Combining Ground- and ASTER-Based Thermal Measurements to Constrain Fumarole Field Heat Budgets: The Case of Vulcano Fossa 2000-2019

Vulcano Fossa's fumarole field (Italy) has been active for more than a century and has become a well-studied benchmark for fumarolic degassing, often being considered the model hydrothermal system. Satellite thermal monitoring is increasingly being used to monitor such systems, so we here use Vulcano to test a new method for assessing heat flux at such systems. Our methodology involves converting ground-based vent temperature measurements to heat fluxes emitted by the fumaroles, with the diffuse heat flux obtained from satellite-sensor (in our case Advanced Spaceborne Thermal Emission and Reflection Radiometer) data. While diffuse heat losses were typically 9 MW, vent heat losses were 1 MW. The average total flux of 10 MW over the 19-year period of study places Vulcano in the top 20 most active hydrothermal systems globally. This work highlights the value of high spatial resolution infrared satellite data in building thermal inventories for persistently active hydrothermal systems.