meters per pixel of the satellite thermal images and the tenths/hundreds of centimeters per pixel of the thermal images acquired by the UAV. The surface temperature maps obtained by satellite data acquired at suitable spatial resolution and the thermal measurements obtained by the thermal camera installed on the UAV were orthorectified and geocoded. This allowed, for example, following the evolution of thermal anomalies, which may represent a modification of the current state of the geothermal field and a possible hazard for both the population and industrial assets. Here, we show the results obtained in three field campaigns during which the simultaneous acquisition of Landsat 8 satellite and UAV (FlyBit octocopter, IDS, Rome, Italy) thermal data were analyzed. By removing the atmosphere contribution from Landsat 8 data, we have produced three surface temperature maps that are compared with the ground field measurements and the surface temperature maps elaborated by FLIR VUE PRO-R on the UAV.

Description: Land Surface Temperature (LST) from satellite data is a key component in many aspects of environmental research. In volcanic areas, LST is used to detect ground thermal anomalies providing a supplementary tool to monitor the activity status of a particular volcano. In this work, we describe a procedure aimed at identifying spatial thermal anomalies in thermal infrared (TIR) satellite frames which are corrected for the seasonal influence by using TIR images from ground stations. The procedure was applied to the volcanic area of Campi Flegrei (Italy) using TIR ASTER and Landsat 8 satellite imagery and TIR ground images acquired from the Thermal Infrared volcanic surveillance Network (TIRNet) (INGV, Osservatorio Vesuviano). The continuous TIRNet time-series images were processed to evaluate the seasonal component which was used to correct the surface temperatures estimated by the satellite’s discrete data. The results showed a good correspondence between de-seasoned time series of surface ground temperatures and satellite temperatures. The seasonal correction of satellite surface temperatures allows monitoring of the surface thermal field to be extended to all the satellite frames, covering a wide portion of Campi Flegrei volcanic area.

Description: The Campi Flegrei volcanic area (Italy) is part of the Neapolitan volcanic district, a high volcanic risk area where population and human activities are exposed. It is monitored by INGV multi-platform surveillance networks systems. In this work we performed a comparison of the surface temperature in volcanic areas between satellite imagery in the Thermal Infrared (TIR) bandwidth and infrared thermal scenes acquired by ground cameras network (TIRNet). TIRS on LANDSAT and ASTER on NASA-TERRA provide thermal IR channels to monitor the evolution of the surface temperatures on Campi Flegrei area. The spatial resolution of the TIR LANDSAT8 data is 100 m and ASTER resolution is 90 m. Temporal resolution is 16 days for both satellites. TIRNet network has been developed by INGV-Osservatorio Vesuviano for long-term volcanic surveillance of Campi Flegrei caldera through the acquisition of thermal infrared images. The system is currently composed of 5 permanent stations equipped with FLIR A645SC cameras using a 640x480 resolution IR sensor. Acquisitions and data transmission are managed remotely through technology specially developed at INGV laboratories in Naples. To improve the systematic use of satellite data in the monitoring procedures of Volcanic Observatories, a suitable integration and validation strategy is needed, also considering that current satellite missions do not provide TIR data with optimal characteristics to observe small thermal anomalies that may indicate changes in the volcanic activity. The presented procedure has been applied to the analysis of Solfatara Crater and is based on 2 different steps: 1) two parallel processing chains to produce ground temperature data both from satellite and ground cameras; 2) data integration and comparison. The ground cameras images generally acquire scenes of portion of the crater slopes characterized by significant thermal anomalies due to fumarole fields. In order to compare the satellite and ground cameras scenes, it has been necessary to take into account the observation geometries. All thermal images of the TIRNet have been georeferenced to the UTM WGS84 system, a regular grid of 30x30 meters has been created to select polygonal areas corresponding only to the cells containing the georeferenced TIR images acquired by different TIRnet stations. The surface temperature images retrieved by ASTER and LANDSAT data, have been georeferenced and resampled in cells of 30x30 with a careful control in maintaining the original cell values. The results show a good correspondence between trends of surface ground temperatures and satellite temperatures. This allow to calibrate the surface temperatures of the satellite imagery and to extend the area of analysis of thermal anomalies in the Campi Flegrei caldera. The effectiveness of this methodology allow to integrate the temperature data acquired by TIRNet with the satellite temperature data acquiredbefore the installation of TIRNet ground network.

Description: Published

Description: Vienna

Description: 5V. Processi eruttivi e post-eruttivi

Description: 6SR VULCANI – Servizi e ricerca per la società

Description: 5IT. Osservazioni satellitari