UAV and optical satellite data comparison to monitor surface temperature using thermal images: 2019 campaign on Italian geothermal district in Tuscany

The sites of high-temperature geothermal energy resources are commonly marked by thermal manifestation area where fumaroles, steaming grounds, hydrothermally altered grounds, hot springs, volcanic gas vents, craters, and mud pools occur. Surface thermal signatures may be used to define the evolution of development of shallow structures present on both volcanic districts and geothermal areas and possibly related to tectonic activity along active faults. These areas must be commonly subjected to geophysical monitoring where the measurements of shallow and surface temperatures may play an important role. In Tuscany several geothermal systems with a large-scale steam-dominated geothermal anomaly are presents. Remote sensing represents an effective and expedite tool to acquire infrared images when there are large extents of areas affected by thermal anomalies. However medium range (drone) to long range (satellite) thermal images are affected by errors and underestimates due both to the distance and to atmospheric absorption so they require to be calibrated with short range field measurements in order to accurately correct for these effects. In this context, systematic global cataloging of thermal anomalies as measured from high spatial resolution spaceborne sensors and acquired with thermal camera installed on drones are still in their infancy.The maps obtained by satellite data acquiring thermal imagery at suitable spatial resolution and drone measurements have been orthorectified and geocoded in order to be superimposed on digital terrain models or on the orthophotogrammetric mosaic obtained after processing photos acquired by drone.The accurate temperature measurements in land targets recorded with a variety of instruments during regular field campaigns can offer a valid methodology for the calibration and validation of satellite data.Here we show the results obtained in the last field campaign held on June 2019 during which the acquisition by Landsat8 satellite and thermal data of FlyBit have been analysed. By removing the atmosphere contribute, from Landsat8 data we have produced a surface temperature map that will be compared with the ground field measurements and surface temperature map measured by VUE PRO-R on FlyBit